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The Cambridge Manuals of Science and 



C. F. CLAY, Manager 


136 Gower Street, W.C. 1 

28 Essex Street, Strand, W.C. 2 











D.SC. (LOND.) 

Director of the Rothamsted 

Ex^)evitnent Station ". ' 

Cambridge : 

at the University Press 




i i 

i II 

r 1 


First Edition IQ13 
Reprinted 1921 

Mil LiJ^fi^y ^Ric, uept;, 

ff^it^ the exception of the coat of arms at 
the footy the design on the title page is a 
reproduction of one used by the earliest known 
Cambridge printer y John Siberch, i 5 2 1 


fTlHE following pages contain the substance of 
-*- talks, lectures and other discourses delivered 
before all sorts and conditions of men and women 
and in all kinds of meeting places. Sometimes 
the listeners were labourers and allotment holders 
gathered by the schoolmaster at the close of the 
day in the biggest room of the village inn, or in the 
adult school on Sunday morning ; sometimes they 
were the more polite but not more interested culti- 
vators of suburban gardens ; others were farmers 
assembled in the market town on market day ; others 
again were professed and serious students of agri- 
cultural science. But all had this in common: that 
they were really keenly interested in the soil they 
were cultivating, and wanted to know something 
more about it. It is for such readers that this little 
book is intended. 

E. J. R. 


July 1913. 




I. The natural history op the soil ... 1 

II. How plant food is made in the soil . . 12 

III. What is soil fertility and how may it be 


IV. Soil fertility and systems of husbandry . 43 

V. The raising of the fertility limit ... 64 
Vi. The chequered career op the clays . . 86 

VII. The rise op the sands 101 

VIII. The moor— what shall it become? . . .119 
IX. Conclusion 124 

Bibliography 126 

Index .127 



1. Crops gi'own on partially sterilised soils 

2« and 2&. Experiments with Rock Phosphate, 
Illinois (Dr Cyril Hopkins) .... 

3. The Wilderness, Rothamsted (Dr H. B. 


4. Reclaimed Feniand (Mr E. R. Dixon) . 

5. Taking levels for di*aining in Puritan times . 

6. Chalking in Hertfordshire (Dr H. B. Hutchinson) 

7. Ridged land on the clay (Mr H. Cranfield) . 

8. Coxheath, near Maidstone .... 

9. Pot Culture house at Rothamsted , , . 

to face 

p. 26 



















To those who have nevel^ thought about the matter 
the study of the soil may st?em very tnviiil;vit has 
neither the glory of the celestial nor the glamour of 
the unfamiliar ; it is associated with such unintel- 
lectual and mundane concerns as food production, 
and has no place in our ordinary conception of a 
refined and liberal education. 

But the soil has not always been looked upon as 
commonplace. In the mythology of Greece it held 
a very dignified position, the Goddess Gaea being the 
mother of mankind and the bounteous provider of 
food. Right through into much later times tliis idea 
of the kindly Mother Earth can be traced, and even 
to-day the reflective gardener takes more than a 
utilitarian interest in his soil. And the light of 
Science more than justifies this interest, for it has 
shown that the soil is far more wonderful than any 
human mind had ever pictured it. 

In trying to trace out the history of a lump of 
soil we must go back to those remote times when the 

R. 1 


earth was first cool enough to allow a solid crust to 
form. When the water began to fall some of it 
soaked into the chinks and crannies of this crust, and 
by its expansion and contraction with change of 
temperature caused fragments to split off from the 
main rock. Other agencies were also effecting the 
same end, and in course of time a great quantity of 
this dismtograted vc>ck matter was formed. The 
particles did not remain where they were, but were 
carried l>y wind or water into the valleys and streams 
and many found their way to the bottom ot the sea. 
Here they mingled with the residues of plants and 
animals, and the whole mass became consolidated. 
Later on, when earth movements changed the course 
of the waters and the old sea became dry land, this 
consolidated material appeared as new rock and went 
again through the processes of disintegration and 
erosion. For a long period the surface of England 
north of the Thames, and of Canada and the northern 
part of the United States, was covered with ice which 
pounded up and carried away many of the particles, 
depositing them again when it melted. When the 
particles were lying on the dry land they were subject 
to the constant washing of the rain, the oxidising 
effect of the atmosphere, and the shattering effect 
of changing temperature, processes collectively known 
as weathering. Ever since the particles first split off 
from the original rock they have been exposed to 


these continuous disintegi'ating processes. But the 
action of these processes is exceedingly slow, or the 
particles would have disappeared entirely, or have 
become reduced to an impalpable dust. The fact 
that they survived proves them to be very resistant 
and indicates that they are not likely to undergo any 
appreciable change during the short period of time 
that interests the agriculturalist. Over longer periods 
of time, however, the different particles show different 
degrees of resistance, the most resistant being the 
grains of quartz and the least resistant the more 
complex combinations of silica and oxides of iron, 
aluminium, potassium and other metals. The latter 
have therefore suffered more than the quartz and 
have been reduced to much finer dimensions. Thus 
if a soil is separated out by mechanical analysis into 
portions, the particles of which fall within certain 
definite limits of size, it will be found that the 
coarsest particles of all — the stones and gravel — 
represent complex rock material, the coarse particles 
of the fine earth (the so-called coarse sand, fine sand 
and silt) are practically pure silica, while the finest 
particles (the clay and to a less extent the fine silt) 
contain not only silica, but oxides of iron, aluminium 
and of other metals as well. Further, the top 8 inches 
of soil that has been exposed to weathering processes 
for very long periods of time contains practically as 
much coarse material (silica) as the subsoil which has 



been shielded from these actions, but it contains 
markedly less of the finest material. 

These particles constitute the chief portion of the 
soil and may be regarded as the framework round 
which the soil is built. They show, however, certain 
differences which are of fundamental importance to 
the subject. The sands and fine silt, being formed of 
the silica, are chemically inert and practically un- 
alterable under natural conditions except that they 
may very slowly be reduced in size by weathering 
processes. The finer material, on the other hand, is 
chemically active and may not only undergo chemical 
changes, but may enter into reaction with various 
substances ; it is not a single definite compound like 
the silica, however, and cannot be represented by any 
chemical formula. It possesses other properties that 
mark it off very sharply from the coarse material. 
It absorbs a considerable amount of water, swelling 
up very much during the process ; conversely when 
it dries it shrinks a good deal. In its wet state it is 
very sticky, when dry it is very hard. It undergoes 
a remarkable change after treatment with traces of 
acids or of salts, notably calcium carbonate, and 
becomes less sticky and more easily crumbled. All 
these properties are readily observed in a clay field 
where much of this fine material is present : the 
persistent wetness of the soil, its stickiness, the large 
gaping cracks that form during its contraction on 


drying and the hard clots that result, its marked 
alteration after treatment with lime, are aU mani- 
festations of the special properties of the fine material. 
These properties are characteristic of the jelly-like 
condition, technically known as the colloidal state, 
into which many substances can be brought. 

These properties are not shown by the coarse 
material ; a sandy soil (in which the coarse particles 
predominate and the fine particles do not form more 
than 5 — 10 7o of the whole) has no great power of 
absorbing water and therefore readily dries, it is not 
sticky, does not shrink on drying or form hard clods, 
and undergoes no obvious physical change after 
treatment with lime. 

It must not be supposed that any hard and fast 
line can be drawn between the coarse sand material 
and the fine clay. One shades ofi* imperceptibly into 
the other, and so gradual is the transition that the 
special name silt is used to designate the intervening 
materiaL The lines separating sand from silt on the 
one hand and silt from clay on the other are purely 
conventional and are agreed upon by soil chemists 
in each country, but unfortunately no two countries 
accept quite the same definitions. In Great Britain 
clay is defined as any material the particles of which 
are less than '002 mm. in diameter (y^Vcio i°-) ^^^ 
silt as any material the particles of which are above 
this but below '04 mm. in diameter (q-^-^ in.) : in the 


United States, however, the limits are '005 mm. 
(s^Vt) in.) and '05 mm. (^^^ in.) respectively. 

A second group of soil constituents includes those 
derived from the organisms deposited along with the 
mineral particles while they lay under water. Of 
these the most important is calcium carbonate, the 
substance of which chalk and limestone are composed, 
and into which lime rapidly changes when added to 
the soil. As we shall see later on it plays an extremely 
important part in the soil, and profoundly influences 
the fertility and the vegetation relationships. It 
difiers from the substances already described in that 
it dissolves somewhat in the soil water, and notable 
quantities are washed out, amounting at Rothamsted 
to about 800 lbs. per acre per annum. 

Calcium phosphate also belongs to this group, 
although some is derived fi'om rock. It commonly 
occurs only to a small extent, but it is an indis- 
pensable food for plants and therefore essential to 

These two gi'oups of inorganic substances — the 
silica and complex silicates derived from the rocks, 
and the calcium carbonate and phosphate derived 
in part from organisms that once have lived — do not 
form the complete soil. A third constituent is present, 
the so-called organic matter, derived from previous 
generations of plants. It is a familiar observation 
that no ordinary soil remains long without a covering 


of some sort of vegetation. As this dies its residues 
mingle with the mineral particles, being carried in by 
earthworms and various insects. The effect of this 
addition is very great. In the first place it profoundly 
influences the amount of plant food in the soil. The 
first vegetation that sprang up must obviously have 
got its food — its calcium and potassium salts, phos- 
phates, etc. — from the mineral particles, but new 
sources of food appear for the plants that come after. 
The first crop slowly decayed under influences we 
shall deal with later on, and in decaying it set free 
those substances that its roots had taken as food and 
returned them again to the soil. Hence subsequent 
plants have food from two sources : the potassium 
salts, etc. dissolved by the soil water from the soil 
particles ; and in addition a supply of the same 
substances drawn by previous generations from the 
soil during their lifetime, but afterwards set free on 
the decay of the dead tissues. The plant food, in 
fact, keeps circulating between the soil and the plant, 
and the organic matter constitutes the medium by 
which the circulation is completed. 

The second effect of the organic matter is even 
more important. During its lifetime the plant has 
been making a good deal of the substance of its 
leaves and stems from the gases of the air and the 
rain water, and the materials thus formed contain 
stored up energy derived from the sunlight. When 


they mingle with the soil and begin to decay the 
energy is liberated in the form of heat, and by the 
time they are completely decayed they have given 
out just as much heat as if they had been burned in 
a bonfire. The original heap of mineral matter 
contained no easily available store of energy ; the 
mixture of mineral matter and plant residues on the 
other hand does. The consequence of this addition 
is very profound : life is now possible in the soil, and 
there springs up a vast population of living creatures 
all drawing on this accumulated store of energy, 
flourishing so long as it holds out, and dying off when 
it is exhausted. 

In our climate, and in humid climates generally, 
the decay of the plant residues is not complete, at 
any rate during the course of a few seasons, and some 
of the products accumulate as dark brown or black 
substances conveniently kno^vn by one name, humus. 
These substances have certain physical properties 
which they impart to the soil ; they are sticky, 
they absorb and retain water, they swell when wet 
and shrink when dry. In other words they are 
colloids. Thus the third effect of organic matter on 
the soil is to increase the amount of colloidal material, 
but some of this is of entirely different character 
from that already present. By far the most significant 
of these effects, however, is the bringing in of stores 
of energy because this constitutes the vital distinction 


between a heap of mineral matter and a soil. There 
is no soil without life, and no life is possible without 
stored up energy. We are only beginning to know 
what this soil life is, but already some hundreds of 
different kinds of creature have been found. Some 
few are large enough to be seen. Of these the most 
important are the earthworms, which burrow in the 
soil and effect a fine natural cultivation, letting in air 
and drawing in leaves, stems, and other vegetable 
debris from the surface to mingle with the mass of 
soil below. Most of the soil organisms are micro- 
scopic in size ; some lead an active life, others are 
in the inert resting stage and are called spores or 
cysts. The very incomplete census taken so far 
shows that the numbers of micro-organisms living 
in a single salt-spoon full of soil must be reckoned 
in millions. 

Some of these organisms — certain bacteria — play 
a controlling part in soil fertility because they bring 
about the decay of the plant residues and consequent 
liberation of plant food. Out of the old dead plants, 
in fact, they make food for new ones. Thus the new 
generation of plants is dependent on them, just as 
they in turn are dependent on the past generations 
of plants. As more and more knowledge is gained 
the circle of soil life widens out and other varieties 
of organisms are seen to come in, interacting one on 
the other, not all making plant food, but all dependent 


in the last instance on the energy stored up in the 
organic matter, in other words, on sunshine that was 
caught years ago by plants long since dead. 

Tliere is reason to suppose that the four gi'eat 
constituents of the soil — the inert fragments of sand, 
the reactive clay, the calcium carbonate and the 
organic matter — are not merely lying alongside of one 
another in the soil. The evidence indicates that the 
colloidal constituents form a jelly-like coating over 
the inert particles, and this jelly contains much of 
the food of plants and of bacteria ; it may be likened 
to the nutrient jelly of the bacteriologist. 

The soil mass is not solid throughout but is full 
of pores like a sponge. In a compact arable soil not 
more than 60 — 70 Vo of the volume is soil material, 
the remaining 30 or 40 % being empty space ; in 
a pasture soil the proportion of empty space is even 
greater. This pore space is at times completely filled 
with water, but more usually air is also present : at 
Rothamsted often to the extent of 10 % of the volume, 
leaving 25 Yo filled with water. The water is not 
pure but contains in solution carbonic acid, nitrates, 
carbonates and other salts of calcium, magnesium, 
etc. ; it is held in the soil partly by surface attractions 
and partly by the colloids. 

We may thus think of the soil as a porous mass 
made up of a hard framework plastered over with 
a jelly containing chemically active substances, plant 


foods, and unstable organic compounds rich in stores 
of easily liberated energy, while the pores contain air 
and a considerable amount of water. 

Into the pores of this mass we have no means of 
penetrating : no microscope has been devised that 
enables us to look into it and see what is going on. 
We have indirect but incontrovertible evidence, how- 
ever, that it is full of life and that the soil is inhabited 
by myriads of organisms of very varied kind, some of 
which, like eel-worms, are easily visible with a small 
microscope, while others, like bacteria, require a high 
power to reveal their presence. They bring about 
decay, and thus clear away the residues of previous 
plants leaving the soil clear for a new race. They do 
even more : they make the old plant material into 
new plant food. There are signs of conflicting and 
competing groups of organisms, but all at any rate 
have this in common : that they are dependent abso- 
lutely and entirely on the organic matter of the soil. 

In its main outlines this conception of the soil 
is probably correct, and every month adds to our 
knowledge of the details. But the picture is still 
far from complete and it does not enable us to 
explain all the facts about the soil that have been 
gleaned by good farmers and gardeners. Each im- 
portant discovery that is made opens out a wider 
field for exploration, and we may be certain that we 
never shall know all about the soil. 


We shall find the study of the soil very unsatisfying 
and uninspiring if we become too much absorbed in 
its utilitarian aspects and forget to stop and reflect 
on the infinite wonder of its honeycombed structure 
and its dark recesses, inhabited by a teeming popu- 
lation so near to us and yet so hopelessly beyond our 
ken that we can only form the dimmest picture of 
what the inhabitants are like and how they live. 



By far the greater part of the food of the plant 
comes from the atmosphere : oxygen, carbon dioxide 
and water between them furnish most of the material 
out of which the plant is built. But it was discovered 
long ago that something is taken from the soil, and 
that this part, although small, is absolutely indis- 
pensable to the growth of the plant. The food thus 
furnished by the soil is really composed of a number 
of substances, the most important of which are nitrates, 
phosphates and other salts of potassium, calcium, 
magnesium, sodium, etc. It is convenient to divide 
these into two groups, the nitrogenous group, such 


as the nitrates, and the mineral group, inchiding 
the phosphates, etc. of potassium and other metals. 
There is good ground for the distinction. The nitrates 
are derived almost exclusively from organic matter, 
but the mineral food, on the other hand, comes 
partly from the rock material of the soil. Further, 
the nitrates are easily soluble in water, and, there- 
fore, readily washed away ; they are, besides, liable 
to other sources of loss, while the mineral food only 
suffers slight losses. Lastly — and this aspect cannot 
be overlooked in a technical subject like ours — 
nitrates and other nitrogenous foods are by far the 
most expensive when any purchasing has to be done. 

In trying to find out how plant food is made in 
the soil, investigators have confined themselves almost 
exclusively to the nitrogenous portion. This re- 
striction was forced on the earlier workers by the 
circumstance that our soils stand much in need of 
nitrogenous manure: very much of the Rothamsted 
work has been and still is devoted to the study of 
the nitrogen problem, and a large part of our present 
knowledge is built up on the foundations laid by 
Lawes, Gilbert and Warington. We also must be 
content to accept the restriction, and pass over any 
changes which the mineral food may undergo, for 
the very good reason that we know so little about 

It was early discovered that the plant residues 


or farm-yard manure (which is essentially the same 
thing) added to the soil are not the actual food of 
plants, but only the raw materials out of which food 
is made. The true food is the nitrate to which the 
organic matter gives rise, and our first business is with 

O^ing to the losses which the nitrate sufiers there 
is rarely any great stock of it in the soil, frequently 
not enough for the current season's growth. For- 
tunately the process of nitrate production, commonly 
called nitrification, goes on fairly readily so that fresh 
supplies are forthcoming whenever the conditions are 
suitable. The process has turned out to be very 
wonderful. It was formerly supposed to be entirely 
chemical, but a remarkable piece of work by Schloes- 
ing and Miintz in 1877 showed that it was brought 
about by bacteria. In studying the purification of 
sewage by land filters they caused a stream of sewage 
to trickle slowly down a column of sand and lime- 
stone, the experiment being continued for some weeks. 
For the first 20 days the ammonia in the sewage 
remained unaltered, then it began to change into 
nitrate, and finally the issuing liquid contained no 
ammonia but only nitrate. Why, asked the authors, 
was there this delay of 20 days before nitrifica- 
tion began ? If the process were a purely chemical 
oxidation it should begin at once. If, however, it 
were bacterial, they could readily explain the delay, 


because the organisms would have to grow. To test 
this hypothesis they added a little chloroform vapour 
and found that nitrification was stopped entirely : it 
could, however, be started again by adding a little 
turbid extract of fresh soil after the chloroform was 
removed. They concluded, therefore, that nitrifica- 
tion was the work of "organised ferments." More 
rigid proof was afforded by Waring-ton and later on 
by Winogradsky. 

More recent experiments render it highly impro- 
bable that any chemical or physical process going on 
in the soil gives rise to nitrates, and we may take it 
that their production is entirely bacterial. Warington 
showed that the process takes place in two stages ; 
the ammonia is first converted into nitrites by one 
organism, and the nitrite is then changed to nitrates 
by another organism. Nobody has yet succeeded in 
finding any third stage between ammonia and nitrites 
although one might be expected on chemical grounds. 
There is practically no waste of ammonia during the 
process, and the conversion is almost if not entirely 
complete, but its mechanism is not at all understood 
and it cannot be reproduced artificially. 

The organisms which alone can bring it about are 
utterly unlike any others and completely baffled the 
earlier investigators. Bacteriologists usually grow 
their organisms on gelatine or some similar medium. 
But this plan invariably failed to bring out the 


nitrifying bacteria, and it was not till Winogradsky in 
1891 hit on the brilliant idea of using a jelly of silica, 
that they were grown and studied. Both organisms 
are extremely small — they are, in fact, the smallest 
known in the soil. Unlike the others they do not 
require organic matter as food, they make their own 
supply from carbonates or, like plants, from carbon 
dioxide. But unlike plants they do not want sun- 
light for this purpose, indeed sunlight kills them. 
Where, then, do they get their energy from ? Wino- 
gradsky adduced very strong evidence, which has 
never been disproved, that the energy comes from 
oxidation of ammonia : he found a definite relation- 
ship between the amount of ammonia oxidised and 
the amount of carbon assimilated. It appears that 
ammonia is the only compound they can utilise. 
Many other substances have been tried, but without 
results, and we can take it as proved, as well as any 
negative proposition can be proved, that ammonia is 
the only substance from which nitrates are made, 
and that all the nitrate we find in the soil has pre- 
viously been ammonia. This conclusion is very im- 
portant and leads us to look for ammonia in the soil. 
But in no arable soil yet examined has more than 
a trace been discovered at any time of the year. We 
must, therefore, conclude that the rate at which 
ammonia is oxidised to nitrite is greater than the 
rate at which it is formed. But nitrites are never 


found in normal soils. It therefore follows that the 
rate at which nitrites are oxidised is greater than 
the rate at which they are formed. 

We have, then, three reactions going on : 

Nitrogenous plant residues change to ammonia, 

Ammonia changes to nitrite. 

Nitrite changes to nitrate. 
Of these the last is the quickest, the second is slower 
and the first is slowest. The first change, therefore, 
limits the rate at which nitrates are produced : if we 
could speed up this change we should hasten the 

Further, the quickest change (the third) is most 
susceptible to external influences. Tlie organisms 
are very sensitive, they are more easily kiUed than 
the rest and they stop working more readily. Am- 
monia producers, on the other hand, are very re- 
sistant and will tolerate somewhat rough treatment. 
All three compounds, ammonia, nitrites and nitrates 
can be used as plant food, but in normal conditions 
the plant does not get the chance of using anything 
but nitrates, the other two being only transitory 

Four important facts have thus been established 
with regard to nitrification : 

(1) Ammonia is changed to nitrite and this is 
then changed into nitrate in the soil, the conversion 
being almost completa 

R. 2 


(2) Nitrates are formigd from ammonia alone, 
and not from any other substance so far as is known. 

(3) Nitrate production is the quickest of all 
the chain of processes. 

(4) The quickest acting organisms seem to be 
the most sensitive. 

We now turn to the formation of ammonia. This 
has not proved so attractive a subject for investiga- 
tion and we do not yet know much about it. Unlike 
nitrification it is not a specific property of any one 
organism, but is effected by many different kinds : it 
is not even confined to bacteria, but goes on in a 
vacuum or in presence of antiseptics. But it will not 
go on after the soil has been heated to 150°, whence 
we may conclude that one of those accelerating agents 
technically known as enzymes is also at work. It is 
difficult to say precisely how much of the decom- 
position is due to enzymes free in the soil and how 
much to micro-organisms, but it seems certain that 
the latter are by far the most potent agents. No one 
has yet gone further back in the chain to discover 
the compound antecedent to ammonia. The initial 
compound is the nitrogenous part of the plant re- 
sidues or of the substances added as manures, and 
is generally of a protein nature : enzymes, earth- 
worms, fungi and bacteria may all take part in its 
decomposition ; we may suppose that its conversion 


into ammonia will go on in substantially the same 
way in the soil as it would elsewhere : but there is no 
definite evidence in proof. 

The nitrogen compounds of the soil, however, are 
not entirely changed into nitrates: a second action 
takes place that is not in the least degree understood. 
When protein and other nitrogenous plant compounds 
are decomposed by micro-organisms in presence of 
air there frequently appears to be a large amount of 
gaseous nitrogen given off, especially when much 
organic matter is present. This change has been 
very little studied and indeed is commonly confused 
with another that appears to be wholly distinct — 
the so-called denitrification, a reduction of nitrates 
brought about by certain bacteria in presence of 
organic matter, but in ahse^ice of air. Whatever 
its nature it leads to gi-eat losses in rich or heavily 
manured soils, and is responsible for much of the 
exhaustion of virgin soils that is now going on at an 
appalling rate. One of the most pressing problems 
before the agricultural chemist is to study these two 
sets of reactions, and in particular to find out 
whether this wasteful process cannot be suppressed, 
so that a larger part of the nitrogen compounds 
shall change into the useful nitrates. In modern 
farming nitrogenous manures are by far the most 
expensive, and profits are cut so low that all sources 
of loss are to be avoided as far as possible. Both 



these actions, the formation of nitrates as well as the 
loss of nitrogen, tend to use up the nitrogen com- 
pounds of the soil, because the nitrates not taken 
by the plant are speedily washed away and lost in 
the rivers and the sea. As the original stock was 
probably never high, it is clear that there must be 
some reverse process by which the soil gains nitrogen, 
or the supply would long since have given out This 
has long been realised by men of science, and a 
careful and systematic search begun 30 years ago was 
ultimately rewarded by the discovery of two ways in 
which such a gain takes place. 

The old-established cultivator of the land has a 
great stock of information about the ways of plants ; 
some of it is disconnected and fragmentary, but it 
has to be sorted over and examined experimentally 
by the man of science. One of the old bits of know- 
ledge handed down from time immemorial, and 
already traditional when Virgil wrote his Georgics, 
was that beans, vetches, and lupins improve the land 
for the next crop. Sow your golden corn, says Virgil, 
on land where grew the bean, the slender vetch 
or the fragile stalks of the bitter lupin \ When 
Lawes and Gilbert began their experiments in 1843 
one of the early problems was to discover the reason 
for this improvement, and they were able to trace it 
to the fact that a soil was richer in nitrogen after the 

1 Georgics, Book i, lines 73 et seq. 


growth of clover than before. Somehow or other 
the amount of nitrogenous food in the soil had in- 
creased. But no one could give any satisfactory 
explanation icliy the nitrogen should increase, and it 
was not until 1886 that the solution was found. The 
story is so interesting that it must be told again, 
although it has often been told before. 

Hellriegel and Wilfarth, two distinguished in- 
vestigators at the Experiment Station at Dahme, in 
Prussia, were studying the eflfect of nitrates on plant 
growth and found that the amount of growth of 
cereals like barley, oats, etc., increased as the nitrate 
supply increased and was, in fact, directly propor- 
tional to the amount of nitrate. In the case of lupins 
and allied plants, however, no sort of proportionaHty 
could be traced, the plants sometimes did as well 
or better without nitrate as with it, but sometimes 
failed altogether. Further, chemical analysis showed 
that the quantity of nitrogen present in the cereal 
crops was just about the same as that supplied, 
while the quantity present in those peas which made 
any growth was much greater. It followed, there- 
fore, that these peas had got some of their nitrogen 
from the air. But why had not all the peas done so ? 
Hellriegel and Wilfarth argued that the success of 
the process must depend on something that only 
came into the experiment by chance. At that time 
men had bacteria very much in their minds because 


of certain wonderful discoveries that had recently 
been made. Hellriegel and Wilfarth, therefore, very 
naturally asked if bacteria could be the active agents 
here, particularly as they knew that the little swell- 
ings on the roots of the pea — the so-called nodules — 
contained bacteria, and also that some bacteria could 
take in gaseous nitrogen and use it To test the 
matter peas were sown in sterilised sand (i.e. sand 
baked so as to kill all living organisms), containing 
mineral food, but no nitrogenous food; these made 
little or no growth and developed no nodules in the 
roots. Other peas were also sown in similar sand, 
but they received a water extract of ordinary arable 
soil ; these made excellent growth and had a marked 
development of root nodules. If, however, the ex- 
tract was first boiled it had no effect in increasing 

These experiments afforded satisfactory evidence 
that the pea could form an association with certain 
bacteria which should be self-supporting so far as 
nitrogen was concerned in that it could draw on the 
immense stores of free nitrogen in the air. The 
proof was made more rigorous by other and later 
workers, and the proposition is now one of the most 
definitely established in modern science. 

Thus peas, vetches, lupins, and, we can add, beans, 
clover, lucerne, sainfoin, in short all the tribe of the 
leguminosae, take in stores of nitrogen from the 


atmosphere through their association with the bac- 
teria of the root nodules. When their roots, leaves 
or stems perish and mingle with the soil these newly- 
furnished nitrogen compounds are added to the 
general stock already there. 

A few years later another set of bacteria was 
found able to take in and use the free nitrogen of 
the air, differing from the preceding in that they 
work on their own account and do not form associa- 
tions with plants. The earliest to be discovered was 
Clostridium, but interest has centred largely round a 
later find, Azotobacter, because it works in presence 
of air and not, as happens with certain other organ- 
isms, in its absence. 

The more one studies these nitrogen-fixing or- 
ganisms the more remarkable do they appear. The 
absorption of gaseous oxygen by living organisms and 
the changes it brings about can be paralleled more 
or less closely by artificial processes in the laboratory. 
But the absorption of gaseous nitrogen by these 
particular organisms cannot be imitated in the 
laboratory and is without parallel in our experience. 
A source of energy is needed, and a considerable 
number of substances are known to serve, including 
sugar, starch, cellulose, or residues of plants. As the 
organisms are very widely distributed they may be 
expected to operate wherever supplies of easily de- 
composable organic matter are present in the soil, 


e.g. wherever vegetation is allowed to die back. It 
has been found by actual measurement at Rothamsted 
that nitrogen does accumulate in soil left to run wild 
and to cover itself with the varied assortment of 
plants cropping up in these conditions. How much 
of this is due to Azotobacter is not certain, because 
leguminous plants occur among the herbage and fix 
an unknown quantity of nitrogen. 

The organisms that we have been considering 
represent the constructive agencies in the nitrogen 
cycle in the soil, bringing in new supplies from the 
air and so making good the losses already discussed. 
It is necessary to remember — this point will con- 
stantly recur in future chapters — that these con- 
structive processes only manifest themselves in soils 
covered with permanent vegetation such as grass- 
land, woodland, etc. One exception only is known, 
viz. where a leguminous crop is growing, when the 
amount of nitrogen fixed may be considerable. With 
this exception one general rule holds : losses of 
nitrogen preponderate on soil that is cultivated, and 
gains of nitrogen preponderate on soils covered with 
permanent vegetation. In either case the action 
does not go on indefinitely: the losses become less 
and less as the soil becomes poorer, till finally they 
are so small that it is difficult to detect them, and 
the gains also become less and less as the soil be- 
comes richer, till finally they also cease or are 




balanced by losses. Thus limits are finally reached, 
and no soil becomes absolutely destitute of nitrogen 
or very rich in it; few, if any, of our British soils 
(leaving out sand dunes and peat bogs, which are not 
true soils) contain less than 0'05 per cent, or more 
than 1*0 per cent, of nitrogen. 

We may summarise the changes of the nitrogen 
compounds of the soil in diagram form thus: 


The conversion of the complex nitrogen compounds 
into nitrates is the process whereby plant food is 
made, and the fixation of gaseous nitrogen is the 
means whereby the stock of nitrogen compounds is 
maintained. Both these are obviously indispensable 
to plant growth and to the fertility of the soil. The 
other change, the evolution of gaseous nitrogen from 
complex nitrogenous compounds, appears on our 
present knowledge to be sheer waste and to serve 


no useful purpose whatsoever. AVhether or not 
further knowledge will show that it is really an 
essential part of the scheme we cannot say ; our en- 
deavour now is to reduce it as much as possible. 

More recent investigations made at Rothamsted 
and elsewhere have brought out the striking fact that 
conditions which are injurious to active life in the 
soil often bring about increases in the numbers 
of bacteria and in productiveness, while conditions 
favourable to active life often lead to decreases in 
bacterial numbers and in productiveness. 

This apparent paradox was solved by showing that 
two groups of organisms occur in the soil : the useful 
makers of plant food, and another set detrimental to 
them but, fortunately, more easily killed and slower 
in multiplying. When adverse conditions appear the 
detrimental forms suffer more than the useful forms : 
thus long severe frost, hot dry summer, heat, treat- 
ment with mild poisons that can subsequently be 
removed, all put them out of action temporarily, if 
not permanently, and so lead to greater bacterial 
activity and greater productiveness. The detrimental 
forms are provisionally identified with the protozoa 
in the soil, of which numbers have now been found. 







by toluol 

by heat 

^i >i :•. 

rartially sterilised 
by toluol 


Partially sterilisei 
by carbon 

Fig. 1. Crops grown on untreated and on partially sterilised soil 




The relation between the soil and the plant is 
not entirely simple, and in consequence no rigid 
definition of soil fertility can be given. Any par- 
ticular soil would probably prove very fertile for one 
at least of all the thousands of plants in existence, 
but if it were useless for ordinary agricultural and 
horticultural purposes it would generally be called 
barren. A fertile soil may be described as one in 
which the conditions are favourable for the growth of 
plants useful to man. 

Six requirements are necessary for the plant : 
water, air, temperature, food, root room, and absence 
of harmful factors. We must now briefly discuss 
these in their relation to the soil. 

Water supply. The soil receives water from the 
rain and from the subsoil, but it also loses water 
by evaporation and drainage. The actual amount 
present in the soil at any time therefore depends 
on several factors as it obviously represents the 
balance of gains over losses. The amount of rain- 
fall is important, but its distribution is even more 


so, in determining the amount reaching the soil 
(heavy rains being liable to run off the surface while 
lighter rains soak in), and the temperature and 
wind are great factors in determining how much 
stays there. February is one of the driest months 
so far as actual rainfall goes, but no one who lives in 
the country need be reminded how persistently wet 
the gi'ound generally is then. August, on the other 
hand, is one of the wettest months, but the soil is 
usually dry. Equally important factors are the nature 
of the surface soil, which determines how much of 
the rain percolates ; the position of the soil in respect 
of the surrounding land — whether high or low lying — 
and the nature of the subsoil, which regulate the flow 
of the underground water. 

A defective water supply may therefore be either 
the fault of the soil or its misfortune. Too much 
clay or peaty organic matter may render the soil 
impervious to rain and so cause it to lie waterlogged, 
while too much coarse sand or chalk may keep it so 
open that water rapidly drains away or evaporates ; 
in all these cases the soil is to blame. On the other 
hand, the very best soils may remain stagnant marshes 
if they occupy low-lying ground on which water 
drains from the hills without finding an outlet; or 
they may suffer badly from drought if they are 
spread out thinly on beds of gravel or of rock. The 
stagnant marsh may be drained and the soil soon 


reveals its true nature ; the rock, if thin enough, may 
be broken or removed; but the thinly spread soil 
on a gravel bed is beyond our present powers of 

When the cultivator has any reason to doubt the 
eflBciency of the water supply to his plants he must 
first ascertain whether the fault is in the soil or its 
surroundings. The bad effects of too much clay may 
be modified by liming, chalking, or drainage; exces- 
sive sand may be counteracted by additions of clay 
or silt or by ploughing in organic manures and green 
crops. In all cases the water supply is improved by 
extending the range over which the roots may grow, 
for the larger the volume of soil on which the plant 
draws the less will be the amount of water required 
from each portion. And so if any obstacle exists to 
the development of the roots it must be removed; 
the soil must be dug or ploughed more deeply and, 
in a garden, manure must be added to the lower spit ; 
any pan or thin rock layer must be broken up and 
removed ; and stagnant soil water must be prevented 
from rising too high by tapping the springs or by 
laying deep drains \ A good deal can be done by 
skilful cultivation to check evaporation and thus 
reduce the loss of water. A fine layer of soil on the 
surface effectually shields the rest of the soil from 
the sun's heat and keeps the moisture safe from loss. 

1 See p. 78. 


The constant use of the hoe in the garden reduces 
considerably the need for watering, and many a good 
gardener will declare that "the hoe is the best water- 
ing can." In dry regions the disk-cultivators are 
brought out as soon as possible after a shower so 
as to break up any crust that may have formed on 
the arable land and restore the protective coating of 
fine soil. 

Air supply. The harm that results from a water- 
logged soil is not due to the excess of water but to 
the exclusion of air. The plant roots and the food- 
making bacteria alike need air, and air must there- 
fore be allowed access to all parts of the soil. Once 
the excess of water goes the air comes in: such 
devices as liming a clay soil, lajdng drains, and break- 
ing a pan, therefore have the effect of improving not 
only the water supply but the air supply as well. 

Temperature. The heat relationships of a soil are 
also intimately bound up with the water content. Its 
mean temperature is of course directly dependent on 
its location, and does not differ gi^eatly from that of 
the atmosphere. The top half inch of soil is hotter 
than the air in direct sunshine and colder by night : 
a little below the surface the fluctuation is no greater 
than in the air, while six inches below it is much less. 
Heat only travels slowly through dry soil and does 
not affect the subsoil till some time after it has 
reached the surface. But it travels more quickly 


through moist soil ; there is less lag in transmission 
and hence less accumulation of heat in the top layers. 
Dry soils are therefore hotter at the surface in sunny 
weather, but moist soils are the more uniform in 
temperature. April showers do much to warm the 
subsoil by setting up heat communication with the 
surface and enabling the warmth of the sunshine to 
travel down ; on the other hand, winter rains cool the 
subsoil by letting out the heat stored up there. 
Another important factor is the difference in specific 
heats: water requires five times as much heat to 
raise its temperature through 1° as does dry soil, so 
that a given quantity of sunshine is less able to raise 
the temperature of a wet than of a dry soil. 

Besides these factors concerned in the warming 
of the soil there is another that has the effect of 
cooling it. Heat is required for the evaporation of 
water, and in consequence the soil is cooled when any 
of its moisture dries off. 

Several devices may be adopted in warming the 
soil. The heat received may be concentrated on 
certain parts of the soil by laying it up in ridges 
running E. and W. and therefore facing S. The 
amount retained (for some is always reflected back 
into space and lost) is increased by dressing with 
a layer of black material, soot being the most con- 
venient. Tlie effectiveness of the heat received is 
increased by draining away any excess of water. 


Finally the losses may be reduced by checking evapo- 
ration, and this can be done by sheltering from the 
wind with windbreaks or hedges and by maintaining 
the fine tilth at the surface. Horticulturists some- 
times adopt all these, agriculturalists sometimes only 
one or two. 

Food supply. The supply of plant food in the 
soil depends in the first instance on its mineral 
composition. The great mass of inert material that 
constitutes the framework of the soil and subsoil 
affords but little food. The food constituents are to 
be sought among the more soluble and reactive 
substances, and, in some way that is not sufficiently 
understood, their availability is increased when calcium 
carbonate is present. A second factor, the accumu- 
lation of plant residues, began to come into play 
soon after the soil was formed and has in some 
cases assumed so much importance that it now con- 
trols the situation. And, as plant residues are not 
themselves plant food, but have to be converted by 
micro-organisms into simpler substances, we can add 
as a third factor the activity of the food-making 

It is a simple matter to increase the supply of 
plant food by adding fertilisers to the soil. The 
amount of nitrogen may be increased by adding 
nitrate of soda, sulphate of ammonia, organic sub- 
stances such as farmyard manure, guanos, certain 


manufacturers' waste products, etc. or by gi'owing 
leguminous crops. Since the loss of nitrogen is con- 
siderable recourse must often be had to one of 
these methods, and grave doubts have at times been 
expressed as to how long the world's supply of 
nitrogen compounds would last. Of late years, how- 
ever, it has been found practicable to make nitrogen 
compounds from the inexhaustible stock of nitrogen 
in the air; the world's supply of nitrogen manures 
can therefore be increased whenever necessary, and 
the dreaded nitrogen famine has been relegated to 
the time when the energy supply shall give out. 

Phosphates are supplied in the form of bones, 
guanos, basic slag and rock phosphate. Most soils 
contain insufficient to satisfy the large crops pro- 
duced by the modern farmer; frequent additions 
are therefore necessary, especially under conditions 
of high farming. The losses are not as serious as 
those of nitrogen. There is practically no washing 
out; the agricultural chemist can still detect the 
phosphates added to the lands round the cities of 
ancient Egypt. Nevertheless there is a steady and 
continuous loss in the crops which has to be made 
good. There is no way of adding a single ounce to 
the world's stock of phosphorus compounds, and this 
is being drawn upon even now to the extent of some 
millions of tons each year, while the demand increases 
steadily as time goes on. If some day the supply 

R. 3 


gives out, and at present it seems inevitable that it 
must, mankind will be faced with perhaps the most 
serious of all catastrophes, a phosphorus famine. 

But there is no immediate cause for alarm, as on 
the lowest computation the visible supply will last 
for many years. Further, the phosphates lost from 
the farm are not destroyed but find their way to the 
sewage, and thence to the sea. We must therefore 
look to the ocean for the means of replacing the land 
deposits of phosphates, and already a fair amount is 
drawn from this source in guano, fish meal, etc. 

The supplies of potassium compounds already 
existing in the soil are in general sufiicient for 
ordinary purposes, but additional supplies become 
necessary as the character of the farming improves 
and larger crops are grown. Some special soils, 
such as peats, chalks, and thin sands, need potassium 
fertilisers in order to yield even small crops, and 
much labour has been lost through ignorance of this 
fact. The deposits of potassium salts are extensive 
and in Germany's keeping; no needless waste is 
therefore to be apprehended. In the last instance 
the ocean can be made to give up some of its 
enormous stock. 

The nature of the plant residues and the ease 
with which they are decomposed by bacteria depend 
on climatic factors — the temperature, water supply, 
etc. — and also on the amount of calcium carbonate 


present. These various relationships have already 
been discussed at some length: we need now only 
point out that a water supply suitable for ordinary 
plant growth seems also to be very suitable for 
bacterial activity. The rule seems to apply also to 
other soil conditions, and we may make the general 
statement that a soil suited to the growth of plants 
is also suited to the activity of bacteria and there- 
fore to the production of plant food. The similarity 
becomes even more close after the soil has been 
partially sterilised so as to destroy detrimental 

A further connection between the food supply and 
the water supply lies in the fact that the food has 
first to be dissolved in the soil water before it can 
enter the plant. Roots have no power of taking in 
solid matter ; they can only imbibe solutions ; further, 
they cannot use strong solutions, but may even be 
injured thereby as in some of the alkali lands; and 
they do not make very good growth in too weak 

Even this is not all. The amount of plant food 
per unit volume of the soil is not the only factor 
determining the amount of food the plant can get; 
the extent of the root range is equally important just 
as it was in the case of water. 

Root range. And this leads to the question of 
root room. No plant does well unless it has ample 



space for the fall development of its roots. It suffers 
from the restriction of its supply of water and of 
food, and apparently from other causes as well ; recent 
experiments seem to indicate that new factors may 
come into play when one set of roots runs up against 
others because there is not space for both. In 
Mr Pickering's experiments at Woburn growing grass 
had a very detrimental effect on the fruit trees 
planted in it, and there is also evidence that weeds 
may have a directly harmful action on sown crops. 

Absence of injurious factors. However good its 
food and water supply, a soil may remain infertile if 
injurious substances happen to be present. Little 
attention has been paid to these in England, but they 
have been much studied in the United States where, 
indeed, they have given rise to considerable contro- 
versy. It seems beyond dispute that substances 
harmful to plants do occur in wet soils poor in 
calcium carbonate. Nothing is known about these 
substances (in English soils, at any rate) but some 
years ago the fashion arose of calling them acids 
without any sufficiently rigid proof It is distinctly 
unwise to prejudice future investigations by assign- 
ing a name already used for a definite group of 
substances to another that is yet unstudied, and we 
shall therefore adopt the nomenclature of the prac- 
tical men and speak of such soils as "sour." Whatever 
the cause of "sourness" (and the name commits us 


to no hypothesis), it can be remedied by drainage, 
lime, and good cultivation. 

Cases are recorded of infertility arising from 
excess of iron or of manganese in the soil, but no 
satisfactory evidence is afforded in proof. Drainage, 
lime and good cultivation are here also found to be 

"Sickness" of soil has in the past been attributed 
to the presence of a toxin, but more recent work 
indicates that it is biological in nature and remedied 
by partial sterilisation. 

The alkali soils of dry regions owe their sterility 
to excess of soluble salts; they may be treated by 
drainage (which is a first essential), irrigation, and 
addition of gypsum where much sodium and potas- 
sium carbonates are present. Much interesting work 
remains to be done in elucidating the causes of 
infertility of certain special soils. 

Looking back over these various fertility factors 
we see that they are not a mere tangle of unrelated 
things, but are very closely connected one with the 
other. The water supply, air supply, and temperature 
are to a large extent mutually interdependent, and 
changes in any of them are reflected in the food 
supply. We can simplify matters by selecting three 
as the leading factors in normal cases: the water 
supply, food supply, and stock of calcium carbonate ; 
when these are satisfactory it will usually be found 


that the other three conditions are also favourable 
to plant growth. 

Soil Types. 

In order to increase the soil fertility it is necessary 
first to seek out the factor limiting plant growth and 
then to remove it. As the different soil types have 
certain characteristic limiting factors we can now 
advantageously turn to them for a time. 

Sandy soils consist chiefly of inert silica with only 
about 6 per cent, or even less of clay, and are con- 
stitutionally poor in those mineral compounds that 
give rise to plant food. Any stock that might 
originally have been present is constantly being 
reduced by solution in the rain water that drains 
through. They are therefore poor in plant food. 
But on the other hand, if they are fi^ee from such 
obstructions as layers of rock, hardpan, or stagnant 
water, they allow of very copious and deep develop- 
ment of plant roots. The actual volume of soil upon 
which the plant may draw for food and water is con- 
siderable, and in consequence sandy soils yield better 
crops than might at first be supposed. Generally 
also the crops ripen well and give early produce of 
good quality. Only small amounts of calcium car- 
bonate appear to be necessary to prevent sourness. 

The deficiency in food is readily made good 
by frequent small additions of manure. The water 

Ill] THE LOAMS 39 

supply tends to be erratic because of the great ease 
with which rain water soaks into the depths of the 
soils, but it can be made more regular by additions 
of organic manures or of clay. The defects of a sandy 
soil are mainly negative, i.e. they can be remedied 
by adding something, whilst its advantages are very 
real; it induces good root development, early yield 
and high quality. There is, perhaps, a wider range 
of possibilities for a sandy soil than for any other ; 
it may be a desolate heath, or it may, under proper 
management, blossom out as a fruit and vegetable 
garden, giving each year two or three crops of good 
produce. But the cost of the process may be more 
than the result is worth. 

Soils that contain more of the fine clay material 
and proportionally less sand are called loams. It is 
impossible to define loams exactly: the cultivator 
recognises them by the fact that they are definitely 
coherent and not loose like sand, yet not over-sticky ; 
and further that they allow free root development. 
But there are no sharp lines of demarcation ; many 
soils at one end of the scale would be called light 
loams by some practical men and sands by others, 
while at the other end soils called heavy loams by 
some would be regarded as clays by others. In 
between these limits there remains a great body of 
soils which most cultivators would agree to call 
loams, and these on analysis are found to contain 


6 to 15 per cent, of clay, 40 to 60 per cent of the 
silts and 20 to 50 per cent, of coarse and fine sand. 

Loams contain more plant food than sands and in 
general have a better water supply ; they therefore 
yield heavier crops. But the crops are often not as 
early as those grown on sands. 

The next group, the clays, cannot be sharply 
marked ofi* from the loams but can only be described 
generally as sticky soils, persistently wet in winter 
and spring, and drying to hard clods in dry weather. 
They contain more actual clay^ and less sand than 
the loams, but none appears to contain more than 
50 per cent, of clay, very few contain as much as 
40 per cent., and most "clays" contain only about 
25 per cent, or less. In consequence of their sticki- 
ness clays do not allow very free root development. 
The root range being thus restricted, plants do not 
draw on anything like the same volume of soil for 
food and water as in the case of loams and sands. 
Hence the clays are less fertile than these soils in 
spite of the fact that they often actually contain 
more food and water. Of course if the plant is in 

1 Unfortunately soil chemists use the word "clay" in two distinct 
senses: (1) the soil or mineral as a whole, (2) the fine material less 
than -002 mm. in diameter (-005 mm. in the United States). In past 
years another meaning was given which does not appear to have been 
very definite ; this survives in the statement handed solemnly down 
through eighty years of text books that a clay soil contains "75 to 
95 per cent, of clay." Ceramic chemists adopt a different definition. 


the ground a long time it can develop a big root 
system and then it will grow well : trees, grass and 
the longer-lived deep rooting arable crops, particu- 
larly wheat and beans, do very well. Each of these 
types of soil has its advantages: sands are easily 
workable and present great possibilities in the way 
of cropping : loams give good heavy crops of almost 
any of the ordinary farm and market garden plants : 
clays are very well suited to grass, wheat, and beans, 
three crops of considerable importance to the farmer. 
A really strict comparison is not possible because the 
types are so different, but in the main we must give 
the palm for fertility to the loams. The districts 
in our own country famous for their fertility are 
commonly loams; they are often alluvial deposits 
bordering the sea, as in the Chichester district, or 
lying in broad valleys, as in the vale of Evesham; 
they are assured of an ample water supply by 
their position, and favourably situated in regard to 

But we must never forget that every soil will bear 
gome plants well although they may not happen to be 
saleable at the time. Gervase Markham's list drawn 
up in 1620 needs but little change to-day. "Ground 
which, though it bear not any extraordinary abund- 
ance of grass, yet will load itself with strong and lusty 
weeds, as Hemlocks, Docks, Mallows, Nettles, Ketlock 
and such like, is undoubtedly a most rich and fruitful 


ground for any grain whatsoever. And also, that 
ground which beareth Reeds, Rushes, Clover, Daisies 
and suchlike, is ever fruitful in Grass and Herbage.... 
When you see the ground covered with Heath, Ling, 
Broom, Bracken, Gorse or such like, they be most 
apparent signs of infinite great barrenness.... And of 
these infertile places, you shall understand, that it is 
the clay ground, which for the most part brings forth 
the Moss, the Broom, the Gorse, and such like; the 
sand, which bringeth forth Brakes, Ling, Heath, and 
the mixt earth, which utters Whinnes, Bryars, and a 
world of such like unnatural and bastardly issues." 

It was largely owing to the circumstance that 
mankind was unwilling to pay for "Whinnes, Bryars, 
and a world of such like unnatural and bastardly 
issues" that the "mixt earth" was called infertile. 
Tastes alter — who would now accept Markham's de- 
scription of heather as "only a vile filthy black brown 
weed"? — and a plant despised by one generation may 
be prized by the next. Perhaps the most permanent 
piece of advice one can give to the cultivator of a 
piece of poor land is to find out what plants it will 
grow well, decide which will be most profitable, then 
ascertain what is preventing the soil from growing 
these better, and, finally, if possible, remove the 
hindrance, whatever it may be. The gap between 
the ideal and the actual conditions for the crop may 
be narrowed from both ends: the plant may be 


altered somewhat by the breeder, and the soil con- 
ditions may be changed in some of the ways to be 
described later on. Nothing but disappointment, 
however, is likely to follow attempts at growing 
plants or crops unsuited to the soil conditions. 



We have seen that there is a close relationship 
between the composition of the soil and the vegeta- 
tion growing on it; an even closer connection can 
be traced between the fertility and the system of 

Virgin land covered with its native vegetation 
appears to alter very little and very slowly in 
composition. Plants spring up, assimilate the soil 
nitrates, phosphates, potassium salts, etc., and make 
considerable quantities of nitrogenous and other 
organic compounds : then they die and all this 
material is added to the soil. Nitrogen-fixing bac- 
teria also add to the stores of nitrogen compounds. 
But, on the other hand there are losses: some of 
the added substances are dissipated as gas by the 
decomposition-bacteria, others are washed away in 


the drainage water. These losses are small in poor 
soils, but they become greater in rich soils, and they 
set a limit beyond which accumulation of material 
cannot go. Thus a virgin soil does not become 
indefinitely rich in nitrogenous and other organic 
compounds, but reaches an equilibrium level where 
the annual gains are offset by the annual losses so 
that no net change results. Tliis equilibrium level 
depends on the composition of the soil, its position, 
the climate, etc., and it undergoes a change if any of 
these factors alter. But for practical purposes it may 
be regarded as fairly stationary. 

When, however, the virgin land is broken up by 
the plough and brought into cultivation the native 
vegetation and the crop are alike removed, and there- 
fore the sources of gain are considerably reduced. 
The losses, on the other hand, are much intensified. 
Rain water more readily penetrates, carrying dissolved 
substances with it: biochemical decompositions also 
proceed. In consequence the soil becomes poorer. 
But the impoverishment does not go on indefinitely : 
the rate of loss diminishes as the soil becomes poorer, 
and finally it is reduced to the same level as the rate 
of gain of nitrogenous organic matter. A new and 
lower equilibrium level is now reached about which 
the composition of the soil remains fairly constant; 
this is determined by the same factors as the first, 
i.e. the composition of the soil, climate, etc. 


Thus each soil may vary in composition and 
therefore in fertility between two limits: a higher 
limit if it is kept permanently covered with vegetation 
such as grass, and a lower limit if it is kept permanently 
under the plough. These limits are set by the nature 
of the soil and the climate, but the cultivator can 
attain any level he likes between them simply by 
changing his mode of husbandry. The lower equili- 
brium level is spoken of as the inherent fertility of 
the soil because it represents the part of the fertility 
due to the soil and its surroundings, whilst the level 
actually reached in any particular case is called its 
condition or " heart," the land being in " good heart " 
or " bad heart," according as the cultivator has pushed 
the actual level up or not : this part of the fertility is 
due to the cultivator's efforts. 

The difference between the higher and lower fer- 
tility level is not wholly a question of percentages of 
nitrogen, carbon, etc. At its highest level the soil 
possesses a good physical texture owing to the floc- 
culation of the clay and the arrangement of the 
particles: it can readily be got into the fine tilth 
needed for a seed bed But when it has run down 
the texture becomes very unsatisfactory. Much 
calcium carbonate is also lost during the process: 
and when this constituent falls too low the soil 
becomes "sour" and unsuited to certain crops. 

The simplest system of husbandry is that of 


continuous wheat cultivation, practised under modern 
conditions in new countries. When the virgin land 
is first broken up its fertility level is high ; so long as 
it remains under cultivation this level can no longer 
be maintained, but rapidly runs down. During the 
degradation process considerable quantities of plant 
food become available and a succession of crops can 
be raised without any application of manure. In fact 
there is commonly more plant food than the crop 
needs and addition of manure gives no crop increase. 
Hence arises the idea that the land needs no manure, 
and the pioneer, fully occupied with the pressing needs 
of the moment, not only supplies none, but does not 
even put back into the soil any part of what he takes 
away. The grain is sold and the straw is either burnt 
or dumped into gullies. After a time the unstable 
period is over and the new equilibrium level is 
reached at which the soil will stop if the old hus- 
bandry continues. In this final state the soil is often 
not fertile enough to allow of the profitable raising 
of crops; it is now starving for want of those very 
nutrients that were so prodigally dissipated in the 
first days of its cultivation, and the cultivator starves 
with it or moves on. 

"0 man, that from thy fair and shining youth 
Age might but take the things youth needed not." 

Such is the history of many of the derelict farms in 
parts of the United States and such must inevitably 

Fig. 2 a. Crop grown ^Yithout phosphates on a worn out 
soil in Illinois 

Fig. 2 b. Showing what phosphalf s will do on worn out 
soils in Illinois 


be the history of many farms elsewhere so long as 
continuous wheat culture is adopted. It is futile to 
speak of land as inexhaustible: fertility is no more 
inexhaustible than any other form of capital. The 
pitiful thing is that so much of the loss is sheer 
waste: about one third of the plant food goes into 
the crop, the rest is lost beyond hope of recall as 
gas into the atmosphere or as saline matter in the 
drainage water and the streams. It is not the crop 
that exhausts the land but the continuous cultivation. 

Fortunately recovery is by no means impossible, 
though it may be prolonged. It is only necessary to 
leave the soil covered mth vegetation for a period of 
years when it wiU once more regain much of the 
nitrogenous organic matter it has lost. But it does 
not wholly recover. The phosphates and potassium 
salts removed in the crops, and the calcium carbonate 
leached out, are not regained ; for want of them the 
growth of recuperative vegetation may suffer. 

The problem has been investigated with charac- 
teristic energy in the United States, and a remedial 
scheme has been evolved by Dr Cyril Hopkins, 
Director Thorne and others, based on experience 
in the older countries and on careful experiments 
in the new. The central feature is that continuous 
tillage must stop, and for one third to one half of its 
time the land must lie untilled and covered with 
vegetation, i.e. in the course of six years not more 


than three or four gram crops should be taken; 
during the remaining time the land grows grass or 
leguminous crops, so that it may gain organic matter. 
It is not unremunerative during this period; on the 
contrary, these crops are distinctly valuable. Much 
the best for the purpose are clover, either alone or 
mixed with timothy, and lucerne ; these collect gase- 
ous nitrogen as well as carbon dioxide to form 
nitrogenous organic matter in the soil. It is an 
indispensable part of the method that limestone 
should previously be added to the soil, or the clover 
or lucerne may fail. When the soil has been thus far 
improved the supply of phosphates present may be 
insufficient for the crop that can be produced, and 
this limiting factor has therefore to be removed by 
the addition of rock phosphates. The crop now 
increases till it is limited by some new factor. It 
may happen that the supply of potassium salts in 
the soil constitutes this new limiting factor, in which 
case addition of potassic fertilisers becomes desirable. 
The fertility may then rise higher than it was at first 
in the virgin soil. 

The whole process, it will be observed, consists in 
the successive removal of the limiting factors. 

The exhaustion of the virgin lands constitutes the 
simplest case because everything is removed from the 
soil and nothing is put back. It could only arise under 
conditions of cheap transport facilities between the 


virgin land and the cities where the gi-ain is to be 
consumed. Thus it is essentially a modern pheno- 
menon ; it never arose in so acute a form in England 
because such facilities did not exist till a complex 
system of agriculture was already established. Wheat 
has always been grown in this country and records 
exist of very early exports. Zosimus relates {Hist 
Nova, lib. 3, ch. 5) that Julian brought wheat from 
Britain to feed the inhabitants of some of the Rhine 
cities whose stores had been destroyed and their 
harvest ruined by insurgent tribes. But we have 
no knowledge what the agricultural methods were. 
When the first definite records of English agriculture 
appear a system was already in use that kept the soil 
fertility at a sufficient level for the needs of the time. 
In medieval England the arable land occurred 
partly in the lord's demesne and partly in the com- 
mon cultivated field \ The latter was divided into 
fields, generally three in number, which were again 
divided into strips so distributed among the tenants 
that each should have his share of good and bad land. 
The pasture consisted of the common grazing land, 
certain outlying lands, and the cultivated common 
field after the harvest was off"; in addition there were 
certain fields and water meadows not held in common. 
The live stock thus had a relatively wide area of 
ground over which to gather their food; and their 

1 Often called "infield" in the North. 


manure, mingled with any bracken, straw, rushes, 
etc., gathered for litter, went to fertilise the arable 
land. The distribution was not very uniform, as the 
lord often had special claims, but all the arable land 
did receive some dung. 

The manure having been put on, a crop of wheat 
or rye or both was taken. After harvest the in- 
dividual cultivators no longer had any special rights 
in their strips and the whole field became common ; 
the fences were removed and the cattle allowed to 
enter and graze the weeds and grasses. The ground 
was somewhat enriched by folding on it sheep that 
had grazed during part of the day on the common. 
This period lasted from Lammas Day^ (August Ist) 
till Candlemas (Feb. 2nd). The land was next sown 
with barley, oats, or other spring or " Lent " corn, and 
after harvest (Lammastide) again grazed until the 
following Candlemas. It was then ploughed up and 
left fallow throughout the summer ; finally it was 
dunged and sown with wheat. Occasionally, however, 
barley was taken first and wheat after : 

"First rie, and then barlie, the champion saies, 
or wheat before barlie be champion waies; 
But drink before bread come with Middlesex men, 
then lay on more compas, and fallow agen^." 

1 Lammas Day (Aug. Ist) may seem early to a modern farmer for 
the individual rights to cease and the whole field to become common, 
but it must be remembered that the Julian Calendar was then in 
force so that the date is really later than it looks. 

2 Tusser, Five Hundred Pointes of good Husbandrie, Octobers 


Whatever the order, the rotation consisted of two 
corn crops and a fallow ; each year one of the fields 
was fallow, the second wheat or rye, and the third 
Lent corn. 

The dung made by the animals contained elements 
of fertility derived from the pasture land. The addi- 
tion of this dung to the arable land thus involved a 
transfer of fertility from the wide areas of the pasture 
land to the smaller areas of arable land. The process 
maintained the fertility of the arable land, but it must 
in time have impoverished the pasture ; but the im- 
poverishment of the pasture went on only very slowly 
for two very interesting reasons. In England the 
supply of nitrogen compounds in the soil is most 
frequently the factor limiting the wheat and other 
grain crops ; so long as the nitrogen supply is kept 
up a certain level of crop production can be main- 
tained. In pasture land a considerable amount of 
nitrogen fixation is continually going on through 
bacterial activity. Hence the element that played 
the most serious part in fertility under the conditions 
of low yields then obtaining was being brought in as 
quickly as necessary from the atmosphere. 

The next substance to give out and cause the 
collapse of the system would have been calcium 

husbandrie, 1573: drink corne = barley ; bread come = wheat ; compas 
= farmyard manure (compost); champion = the unenclosed common 
field or its farmer. 



carbonate. There was a real danger of this, but it 
was met by chalking and marling which from time 
immemorial had been part of the agricultural practice 
of these islands (see p. 80). In consequence soil 
exhaustion could only set in through exhaustion of 
the phosphates and potassium salts, and this was a 
very slow process which, moreover, was still further 
delayed by the practice of fertilising with wood 
ashes, which supplied potassium salts derived from 
the forest, and less frequently with salt (sodium salts 
economising the consumption of potassium salts by 
the plant). Thus the only weak point in the system 
was the exhaustion of phosphate from the soil, but as 
the yield of wheat was probably often under 10 bushels 
per acre, which would only take out some 5 lbs. of 
phosphoric acid (P2O5), and as the total population 
was only small and sparsely scattered, the system was 
for ail practical purposes permanent. But the yield 
was very poor. 

The next step up involved some very drastic 
changes. Gradually the common arable fields and 
pastures began to be enclosed and each man's holding 
came into one piece. The process was slow and is 
hardly complete even yet; the old strip farming of 
common fields may still be seen in the Isle of Axholme, 
Lincolnshire, while survivals of it may be detected in 
many villages. For example, several arable common 


fields can be traced around Harpenden; Manland, 
Westfield and Pickford Commons are divided by 
balks into strips as in medieval times. During the 
fifteenth and sixteenth centuries the enclosure was 
accompanied by the wholesale conversion of arable 
into grassland induced by the high price of wool, and 
both processes were much resented by the peasantry, 
who pulled down the new hedges in many places, and 
in Norfolk broke out into open rebellion under Kett 
in 1549. Shrewd writers of the period saw, however, 
that only on enclosed land could a higher level of 
productiveness be attained, and history has shown 
that only on such land were improved methods 

Under the new conditions each man could grow 
what he liked (unless the landlord forbade him), and 
he was no longer tied down to follow ancient custom. 
There was a greater incentive to industry, more 
manure could be obtained and grea^ter care could be 
taken with the cultivations and to keep down weeds. 
In consequence larger crops were now obtained ; the 
yield of wheat has been estimated for certain districts 
at about 20 bushels, barley at 30, oats and pulse at 
40 bushels per acre at this period. There can be little 
doubt that at this pace exhaustion would have been 
hastened, and the more so as chalking, marling and 
other permanent improvements were falling into dis- 
use through the insecurity of the tenant's position. 


A further improvement was soon to take place in 
soil fertility. A great advantage of the enclosure 
over the common fields was that crops could now 
be grown in autumn and winter ; obviously this 
course was impossible when the village cattle strayed 
at will over the land from Lammastide to Candlemas. 
Consequently about the middle of the seventeenth 
century turnips, clovers, and cultivated grasses came 
in from Holland — the source of many of our great 
improvements — and slowly took their place in our 
agricultural system. Before these new crops could 
be cultivated a great improvement was needed in 
methods of tillage. The old implements were very 
crude: heavy wooden ploughs turned up the earth 
in great clods that could not be broken up by the 
inefficient harrows ; so that after the seed had been 
broadcasted the clods had to be broken in pieces 
by large wooden hammers. "It is a greate labour 
and payne to the oxen, to goo to harowe; for they 
were better to goo to the plowe two dayes, thanne to 
harowe one daye. It is an old saying, 'The oxe is 
neuer wo, tyll he to the harowe goo.'... And if the 
barleye gounde wyll not break with Harrows, but 
be clotty, it wolde be braken with malles, and not 
streyght downe : for than they brake the corne in-to 
the earthe," wrote Fitzherbert in 1543. Two hundred 
years later Tull declaims against farmers who, " when 
they have thrown in their seed, go over it twenty 


times with the harrows, until the horses have trodden 
it almost as hard as a highway." The young plants 
thus had considerable difficulty in getting through, 
and later on in the season they were terribly ham- 
pered by the excessive gi'owth of weeds which could 
never be got rid of by the old methods. 

These defects were only slowly remedied, but the 
man who probably did more than anyone else in this 
direction was Jethro Tull. Travelling in the South of 
France and in Italy in the early years of the eighteenth 
century, he observed how carefully the vineyards were 
cultivated. On his return home he adopted similar 
methods on his farm at Shalbourne, on the borders of 
Berkshire and Wiltshire, adapting and inventing the 
necessary implements. Some farmers, indeed, had 
already begun to get a fine tilth : he tells us of 
"Great quantities of very light land (in Gloucester- 
shire) which when kept in the sat erit^ husbandry were 
let for half a crown an acre, but being now brought 
into the pulverising method, are let for ten shillings 
an acre. But there is a misfortune in many parishes, 
that the custom does not permit any one to pulverise 
his light lands by tillage, until an enclosure be made 
of them." 

Tull insisted on three points: (1) that the soil 
must be thoroughly pulverised before the seed is 
sown, (2) cultivation must continue after the seed is 

^ Tail's name for the old style. 


sown and as long as is practicable, (3) the seed must 
therefore be sown in straight lines and not scattered 
broadcast. The seed drill and horse hoe that he made 
to carry these principles into practice have been the 
forerunners of a long line of useful implements, and 
they alone made possible the cultivation of turnips, 
clovers and other of the new crops that began to 
come in. 

These new crops completely changed the agricul- 
ture of the country. They fell best into the rotation 
worked out by Lord Townshend in the middle of the 
eighteenth century : clover in place of the old fallow, 
then wheat, then turnips, and lastly barley. Three 
great advantages followed. The clovers and other 
leguminous plants, sainfoin, lucerne, etc., led to a 
great increase in the stock of soil nitrogen. The 
substitution of a growing crop for the fallow con- 
siderably reduced the wastage of plant food through 
leaching. The clover hay and turnijjs provided food 
for the live stock throughout the winter, so that it 
was no longer necessary to slaughter them in late 
autumn and salt them down to be eaten ^; the hus- 
bandman was able to keep them alive and in good 
condition all the year round. The animals consumed 

^ **At Hallowtide, slaughter time entereth in, 

and then doth the husbandman's feasting begin." 

Tusser, 1673. 


a great deal of food, but this did not necessitate a 
great net loss to the soil. For the carbon, hydrogen 
and oxygen (the elements most largely retained in 
the body tissues) came from the inexhaustible supplies 
in the atmosphere, while of the other constituents, 
retained to a less extent and largely passed off into 
the manure, the nitrogen was mainly drawn from the 
atmosphere through the agency of the clover, and 
only the phosphorus, potassium, calcium, etc., came 
exclusively from the soil. This manure when put 
on to the land actually enriched it in nitrogenous 
organic matter, and went far to replace the mineral 
substances withdrawn by the previous year's crops. 
So far as nitrogen was concerned, the system was 
permanent: crop production went on at a higher 
level than was ever before possible, and this new 
level was determined in principle by the amount of 
nitrogen fixed by the quadrennial clover crop, and in 
practice by the amount that was returned to the soil 
in the manure. 

But there still remained the loss of phosphorus, 
which was intensified as the cities grew and imported 
more and more dairy produce, meat, bread, etc., from 
the country. At the end of the eighteenth century, in 
spite of all the improvements, an ordinary yield of 
wheat was probably only about 23 bushels, little 
more than good farmers had been accustomed to 
get for 250 years past. The improvements had been 


by no means universally adopted, and in many dis- 
tricts medieval agriculture was still the rule. It is 
impossible to determine how far the low yield was 
due to this circumstance. But in many cases the 
small supply of phosphates in the soil was now the 
limiting factor, preventing the crop from rising. 

Then gradually bones came into use as manure and 
produced such remarkable results that from the early 
years of the nineteenth century considerable quantities 
were imported from Europe. It would, perhaps, be 
unkind to enquire too particularly where they came 
from : Liebig roundly declared that " England is 
robbing all other countries of their fertility. Already 
in her eagerness for bones she has turned up the 
battlefields of Leipsic, and Waterloo, and of the 
Crimea: already from the catacombs of Sicily she 
has carried away the skeletons of many successive 
generations.... Like a vampire she hangs upon the 
neck of Europe, nay, of the whole world, and sucks 
the heart blood from nations without a thought of 
justice towards them, without a shadow of lasting 
advantage to herself" 

But even finely ground bones sometimes acted 
only slowly and sometimes failed to act at all. This 
was the case at Rothamsted: during the years 1836 — 
1838 Lawes had used bone dust on turnips without 
avail, although it was effective elsewhere. He there- 
fore prepared the soluble calcium phosphate, then 


known as superphosphate, by treating the bone with 
sulphuric or other acids. This proved remarkably 
effective on turnips; and he took out a patent in 
1842 and commenced the manufacture on a large 
scale. But as the source of the calcium phosphate 
was immaterial, he used mineral phosphates and 
guanos instead of bones. 

Another source of phosphatic manures was opened 
up in 1879 when Thomas and Gilchrist introduced 
their process for removing the phosphorus from iron 
during its conversion into steel. At first the agri- 
cultural value of the basic slag thus produced was not 
recognised, but it was slowly revealed by the experi- 
ments of Wrightson and Munroe in 1885, and of other 

Phosphatic guanos, brought fi'om the Pacific 
Islands, fish guano worked up fi'om refuse fish, and 
meat guano from imported meat, contribute in a 
lesser degree to the farmers' supply. 

As a result of having these large supplies of 
phosphates from various parts of the world, farmers 
now very generally add phosphates to their land, and 
thus remove the limiting factor which had in many 
cases kept down the crops. Concurrently with the 
increased use of phosphates there has been a marked 
increase in soil fertility, the yields of turnips in 
particular have gone up very much, and there have 
been very great improvements in the pastures. More 


cattle can therefore be kept and more manure can be 
made for the arable land. 

It often happens, especially on the lighter soils, 
that the crop supplied with phosphates is now limited 
by the deficiency of potassium salts. This deficiency 
has long been partially met by dressings of wood 
ashes, salt, etc., but a better method was needed. 
Fortunately large supplies of potassium salts were 
discovered at Stassfurt in Germany and were put on 
the market in 1861. Since then they have been ex- 
tensively used, although curiously enough no similar 
deposits have been found elsewhere. 

The modern farmer is no longer dependent on 
leguminous plants for his supplies of nitrogen. 
Nitrate of soda is imported from Chili, sulphate of 
ammonia is manufactured from coal at home, and a 
large number of grains and seeds are imported from 
over the seas to feed tlie cattle and thus increase the 
supply of farmyard manure. 

Modern agricultural systems are far too complex 
to reduce to any simple rigid order ; but their general 
bearing on the fertility of the soil may be briefly 
summed up: 

1. The supply of plant nutrients is kept up by 
the addition of appropriate artificial manures. It is 
impossible to determine a priori either by chemical 
analysis or otherwise exactly Avhat mixture of manures 
will be best ; nothing but direct trials suffice. But a 


number of trials are being made, and in some cases 
on a defmite systematic plan, to ascertain broadly the 
needs of the commoner crops on important types of 
soil. Chalk or lime is also applied, though, it must 
be said, not always as often as necessary. 

2. Every effort is made to keep up the supply of 
nitrogenous organic matter in the soil. It is not yet 
possible, and perhaps never will be, to maintain the 
same level as in land permanently covered with grass 
or other vegetation. But leguminous crops are grown ; 
the " seeds " (i.e. mixture of grass and clover) are left 
for two or three years, in which time a dense root 
mass forms; and in many instances a crop (such as 
mustard, tares, etc.) is sown with the deliberate in- 
tention of being ploughed into the ground. 

3. Enormous quantities of cattle food are im- 
ported from newer countries and from less highly 
developed regions. Only a small part — not more 
than five or ten per cent. — of their nitrogen, phos- 
phorus and potassium is retained by the animal : the 
rest passes into the manure and goes to fertilise the 
land. There are, however, very considerable losses 
in making manure, and as much as one half of the 
fertilising constituents may fail to reach the soil. 
Greater economy is effected by feeding the animals 
on the arable land, thus obviating the necessity for 
making farmyard manure. 

4. Crops are therefore grown suitable for animals 


to eat in the field (sheep are the most convenient for 
the purpose). These crops include swedes, rape, 
kohl-rabi, thousand-headed kale, mustard and the 
aftermath of clovers and cultivated grasses \ The 
purchased food is su]3plied in troughs and the animals 
are confined by hurdles to a particular area till the 
crop and sufficient additional food are consumed. 
Then they are moved on, till finally they have 
covered the whole field. 

5. Considerable tracts of land are laid down to 
permanent pasture. Judicious management of graz- 
ing, combined with dressings of basic slag, lime and 
potassium salts if necessary, lead to the formation of 
a dense turf of grass and clover. The land thus gains 
considerable supplies of nitrogenous organic matter 
and its fertility rises to the upper equilibrium level. 
These areas of well-managed grass land constitute, 
perhaps, the most fertile soils we have, and their 
fertility is more permanent, and maintained at lower 
cost, than that of any other soils. 

Thus the modern English farmer keeps up the 
fertility of his soil by importing phosphates from the 
United States, Tunis, Algeria, Belgium and France; 
nitrates from Chili ; potassium salts from Germany. 
He also imports grain — maize, wheat, barley, oil 
seeds, etc. — rich in valuable fertilising materials from 
the United States, Russia, Roumania, Argentina, 

1 Often called '♦ rotation grasses." 


British East Indies, Canada and other parts of the 
Empire. Thus a prodigious transfer of soil fertility 
is taking place from these countries to our own. The 
process at present is enormously wasteful. We have 
seen that terrible losses of fertility may arise under 
conditions of pioneer farming ; even the remnant 
saved in the crop suffers further loss in many a badly 
arranged British farmyard and exposed manure heap. 

Lastly, the crops raised on the British farm are 
largely sent off to the cities from whence only little 
manure ever returns, the great proportion of the 
fertilising constituents getting into the sewage and 
being destroyed at considerable expense. 

It is obvious that such wasteful methods cannot 
go on indefinitely. Investigations into the losses and 
gains are now going on at Rothamsted and elsewhere. 
With fuller knowledge there is little doubt that some 
of the waste can be reduced, while the action of the 
recuperative agencies in the soil can be accelerated. 
It is impossible to overestimate the importance of 
evolving a permanent system of maintaining soil 
fertility, but such a system must rest on a solid 
foundation of scientific fact. 




We have seen in the previous chapters that the 
fertility of a given soil may lie anywhere between 
two limits : the higher limit being attained when the 
land is allowed to remain with an undisturbed vegeta- 
tion of grass and clovers, and the lower when the 
land is perpetually under the plough, producing 
nothing but cereal crops and receiving no manure to 
counterbalance the various losses. We have further 
seen how, by a judicious system of husbandry, it is 
possible to maintain arable land somewhere near the 
higher fertility limit by arranging for recuperative 
periods in grass and clover, and systematically adding 
manurial substances to replace whatever may be lost. 

The higher limit beyond which the fertility of the 
soil as it stands cannot be pushed, is set by the nature 
of the soil, its position in respect to water supply, 
climate, etc. But it is often possible to change these, 
and when this is done the fertility is no longer tied 
down to the old limit but rises to a new one set by 
the new conditions. This process is of course funda- 
mentally different fi'om the case we have just dealt 
with, and is in practice so much more costly that the 


distinction is recognised both by custom and by law : 
the maintenance of fertility between the natural 
limits is regarded as the tenant's business, while the 
extension of the upper limit is considered to be the 
landlord's duty. 

Over the greater part of England such an exten- 
sion of the fertility limit has taken place. Often 
indeed the extension was necessary before the adop- 
tion of expensive modern methods of farming could 
be justified. The process has generally involved some 
conflict with natural conditions, and the new order of 
things stands only so long as constant care is exercised. 
In most cases the original condition is resumed if the 
intervention of man ceases for a time ; a plot of land 
at Rothamsted that has been left to itself since 1882 
is now a dense thicket and bids fair to become an 
impenetrable wood before long. But the expenditure 
necessary to maintain the new limit is much less than 
that required to reach it, so that in this sense the 
improvement is entitled to be called permanent. 

Some of the land of England has always been 
open gi'ass-covered Down land, and this was inhabited 
even in prehistoric times. Much of the land, however, 
was covered with forest which had to be cleared away 
before fields could be made but which would, as the 
Rothamsted experiment shows, soon spring up again 
if the suppressing hand of man were removed. It is 
difficult for us now to realise the magnitude of the 

R. 5 


task which medieval man set himself in clearing the 
forest with his imperfect tools and the enormous 
amount of labour that must have been required. 
Even with modern appliances — explosives and well- 
constructed jacks — the task is considerable, and the 
traveller round the shores of Lake Erie can still find 
many fields from which the timber has been removed, 
but the stumps still left, because the labour of 
removing them is so great that no adequate return 
could be obtained. 

Clearance was still going on in England even as 
late as the middle of last century and an interesting 
account of one is preserved in the Journal of the 
Royal Agricultural Society for 1863. About ten 
miles west of Woodstock lies the forest of Wychwood, 
that formerly occupied considerably more land than 
it does now. In 1853 an Act was passed permitting 
disafibrestation, and in October 1856 the work was 
begun. The account deals only with the portion 
allotted to the Crown, an area of nearly 3000 acres 
lying in the triangle between Fulbrook, Field Assarts, 
and Shorthampton. Of this nearly 2000 acres were 
"unreclaimed forest land, dense, dark, and gloomy: 
its silence seldom disturbed, except by the axe of the 
woodman, tlie gun of the gamekeeper, or the stealthy 
tread of the deer stealer." 

Ten miles of road were first made, and these, with 
their boundary walls, cost £6985. Then it was 


necessary to get rid of the deer. "The Commis- 
sioners' order had gone forth against the deer 'let 
not one remain.' Some few were caught alive in nets, 
and taken away to stock distant parks, but by far the 
greater number had to be killed, and to effect this 
purpose the keepers were fully employed ; to assist 
in the slaughter, guns and gunners came from the 
surrounding neighbourhood. . . . As a complete clearance 
was to be made, bucks, does, and fawns, in season 
and out of season, shared the same fate, and the taste 
of venison was known in cottage as well as hall." 
Next the trees were cut down. "Hundreds and 
hundreds of men and boys were engaged, some cutting 
the light wood and laying it in drift, some tying the 
firewood into faggots, some preparing the larger 
pieces for posts and fencing and others busy felling 
the timber trees, or stripping off the bark." Some of 
the smaller trees were pulled down by a windlass 
worked by two horses. The total cost of this was 
£7742, but sales of timber, bark, etc. realised £21,823, 
and as £2450 worth was left untouched the gain on 
this part of the operation was £16,531. Next came 
the laborious process of digging out the roots known 
by the old Saxon name "grubbing"; this was accom- 
plished by hand labour at a cost of £6233 for an 
area of 1903 acres. " Some of the roots were carried 
away to serve as fuel for the cottages near ; but 
great quantities were burned on the land, rough 



firewood in the district having become so abundant, 
that it was not considered worth the expense of 
cartage." The ground being now clear, seven farms 
were measured out and whitethorn quicks planted 
along the boundaries ; houses and buildings were 
put up at a cost of £14,337. Allowing for all sales, 
the net outlay apart from the ten miles of road Avas 
£10,452 and the total farm land obtained was 2843 
acres ; this was let at £5104 per annum, a gain of 
£3291 on the revenue derived from the forest. But 
the land was by no means ready for cultivation. The 
tenants, as they came into possession on 31 years leases, 
found " anything but a smooth, inviting appearance : 
wide ditches, and long, irregular high banks that 
had formed the boundaries of the different coppices ; 
deep pits and hollows, where stones had been dug 
for the use of bygone generations: small straggling 
briars that had escaped the notice of the woodgrub- 
bers ; roots of trees and underwood, left a few inches 
below the surface by oversight or intentional neglect 
on the part of dishonest workmen ; large patches of 
rough brown fern-stems, that had afforded covert to 
the fawns; all these and many other impediments 
stood in the way... it was with the greatest difficulty 
that four strong horses drawing a large iron plough 
could break up half an acre a day; and many and 
long were the blacksmith's bills for repairs. Some of 
the tenants tried digging, at a cost of £3 per 


acre; some used stocking-hoes, and grubbed the 
gi'ound 5 inches deep, carefully picking out the large 
stones that were beneath the surface ; this plan cost 
50/- per acre. On Potter's Hill farm, breast plough- 
ing and burning was adopted ; and this course 
appeared to answer better than any of the others." 
The banks were either thrown do^vn by spade labour 
to fill up the hollows, or gradually ploughed down. 
Vast quantities of wood ashes were available for 
manure and were spread as required on the fields. 
Oats and turnips were grown during the first year, 
much of the cultivation being done by hand; the 
yield of the former was well up to the average of the 
district and of the latter well above it (probably 
because this crop had received superphosphate) and 
for the five years over which the record extends the 
tenant was satisfied with the returns. The landlord 
(the Crown) was also well satisfied ^ The recorder 
further lays stress on the great moral gain to the 
district — a point strongly emphasized by all advocates 
of enclosure. "Formerly, when deer and game 
abounded on the coverts, deer-stealers and poachers, 
idlers, and thieves, were numerous around; conflicts 
between them and the keepers were frequent; im- 
prisonment and transportation caused many families 
to lose their paternal head, and where matters did 

1 I understand that over the whole fif t^' years the returns have not 
been so satisfactory. 


not reach this point, perhaps the abiding influences 
were still worse, a stolen buck could readily be 
disposed of; the amount paid for such plunder 
frequently amounted to £2 or £3, but as ill-gotten 
booty is seldom well spent, the beer-shops too often 
absorbed the greater part of the proceeds. Tliere 
was squandered in dissipation, what had been dis- 
honestly obtained, a deserted home, a neglected wife, 
and children left to their own devices, fill up the 
background of this sad picture." 

In this particular instance clearing only was 
carried out, but in many other cases further opera- 
tions have been performed. Chief among these is 
drainage, which has been resorted to in all parts of 
England owing to the circumstance that the wetness 
of many soils more than anything else set the fertility 
limits and often in fact rendered them absolutely 
sterile. The old method in this country consisted in 
throwing the land into high ridges with deep furrows 
between, such as can still be traced in almost any clay 
district. Considerable waste of land was thus entailed : 
the furrows were often so wet that they lay bare of 
crop, whilst only the higher parts of the land were 
productive. No advance seems to have been possible 
in the common arable lands, as nothing could be done 
without the consent of all the owners ; but on the 
enclosed fields better methods could be adopted. 

A special drainage problem had, from time 


immemorial, been solved successfully in various parts 
of England. Much of Romney Marsh in the South of 
Kent was reclaimed from the sea before or during 
Roman times, while the adjoining Walland and Denge 
Marshes were brought in and drained by successive 
Archbishops of Canterbury beginning about 774. 
The great monasteries in the Fens had also reclaimed 
parts of the surrounding land. In 1626 a great 
scheme was set into operation for draining the Fens 
and embanking its rivers, the work being executed 
by a celebrated Dutchman, Cornelius Vermuyden. 
As this is essentially an engineering problem we 
cannot go into the details of the methods adopted; 
nor does space allow any account of the romantic 
story of the project, its interruption by storm, by the 
exhaustion of the resources of the Adventurers, by 
the Civil War, and finally by the fenmen themselves, 
who had no taste for farming and no wish to see 
wheat and cattle take the place of fish and waterfowl. 

"Behold the great design, which they do now determine, 
Will make our bodies pine, a prey to crows and vermin ; 
For they do mean all fens to drain and waters overmaster 
All will be dry and we must die, 'cause Essex calves want 
pasture " 

went the old fenman's song. 

The scheme as it works to-day consists of two 
great parts: (1) the water from the high lands is 
intercepted and discharged into the river so that it 


shall not reach the low-lying lands, (2) the water 
inside the low-lying area is drained into ditches and 
pumped into the river. To effect the first purpose a 
catch- water drain is cut at a point just above flood 
level and arranged to discharge by gravity into the 
nearest river. The second purpose is achieved by 
making open drains inside the catch-water and bring- 
ing them to the most convenient point for discharge. 
The water collected in these is below the level of the 
river and will not naturally flow in, but has to be 
lifted there. This is done by large scoop wheels, 
which are simply under-shot water-wheels driven the 
reverse way. In olden times power was furnished by 
windmills, and now-a-days by the less picturesque 
beam engine. Oil engines and centrifugal pumps are 
often used in new work. 

The reclamation of Whittlesea Mere near Peter- 
borough (Holme Station) affords an interesting in- 
stance of this type of problem. The Mere itself 
covered 1000 acres, and around it lay another 2000 
acres of wet land or shoals. In 1844 an Act was 
obtained to improve the drainage of the Middle 
Level; a new cut 11 miles long was commenced to 
discharge the waters some six miles further down the 
Ouse than before, and so effect a lowering of the 
water table by six feet. Simultaneously connection 
was made with the Mere. In the summer of 1851 
the new cut was sufliciently advanced to carry oft' the 

Fig. 4. Reclaimed fenland, Lincolnshire 

I tf •> «> ■ 


waters, the last bank was cut through and the Mere 
began to empty itself. There was a total fall of only- 
two feet from the bottom of the lake and accordingly 
the stream was never rapid after the first twenty-four 
hours and was still flowing sluggishly even after 
three weeks. Fortunately a favourable wind pre- 
vailed and assisted materially the movement of the 
water. "Long before the last pools of water had 
disappeared from off the bed of the Mere," wrote 
Mr Wells, from whose description in the Journal of 
the Royal Agricultural Society for 1860 this account 
is taken, "large crowds of people from all the sur- 
rounding neighbourhood had assembled. Some from 
a desire to be present at the last moment of a 
venerable friend whose fortunes were now reduced to 
the lowest ebb: others perhaps with whom the love 
of stewed eels preponderated over sentiment, from 
the prospect of a ready and abundant gratification of 
their taste.... Nine out of ten came provided with 
sacks and baskets to carry off" their share of the vast 
number of fish, which, wherever the eye turned, were 
floundering in the ever-decreasing water. Some 
more ambitious speculators brought their carts, and 
gathering the fish by the ton weight, despatched 
them for sale to Birmingham and Manchester." 

A pumping engine was now installed to carry the 
water table sufficiently below the surface for crop 
production. During the summer of 1852 the great 


expanse of mud was surveyed, farm boundaries 
marked out, and arrangements made for letting some 
of the prospective farms, when on November 12th 
the bank broke and the whole Mere was flooded 
again to a depth of 2 J feet. But the bank was 
mended and the engine set to work; in little more 
than three weeks the mud surface was once more 
exposed. Then a main dyke was cut through the 
area, and a number of smaller lateral dykes; this 
work was very arduous and the mud frequently fell 
in. But it was finished at last and the pump re- 
moved the water as fast as it collected. " The effect 
of this network of drains was quickly visible. The 
bed of the Mere was soon covered with innumerable 
cracks and fissures, deep and wide, so as to make it a 
matter of no small difficulty to walk along the 
surface, while in the surrounding bog the principal 
effect was the speedy consolidation of its crust.... 

" It was no easy matter to reduce the Mere-land 
into a state to receive such seed as should be first 
sown ; the adhesive condition of the surface making 
it impossible to use horses even when shod with 
boards, if indeed the wide fissures did not render it 
dangerous to try the experiment. The whole area 
therefore had to be prepared by hand — over the 
largest part light harrows were first drawn by hand — 
the seed was then sown, and the harrows used a second 
and sometimes a third time, at a cost of about 5/- or 


6/- per acre. Other parts were dug or forked at an 
average cost of from 25/- to 30/- per acre. Of such a 
depth were the cracks, that even this process with all 
the subsequent operations attending the first crop, 
by no means got rid of these obstinate scars, which 
continued until the cultivation of three or four years 
at length obliterated them." 

Coleseed and Italian rye grass were the first crops 
taken, and after that wheat and oats could be grown 
owing to the richness of the soil and its large content 
of calcium carbonate. Excellent yields of these 
cereals, of mangolds, potatoes and carrots were 

There remained the more difficult business of 
rendering fit for cultivation the tract of peat land 
surrounding part of the old Mere. This was done by 
covering the peat to a depth of 4 to 6 inches with 
the marl dug out of the dykes; the operation cost 
£15 to £19 per acre but proved remunerative as the 
land readily let at 30s. per acre. 

Thus a vast unhealthy waste of marsh and mere 
was transformed into healthy agricultural land and 
made to produce food valued then at over £12,000 
per annum. To this day it remains a fertile tract. 
One interesting change has, however, set in. As the 
water drained away so the soil shrunk, and it has 
fallen in level to a remarkable extent. Oak posts 
driven into the underlying gault till their tops were 


flush with the mud in 1851 are now more than ten 
feet above the surface. 

Many of the magnificent alluvial meadows of the 
country have been made in the same way from rushy 
wastes. The well-known Brooks at Lewes give an 
example : originally only a bog of bullrushes, let for 
a trifling sum to chair bottom makers, they have for 
the past 80 years been fertile pastures carrying sheep 
and bullocks, yielding heavy crops of hay and contri- 
buting much to the wealth of the district 

These large schemes were early imitated by a few 
progressive agriculturists troubled with marshy or 
boggy fields. Walter Blith, a Yorkshire Puritan and 
"lover of Ingenuity," as he styled himself on the title- 
page of his English Improver (1649), had indeed 
already published methods that the farmer could 
adopt. He begins by pointing out that the causes of 
soil infertility "are usually two, 1 in Man himself, 2 in 
the Laud itself. In Man himself it was occasionally, 
who by his sin procured a curse upon the Land, even 
Barrennesse." Of the defects in the land, one of the 
worst can be removed by " Drayning, or taking away 
Superfluous and Venomous Water, which lyeth in 
the Earth, and much occasioneth Boggiuess, Miriness, 
Rushes, Flags, and other filth, and is indeed the 
chief cause of Barrenness in any land of this nature." 
He goes on to set out the essential condition that the 
drains must fall gradually but consistently from the 

Fig. 5, Taking levels for draining in Puritan times 

(From Walter Blith, The English Improver Improved or the Survey 
of Husbandry Surveyed, 1652) 


highest land to the lowest where the outfall must be, a 
condition which, even in the middle of the nineteenth 
century, was not always acted upon. "Be sure thy 
Drains be such, and so deep, as thou hast a descent 
in the end thereof to take away all thy water from 
thy Drayn to the very bottom, or else it is to no use 
at all, for suppose thou make thy Drain as high as an 
house, and canst not take thy wa,ter from it, thy work 
is lost ; for look how low soever is thy lowest level in 
thy Drain, thou mayst drain thy water so low, and 
not one haire's breadth lower will it drain thy gi^ound 
than thou hast a fall or descent to take it cleanly 
from thy Drain ; therefore be especially carefuU here- 
in, and then if thou canst get a low descent from 
thence, carry thy Drain upon thy Levell untill thou 
art assuredly got under that moysture, miriness, or 
water, that either offends thy Bog, or covers thy 
Land; and goe one Spades graft deeper... to the 
bottom where the spewing spring lyeth thou must 

The drains must be laid out straight with as few 
"Angles, Crookes, and Turnings" as possible, and 
proper levels taken ; the various tools and appliances 
needed are described and pictured in detail. Good 
green faggots of willow, alder, elm or thorn or else 
"great Pibble stones or Flint stones" are to be put 
into the trenches, on top of this some turf facing 
downvrards, and then the whole filled in. 


But it was nearly two hundred years before the 
plan was adopted on any wide scale by farmers or 
landowners. In 1823 James Smith, of Deanston, 
Perthshire, drained a marshy piece of ground in this 
manner and converted it into a garden. The interest 
of farmers in the experiment was aroused and main- 
tained: in 1831 he set out the results of this and 
other trials in his Remarks on Thorough drainage 
and Deep ploughing. He recommended stone drains 
(like Blith's) 2 to 2^ ft. deep to be made in the furrows, 
or, on flat land, 10 to 15 ft. apart in heavy soils but at 
wider intervals in lighter soils. Josiah Parkes, the 
drainer of Chat Moss, took a different view which he 
defended in his papers in the Journal of the Royal 
Agricultural Society (1846, etc.) and in his book 
Philosophy and Art of Land Drainage (1848). He 
maintains that drains should be deep — not less than 
4 to 6 feet but they could be placed at wider intervals. 
The stones were soon displaced by John Reade's pipes 
of 1843, which in 1845 were turned out by the 
thousand in Thomas Scragg's machine. Throughout 
the 'forties and succeeding years drainage became a 
very popular improvement ; public loans were raised, 
companies were started, and individuals expended 
their resources in developing great schemes. But 
the question of the depth of the drains was not 
settled; considerable controversy went on between 
the advocates of Smith's and of Parke's methods; 


and it was not till thousands of acres had been 
wrongly drained and thousands of pounds wasted, 
that the germ of truth underljing both sides was 
discovered. For both sides were partially right; 
deep drains are needed to carry off subterranean 
water and shallow drains to remove surface water. 
Modern practice tends to revert to Smith's method ; 
the drains are now commonly put 2J to 3| feet deep 
and 15 to 30 feet apart. In one other point a change 
has been made ; the pipes are now often 3 inches in 
diameter instead of one or two inches as formerly. 

Where the drainage was carried out effectively 
a most striking improvement resulted. The ground 
lost its wet sticky character. It could be ploughed 
earlier in the year, so that the seed could be sown 
early, and the crops safely left growing later. As the 
excess of water was removed air took its place ; better 
root growth now became possible and considerable 
increases in crop were obtained. Great improvement 
also set in on the grass land ; the reeds and rushes 
disappeared and the grasses and clovers flourished. 
But the change is not entirely permanent ; the drains 
gradually become blocked up with silt, with a deposit 
formed of oxide of iron together with organic matter, 
and with roots of trees or plants ; and considerable 
areas of land in the country now require redraining. 

We have seen that the most generally fertile 


soils are the loams, which consist of sand, silt and 
clay together with calcium carbonate. Soils lacking 
any of these constituents are usually less productive, 
but the fertility limits are raised directly the lacking 
constituent is supplied. 

Thus a sandy waste may be made productive after 
addition of clay: and a dense clay soil may be 
ameliorated by adding calcium carbonate, and to a 
less extent by adding sand. These processes are 
simple enough in principle but require considerable 
human labour in practice, so that now-a-days they are 
relatively costly. They are among the earliest im- 
provements in our agriculture, being known and 
practised by the Britons according to Pliny ^. His 
account of the process afibrds an interesting glimpse 
of the agriculture of those far-off days. " The peoples 
of Britain and Gaul have discovered another method 
for nourishing the land. There is something they 
call marl (marga). It contains a more condensed 
richness, a sort of fatness of the land.... There were 
formerly two kinds only, but several have lately been 
put to use by clever men: the white, the red, the 
columbina, argillaceous, tui^-like, and sandy are all 
used now. Marl is two-fold in nature : hard or fatty ; 
these can be distinguished by the touch. In like 
manner it has a two-fold use ; some kinds are used 
for crops (fruges) only, others for herbage (pabulum) 

1 Book 17, 6. 


only. The tufa-like variety is good for crops. The 
white kind found in streams is extremely rich ; it is 
hard to the touch ; if too much is put on it burns the 
soil. The red kind is called acaumimarga, it contains 
hard lumps of petrified sandy fragments. This is 
broken on the ^eld itself and in the first years the 
stubble is only cut with difiiculty on account of the 
stones. It is put on very sparsely, only half as much 
being used as of the other kinds. They think it is 
mixed with salt. Either of these kinds put on the 
land will last for 50 years. 

"Of the fatty marls the chief are the white 
varieties. There are several of these: the sharpest 
is the one above mentioned. Another is the silvery 
chalk. It is sought for deep in the ground, wells 
being frequently sunk 100 ft. deep with the mouth 
narrow and the shaft widening out as in mines. This 
is the kind most used in Britain. It lasts for 80 years 
and there is no instance of anyone who has put it on 
twice in his life time. A third white marl is called 
glisomarga, it is a fullers chalk mixed with rich soil 
more productive for herbage than for crops, so that 
after the harvest and before the next sowing there 
springs up a rank growth to be cut. When it is 
applied to crops it produces no other vegetation. It 
lasts for 30 years ; if put on too thickly it strangles 
the soil. The columbina marl is called eglecopala by 
the Gauls, it is equally fertile. It is turned up in 

B. 6 


lumps like stones and shatters into little fragments 
under sun and frost. They use the sandy kind if no 
other is available, and in any case on marshy soil. 
The Ubii are the only people I know of who make 
land fertile by digging up the soil to a depth of about 
3 feet and then throwing on top a foot's thickness. 
That kind does not last more than 10 years." 

To this day the "silvery chalk" is dug out in 
Hertfordshire just as Pliny describes : a well is sunk 
and widened out to a chamber as the chalk is reached: 
the chalk is hauled up and spread on the gi'ound. 
The well is partly filled in and leaves one of those 
dells so characteristic of the fields of the county. 

The method that Pliny ascribes to the Ubii has 
been very much used. Light barren sands are often 
underlain by heavier loam or clay which when brought 
to the surface give rise to a fertile soil. Instances 
will be given in Chap. VII. 

It is not always necessary that the material should 
be carried by human labour; the forces of Nature 
can sometimes be utilised. Perhaps the best illustra- 
tion is furnished by warping, a process introduced 
during the early eighteenth century into North Lin- 
colnshire and South East Yorkshire and practised 
under the name of Colmatage in Tuscany, Romagna, 
and the neighbourhood of Naples. 

The Ouse, the Trent and other rivers connected 
with the Humber are tidal, and as the flood travels 



up stream it is seen to be loaded with mud scoured 
off from the banks and shores lower down. Much of 
the land lies below high-water level and consists of 
barren sand or peat. It is therefore divided up into 
areas of suitable size (200 acres or more is not un- 
common) which are surrounded by banks and then 
connected with the river by means of wide channels 
fitted with sluice gates. When the flood is high the 
sluice gates are opened and the water runs over the 
area and is left to stand for 3 or 4 hours. There it 
deposits its mud: it is then allowed to run off and 
the mud is left to dry as much as possible before the 
next tide is due. The process is repeated daily at 
both tides so long as the tides are high enough ; the 
inlets are periodically shifted and the incoming flood 
is skilfully managed to ensure that the deposit is 
spread fairly uniformly. In course of three years the 
deposit is some 2 or 3 feet in depth. The new land is 
now left undisturbed to dry for a time and to get 
some of its salt washed out; it is so^vn with white 
clover and left for some time to consolidate ; then it 
can be drained and levelled and used for ordinary 
agricultural crops. Potatoes, wheat, roots, clover and 
rye-grass are commonly grown ; they are often arranged 
in a three-year rotation, first potatoes (well manured 
with superphosphate and nitrate of soda, but no 
potash, as this is unnecessary), then wheat and finally 
roots, the clover mixture or oats. The land is very 



fertile, yielding 10 to 14 tons of potatoes, 7 to 9 quarters 
of wheat and still larger crops of oats ; it lets readily 
at £2 per acre per annum and is considered to be 
worth £40 to £50 per acre, whilst the average cost of 
warping is only some £20. The improvement is 
permanent, although sometimes the shrinkage of the 
land becomes so great after a few years that re- 
warping is desirable to bring it up to its old level. 

The process is obviously only possible where the 
land lies below the level of ordinary high tides. One 
large district, Thorne Moors, is in the main rather 
too high and an interesting modification is here 
adopted. The Moors are mainly peat, and peat is an 
article of distinct commercial value; it is therefore 
dug out, dried, and broken in a disintegrator; the 
coarser part is made up into bales and sold in the 
cities as peat moss litter, while the finer material 
is sent abroad to be soaked with molasses and 
then used as cattle food. Some also is distilled 
for the sake of its products. An area of about 200 
acres is thus excavated to a sufficient depth — some 
5 ft. or more — and the warping is then begun. 

The defects of a clay soil cannot so easily be 
remedied as they arise from an excess of clay and 
fine silt rather than a deficiency of anything. Under 
special conditions reclamation has been effected by 
digging in great quantities of coarser material: a 


considerable tract of land is being treated with city 
refuse at Murieston, Midcalder, by the Edinburgh 
Distress Committee and a marked improvement in 
productiveness has resulted. 

Thus the land that we cultivate to-day is far 
removed from virgin land; it has been cleared, en- 
closed, levelled, often embanked, drained, chalked 
and marled by successive generations of cultivators. 
No small part of the difficulty of dealing with eco- 
nomic land problems arises from the great amount of 
capital that has been expended in the past in effecting 
the necessary improvements. In many cases the rent 
now received for agi'icultural land affords no adequate 
return for the outlay incurred even during the past 
sixty years. On the other hand it is arguable that 
improvements in land are a condition of national 
existence and therefore lie outside the scope of 
investments made for profit. We cannot now go 
into a discussion of these social and economic prob- 
lems. The important conclusion is that our land 
owes much of its fertility to the labours of those who 
have gone before us. The improvements they effected 
are not wholly permanent but have to be maintained 
and renewed by each generation ; any neglect of this 
duty may result in marked deterioration of the land 
and may necessitate considerable expenditure of time 
and money to bring back the fertility to the level at 
which it had formerly stood. 




A CLAY soil needs no description. Everyone is 
familiar with the grey, green or dirty red coloured 
soil, sticky and slippery after rain, on which in 
winter time pools of water lie for days or weeks 
together. In the summer it dries to hard intract- 
able clods, shrinking so much during the process 
that great gaping cracks appear, making the fields 
unsightly and in extreme cases even somewhat 

But although its general properties are very 
characteristic and easily recognisable no one has 
succeeded in drawing up any rigid definition of what 
is and what is not a clay soil. No sharp line of 
demarcation exists in IN^ature, and the clays shade 
off by imperceptible gradations into the wholly 
different class of soils known as the loams. 

Agriculturally the clays are diflicult to plough 
because of their stickiness, and for the same reason 
they make rather dangerous habitats for seedlings. 
It is no uncommon experience to have to sow a 
secoi^.d time because the first lot of seeds have be- 
come asphyxiated Even Avhen the young plants 


have struggled through, their troubles are not at an 
end, for with the first spell of hot dry weather the 
soil dries to a solid crust that is little, if any, better 
for them than the wet sticky mass produced by heavy 

The great difference in agricultural value between 
clays and loams is sharply revealed by a study of the 
face of the country. 

Loams, as we have already seen, are very generally 
fertile and are practically all under cultivation. In 
a loamy district almost every available piece of land 
has at one time or another been taken up, and little, 
if any, waste land is left. Space is economised as 
much as possible ; there are few, if any, village greens 
or commons, and even the very lanes and roads 
are narrow and often worn deep by the heavy traffic 
of bygone days when road-making was still a 
lost art. 

The hedges are straightened out and well kept, 
ditches are filled in unless actually wanted, and the 
whole country has a well-cared-for appearance. But 
in a heavy clay district there was less temptation to 
take in the land so completely. Indeed, some of the 
worst of the land probably never was taken in at all, 
but remains covered with forest apparently pretty 
much in its primeval state. Biean Forest near Can- 
terbury, King's Wood running along the North Dotvtis, 
many acres of wood in the Weald of Kent, all occupy 


land that has never been coveted by agriculturists, 
and so has always remained untouched. Even 
where the land has been taken up the process was 
very incomplete: village greens and commons have 
been left, the roads are wide, much wider, in fact, 
than need be now-a-days, so that only a part is made 
up and the rest is left as untidy picturesque wastes 
of bramble and briar, inhabited occasionally by a 
few roving gipsies or tramps, but of no practical 
value to anyone else. The fields are often small 
and the straggling hedges and ditches occupy a dis- 
proportionally large area of the land. The hedges 
are badly kept and the bushes have been allowed to 
develope into trees, so that looking over a clay region 
such as the Weald of Kent one gets the impression 
of a heavily wooded country. The farming is reduced 
to its simplest, grass only is grown because that 
involves least trouble and expense, and the land 
is worked with the lowest possible expenditure of 
money and labour. 

Such heavy unremunerative soils can be found in 
places on the clays of the Coal Measures, the Oxford 
Clay, the Weald and elsewhere. They merge in- 
sensibly into lighter and more tractable soils, which 
in turn shade ofi* into the fertile loams. But no 
limits can be set anyw^here. At one end of the series 
we have valuable fertile loams, at the other end clay 
wastes; and somewhere in between come a number 


of soils which pay to cultivate when prices are high, 
but are unprofitable when prices fall; they then 
bring disaster on the holders and soon go out of 
cultivation. These soils occupy in the aggregate a 
pretty considerable area of the country, and their 
history is extraordinarily interesting, because it so 
accurately reflects the chequered life of the agri- 
cultural community. 

Many of these borderland soils first came into 
cultivation during the Napoleonic wars when prices 
of wheat rose to the highest level ever reached. In 
the years of depression between 1813 and 1836 they 
went out of cultivation and were commonly allowed 
to cover themselves with weeds and grasses, and afford 
miserable grazing for unfortunate live stock. After 
they were drained in the early 'forties they became 
once more productive, and during the prosperous years 
of the 'fifties and 'sixties they were in great demand. 
Then when the bad times came, culminating in the 
disastrous season of 1879, the clay lands again fell 
out of cultivation. With a return of prosperity they >^' 
were once again cultivated, and now-a-days we find. ; 
them converted into good pasture for dairy cattle or 
fatting stock and into arable land growing wheat, 
mangolds, cabbage and, where possible, potatoes. It 
needs but little foresight to see that in the next 
wave of depression some of them may again go out 
of cultivation. 


All this time, however, the loams have remained 
in cultivation in spite of all vicissitudes of prices and 
of seasons. 

The story that we have briefly sketched out must 
now be studied with a little more detail. 

The ancient method of dealing with clays was to 
lay them up in high backed ridges so that the rain 
could run off into the furrows. There it often lay for 
long periods. On these high backed lands cross- 
ploughing was impossible ; cultivation was not deep ; 
the surface being v/orked only to the depth of two or 
three inches and the subsoil was never touched. Only 
the ridge carried a crop of any size : the furrows were 
too wet in winter and too hard in summer to allow of 
plant growth. 

Chalking and marling were commonly adopted in 
good times or whenever circumstances were pro- 
pitious to permanent improvements, but they were 
neglected in bad times in spite of the advice of all 
agricultural writers. " Howsoeuer this Weald," writes 
Gervase Markham in 1625^ of the clay plain forming 
the Weald of Kent, " be of itselfe vnfruitful and of 
a barren nature, yet so it hath pleased the prouidence 
of the Almighty to temper the same, that by the 
benefit of Margie or Marie (as it is commonly called) 
it may be made not onely equall in fertility with the 
other grounds of the Shire, as well for Corne as 

* The Inrichment of the Weald of Kent, 1625. 




Grasse, but also superioiir to the more and greater 
part of the same." The antiquity of this process was 
demonstrated " by the innumerable Marie pits digged 
and spent so many yeeres past, that trees of 200 or 
300 years old doe now grow upon them." 

Paring and burning was also a common method of 
amelioration. The top two or three inches of soil 
were pared off, collected into heaps and burned. (The 
agricultural labourer has a wonderful facility for 
setting fire to the most unpromising material.) The 
process was so managed that the clay was not baked 
into brick, but sufiiciently heated to disintegrate it 
and partially decompose the organic matter. Then 
the heated material was spread over the land and 
was found to be very productive. In some of the 
eastern counties Blith's draining method was early 
applied ; thus Vancover in his Report on the Agri- 
culture of Essex in 1795 refers to much of the stiff 
clay as being "hollow drained" and dressed with 
chalk, after which it continues to give good crops for 
20 years or more. Wheat and beans have always 
been the most suitable crops for clay farming, and 
a common Essex rotation was : fallow, wheat, beans, 
wheat, or, where greater diversity was required, 
fallow, oats or barley, clover and rye-grass, wheat, 
beans. But the implements were cumbrous ; in bad 
weather it might prove impossible to get the crops in, 
so that a season would sometimes be missed. So 


long, however, as wheat remained high in price 
occasional losses of this kind were not serious to the 
farmer. But the labourer suffered, for he found him- 
self practically out of work all the winter, excepting 
when the ground happened to be frozen sufficiently 
hard to enable the dung carts to travel, or when 
hedging and ditching had to be done. 

Next came a period of depression from 1813 to 
1836 when much of the clay land became derelict. 

A new era of prosperity opened with the reign of 
Queen Victoria and gradually the land was taken 
into cultivation. A delightful account has been pre- 
served^ of the reclamation during this period of a 
cold, wet, clay farm. " Every incoming tenant took it 
at about half the previous rent ; dabbled about for 
a year or two like a duck, and retired — *lame.' It 
was but a simple equation — a very simple one — to 
say when the rent would come to zero." The water 
did not drain away, "it would stand, day after day, 
and week after week, and month after month, shining 
along the serpentine furrows, as if it never, never, 
never would go again. And the only wonder was 
when or how, or by what bold amphibious being the 
ridges had ever been raised, which it intersected, 
like a sample series of Dutch canals and embank- 

1 Talpa^ or The Chronicles of a Clay Farm, by C. Wren Hoskyns, 


A careful survey by the owner showed the ap- 
parently level area really had a fall of nine feet, so 
that systematic drainage was quite possible. This 
was clearly the first step to be taken. Calculations 
were made to show the amount of fall that must be 
obtained in each field, and the men were set to work 
to open up the trenches, so that the levels might be 
taken previous to laying in the pipes. With so small 
a fall it was necessary that the work should be 
accurately done. 

But the whole idea was new to the labourers. 
They had never seen telescopes and levels and they 
were convinced that the farm was level and un- 
drainable. "The morning after my head-drainer 
had commenced operations I found him hard at 
work cutting a drain about eighteen inches deep, 
laying in the tiles one hy one, and filling the earth in 
over them as he went!..! began something in this 
way — ' Why, my good friend, what on earth are you 
about ? Didn't I tell you to lay the drain open from 
bottom to top, and that not a tile was to be put in 
till I had seen it and tried the levels? '...Every inch 
of depth was of value at the mouth of so long a 
drain. * Three feet deep at the outlet' was the 
modest extent of my demand ; and there I stood 
watching the tiles thrown in p61e-mele to a depth of 
eighteen inches, which I was given to understand 
was * about two feet ' with as cool an indifierence to 


the other foot, as if Two and Three had been recently 
determined by the common assent of mankind to 
mean the same thing. 

" * But I must have it three feet deep.' 

" ' Oh, it's no use : it'll never drain so dip as that 
through this here clay.' 

" * But I tell you it must be. There can be no fall 
without it.' 

" * Well, I've been a-draining this forty year and 
I ought to know summut about it.' 

"At that instant my eyes began to open to the 
true meaning of those 'practical difficulties' which 
the uninitiated laugh at, because they have never 
encountered them ; and the man of science despises, 
who has said to steam, water and machinery 'do this,' 
and they do it, but has never known what it is to 
try and guide out of the old track, a mind that has 
run in the same rut ' this forty year and more '." 

By a skilful appeal to the old man's vanity the 
matter was rectified and the drains properly laid. 
Then came the next improvement — throwing down 
the high ridges in which the land had formerly been 
laid, and flattening out the field, so that the imple- 
ments could work more easily. This met with even 
more serious opposition, and a long struggle ensued 
with the collective experience of the district. " My own 
working bailifi^ headed the attack Avithin the camp ; 
while a neighbouring clergyman led on the foe from 


without, evidently viewing the heresy in a serious 
light, and myself as a fit subject for an auto da f4. 
The conclusion of our last skirmish was too good to 
be lost to posterity. I entered it verbatim in my 
farm memoranda. 

" 'But tell me in earnest Don't you mean to ridge 
up that field again ? * 


" * What, you mean to lay it Flat ? ' 


" ' In the name of Goodness, Why ? ' 

" ' Because the name of Goodness — made it so.* 

" If I had suddenly assumed some demoniacal form, 
and then, leaving a train of smoke and brimstone, 
vanished, with a clap of thunder, from before the eyes 
of my catechist, I do not think his face would have 
assumed a greater expression of resourceless and 
complete astonishment ^" 

Next, the material thrown out from the drains 
was put on the surface of the land — an operation 
that was regarded as the crowning act of folly and 
brought up the wise men from far and near to look 
and scofi*. 

Lime was now put on. 

1 The "worthy clergyman's astonishment was not wholly unreason- 
able because in levelling the ridges a considerable amount of very 
unkindly subsoil must have been exposed, which would only slowly 
weather down into a decent soil. 


Then the small fields had to be made into bigger 
ones : hedges were grubbed up and the banks were 
thrown down, much to the disgust of the local fox 
hunters and rabbit shooters. 

Turnips were then sown — they had never pre- 
viously been grown on the farm — and they were ferti- 
lised with guano which was then just coming into the 
country. This evoked much comment from the local 
wits, but the crop was magnificent, being far the 
best in the countryside. "It was stared at and 
stared at again, as a sort of conjuror's trick which 
^You couldn't do again.' 'Wise men shook their 
heads and held their tongues at it. Nobody would 
have been at all surprised if, on going to the field 
some fine morning, he had found it altogether 
vanished, like faery money, as quickly as it came : 
and as the roots swelled and swelled into confirmed 
substance and reality through September and October, 
the silence about it became perfectly portentous.... 
Where did the crop come from ? How did it grow ?. . . 
Surely it must at any rate be but a fraud upon the 
land after all ; and the next crop would show the 
different results of real manure and a mere stimulant. 
This was the point to which ojnnion at last settled 
down. * We'll wait and see ' was the final determina- 
tion expressed." 

The big crop of turnips enabled sheep and cattle 
to be kept, and their manure helped to enrich the 


land and to keep the fertility up to the new level 
to which the drainage and liming had brought it. 
But the introduction of live stock had far-reaching 
economic effects also : it afforded employment for 
the labourers during the winter, and it had a steady- 
ing influence on the farm receipts. For when the 
price of wheat was low that of meat was high, and 
vice versa, a relationship that crystallised into the 
saying, " Up corn, down horn." 

In this way many clay farms were made fruitful ; 
lime and chalk once more came into use, and the 
introduction of artificial manures and of concen- 
trated feeding stuffs for the animals contributed 
largely to the increase in crop production that was 
taking place. 

But the tide of prosperity began to turn, and in 
the late 'seventies a run of bad times set in, ruining 
many farmers and throwing out of cultivation much 
of the land that had been reclaimed. It lay for 
years neglected and covered with grass and weeds ; 
its only use was to afford a little poor grazing for 
live stock. It was certainly gaining fertility and 
increasing its stores of nitrogenous organic matter, 
but it afforded little sustenance to the farmer. 
Essex, which had in the 'sixties been extremely pros- 
perous, looked like becoming derelict : other clay 
counties fared no better. Many of the farmers who 
survived met the crisis by laying down their land to 

R. 7 


gi'ass, dismissing their labourers and reducing their 
working expenses to a minimum. Great was the 
distress all round. Tales of those days are still told 
in the villages, and are indeed often the only in- 
formation possessed by the well-meaning agricultural 
reformers who dwell in the cities. 

Part of the agricultural depression was due to the 
opening up of the western states of Canada, and part 
of the recovery was, in return, effected by the labour- 
saving machinery invented and made out there. 
Under the older system in vogue in 1890 the cost 
of harvesting wheat came to 27s. to 305. per acre 
on a certain large corn farm : with the new bindera 
the cost was reduced from 1897 onwards to 16s. to 
18s. per acre on the same farm. Further, new 
methods began to come in. Essex was invaded by 
good Scotch farmers who were untrammelled with 
any views as to the necessity for growing wheat and 
beans, and turned instead to dairy produce and 
potatoes. For miles round London and other large 
cities dairying has saved the situation and once more 
brought into use land that had gone derelict. Else- 
Avhere (e.g. in parts of Leicestershire) cattle are 
bought and fattened, while costs of production are 
cut down by the introduction of labour-saving devices 
and by skilful management. The introduction of the 
mangold into British agriculture has been a great 
boon to the clay farmer ; this crop is much more 


reliable than swedes on clay land and, together with 
cabbage, which also does well, affords valuable suc- 
culent food to the animals, while on the lighter fields 
of the farm swedes can also be grown. Much food 
has to be purchased — brewers' grains and cotton cake 
being special favourites — and this contributes to the 
fertility of the land. Large quantities of manure 
are also imported, for mangolds respond perhaps 
more than any other crop to liberal treatment, and 
are found to yield most profit when well manured. 
Thus the fertility of the arable land is being pushed 
well up. But the mainstay of clay farming is the 
grass land. Grass is the cheapest and easiest crop 
to raise and is steadily gaining ground at the expense 
of the arable crops. Temporary pastures figure 
very prominently, particularly in northern systems 
of agriculture. Magnificent permanent pastures are 
found on some of the better clays of Leicestershire, 
and on the low-lying alluvial flats round the estuaries 
of some of the rivers and elsewhere; some of these 
with very little trouble will carry and fatten live 
stock. Over large areas, however, the grassland is 
poor, but it is now receiving considerable attention. 
Although for years it often carried nothing more 
than a poor, thin growth of weeds and grass it really 
did not need any very great outlay to be considerably 
improved. A dressing of 10 cwt. of basic slag per 
acre has often a wonderful effect in increasing the 



growth of clover and producing a more nutritious 

Trouble still arises from the presence of epizootic 
diseases in animals grazing on clay land, but this will 
no doubt be overcome as fuller knowledge is gained 
of the fauna of the soil. Often, however, the drainage 
is faulty. Over much of the Midland clay area the 
drains were laid in the middle of the last century 
at a depth of 4 ft.; this is now kno^vn to have 
been too far down. Here the trouble arises from the 
slowness with which the rain water gets away. The 
drains should, therefore, only be placed about 2^ feet 
deep. In many cases also the grassland needs plough- 
ing up and resowing with a suitable mixture. Finally, 
many clay farms need a good dressing of lime or 
chalk over the whole land, arable and grass alike. 

Once the grassland is improved it commonly gets 
well treated ; manure is put on if it is cut for hay, and 
concentrated food is supplied to the animals put out 
to graze on it. The grassland is consequently main- 
taining or increasing its fertility. At the present 
time, therefore, clays within reach of cities have dis- 
tinct possibilities. Those further off, however, are 
frequently in a poor state and are more famous for 
the fox-hunting they afford than for their agriculture. 
Sometimes summer milk is produced to be sold to 
the cheese makers, but this trade is at a standstill in 
winter ; sometimes also young store stock are raised 


to be sold off to the better farms. For it is a general 
rule that the raising ot young store stock is most 
suitable to the man who farms poor unimproved land 
without much capital, while diiilying and fattening 
are most suitable to the man who is going in for high 

The clays have probably never been managed on 
sounder lines than they are at present, but the lesson 
of history is absolutely clear ; these soils are very apt 
to suffer in bad seasons and to ruin their occupiers 
in times of depression. A good margin must therefore 
be allowed for contingencies. Especially ought small 
holders and beginners to remember that the profit 
these soils can be shown to yield over a run of good 
seasons changes with disastrous suddenness to serious 
loss as soon as bad times come. 



Starting once more from the fertile loams, a 
succession of soils can be traced, getting lighter and 
lighter and finally ending in the coarse material of 
heaths and sand-dunes. Thus we can begin with 
clay wastes, work through the fertile loams, pass on 


to cultivated sands and finally end in sand wastes, 
and find all the way gvadual transitions with never 
a break to mark off the different classes of soils. 
A typiciil sandy soil is. ^ust as characteristic as a 
typical clay, but it equally denes rigid definition. 

In many respects sand is the opposite of clay in 
general properties. Sandy soils have little power of 
holding water and therefore dry very readily ; they do 
not long remain wet even after heavy rainfall. They 
are not sticky. The rock from which they are formed 
is generally somewhat hard, and so it has often hap- 
pened that they have suffered less erosion than the 
clays, and have not, like the clays, been hollowed out 
into broad valleys. The ease with which water per- 
colates through sand has led to the washing out of 
much of the soluble material, so that little is left 
except hard insoluble mineral grains which furnish 
but scanty food for plants. 

Agriculturally the sands are a very mixed group. 
Their small power of retaining water is a serious 
disadvantage, partly because they become liable to 
drought, and partly also because of the ease with 
which manurial substances are washed away and 
lost. A good many of these soils happen to lie in 
relatively low situations and to receive underground 
water from the land above; these are often suffi- 
ciently supplied with water for all crop purposes. 
Others lie rather too high to enable the underground 


water to be utilised. Thus the value of a sand 
depends very much on its situation. A soil that 
is fairly uniform may be fertile in one place where 
water is available, but infertile in another not far 
off, where the water is out of reach. Where cultiva- 
tion is possible it is very easy : the land can be 
worked almost directly after rain, seeds can (and in 
fact must) be sown early in the year, and crops ripen 
quickly and easily. 

The sands that most resemble the loams — the so- 
called sandy loams — have usually been in cultivation 
as far back as any record goes. The lighter sands 
have only slowly been taken up, and the process is 
not yet complete, considerable areas being still left 
as waste. 

The stretch of country surrounding Fakenham and 
Wells in Norfolk is classical ground for the student 
of agricultural history. It was to Raynham, near 
Fakenham, that Charles, second Viscount Townshend, 
retired in 1730, after his political life was over, and 
began those farming experiments that were destined 
profoundly to influence our methods of husbandry. 
At the outset the land was a barren sandy waste. 
His first step was to apply marl which considerably 
increased its productiveness. This, however, was no 
new discovery ; marl was well known in Norfolk, 
although it had long fallen into disuse. Lord 
Townshend's great advance was the clearness with 


which he recognised the conditions that make for 
fertility in sandy soils. Owing to their small reten- 
tive power they have to receive frequent dressings 
of manure, and this course is only possible where a 
considerable number of animals are kept. Means 
therefore had to be designed for combining animal 
husbandry with crop growing — two branches of farm- 
ing which in the past had often been found mutually 
antagonistic. Lord Townshend's method was to grow 
turnips on the large scale, and then allow the animals 
to eat the crop in situ, so that their manure might 
fertilise the land for the next crop and their treading 
might consolidate it and so improve it as a seed bed. 
After turnips a crop of barley was taken and after 
this a crop of grass and clover, part of which could 
be cut as hay to supply food for the animals during 
winter, and the remainder eaten in the field by the 
animals in order to fertilise the ground for the wheat 
crop. Then turnips were taken again. The clover 
increased the stock of soil nitrogen and insured the 
permanency of the system so far as nitrogen is con- 
cerned. The plan was thoroughly sound and entirely 
successful; a manuring crop was taken, and then a 
cereal crop, then a second manuring crop and then 
another cereal crop. Both animals and crops 
flourished. So good is the plan that it survives to 
this day under the name of the Norfolk rotation, 
and many progressive farmers still use it with but 


the small modification that they often grow two corn 
crops in succession after the turnips. 

But it commonly happens in the history of agri- 
culture that improvements are adopted only very 
slowly, and Townshend's improvements were no 
exception to the rule. Certain difficulties also arose 
which Townshend did not overcome. Turnips were 
found to be liable to attacks of a minute beetle, 
Phyllotreta nemorum, commonly known as the Fly, 
which in dry weather sometimes almost destroyed 
the crop and left the animals without any food for 
the winter. Red clover (the ordinary variety grown) 
will not always grow every fourth year, but sometimes 
fails after the second or third course for some reason 
which is still obscure. Thus under the combined 
attacks of Turnip Fly and of Clover Sickness the 
farmer might find himself with a number of animals 
on his hands and no food for them, an awkward 
predicament from which he rarely extricated himself 
without considerable financial loss. 

Fortunately another public-spirited landowner in 
the same district came forward and continued the 
experiments. Thomas William Coke, afterwards 
Earl of Leicester, inherited in 1776 his uncle's estate 
at Holkham, about twelve miles north of the scene of 
Lord Townshend's labours. The country was poor 
in the extreme. "All you will see," said old Lady 
Townshend to young Mrs Coke as she was going for 


the first time to her new home, " will be one blade of 
grass and two rabbits fighting for that." Coke's bio- 
grapher and great-granddaughter, Mrs Sterling, thus 
describes it\ "When Coke came into the property 
the whole district round Holkham was little better 
than a rabbit warren, varied by long tracts of shingle 
and drifting sand, on which vegetation, other than 
weeds, was impossible.. . .Indeed throughout the county 
of Norfolk the agriculture was of the poorest descrip- 
tion. Between Holkham and Lynn not a single ear 
of wheat was to be seen, and it was believed that not 
one would grow. All the wheat consumed in the 
county was imported from abroad. And, meanwhile, 
everything that ignorance could do was done to 
impoverish further an already miserable soil. The 
course of cropping where the land would produce 
anything was three white crops in succession, and 
then broadcast turnips. No manure was ever pur- 
chased. The sheep were a wretched breed, and, 
owing to the absence of fodder, no milch cows were 
kept on any of the farms." Coke does not seem to 
have begun experimental farming out of any abstract 
desire for knowledge ; he was led to it by the obstinacy 
of an old-time farmer named Brett. The lease under 
which this man held his farm had fallen in and was 
under discussion for renewal; the original rent had 
been eighteen pence per acre ; this was subsequently 

1 Coke of Norfolk and his friends. London, 1908. 


raised to three and sixpence, and Coke now wanted 
five shillings. " Mr Brett jeered at the suggestion," 
continues Mrs Sterling, "and pointed out that the 
land was not worth the eighteen pence an acre 
originally paid for it. This was suflScient for a man 
of Coke's temperament, he immediately decided to 
farm the land himself." 

No adequate history of Coke's agi-icultural work 
has been written^, but fi-om 1778, when the little 
incident just mentioned took place, down almost to 
the time of his death in 1842, he continued to make 
advances in the management of sandy land and dis- 
seminated his results at the great annual gatherings, 
the " sheep shearings," which for 43 years he held at 
Holkham. Realising the beneficial effects of grass 
and clover on the land, he left these crops growing 
for two, three, or even four years, thus adding to the 
nitrogenous organic matter of the soil, besides getting 
supplies of hay for the animals. Marl was applied 
in the first year at the rate of 80 to 100 loads per 
acre and left to wash into the land as long as the 
grasses stood there. When the land was ploughed 
up wheat was sown. Usually the amount of farmyard 
manure was insufficient for this crop, at any rate in 
the early days of the improvements, and manure had 
to be purchased. Rape cake (an old fertiliser in 

* Some account ia given in Dr Eigby's Holkham, its Agri' 
culture^ etc., 1816. 3rd edition, enlarged, 1819. 


Norfolk, brought in from Ireland and from the English 
mills) was therefore applied with excellent results: 
it cost £5 per ton and was used at the rate of 5 or 
6 cwts. per acre : later on, however, the price rose 
considerably. After wheat, turnips were grown, and 
then barley followed by grasses as before. Thus the 
rotation was that of Lord Townshend except that 
the grasses were left growing for several years, and 
peas appear sometimes to have been sown after the 
grass was ploughed up and before the wheat crop 
was taken. Alongside of this improvement in cul- 
tivation he elFected great improvements in the live 
stock of the district. He compelled his tenants to 
adopt a proper rotation and induced them to pur- 
chase good animals. So successful were his eflPorts 
that as early as 1784 Young states that "Mr Coke 
resides in the midst of the best husbandry in Norfolk, 
where the fields of every tenant are cultivated like 
gardens." There was a great surplus of produce, 
wheat and live stock were sold and the whole district 
became very prosperous. 

Tlie difiiculties inherent in the Norfolk rotation — 
turnip fly and clover sickness — now engaged his 
attention. Although he did not suimount either 
difficulty (no one has done so even yet) he got over 
them by increasing his range of crops so that he 
should not be wholly dependent on turnips and 
clover. Instead of having the whole of the land 


in four crops he devoted some of it to other fodder 
plants. Sainfoin in particular proved valuable; it 
yielded considerable quantities of nutritious hay for 
winter, and, being a leguminous plant, it greatly en- 
riched the soil in nitrogenous organic matter. Tares 
also were sown; some in October or November, some 
in April and May, to alFord more green food to the 

Later on he grew mangolds, cocksfoot, potatoes, 
and he made experiments with other fodder crops. 
He purchased oil cakes for his animals, and thus 
not only fattened them more rapidly but also in- 
creased the amount of fertilising material in the 
manure. In this way he imported fertility fi^om other 
districts to his own, a process which has now become 
a regular part of British husbandry. Thus sheep and 
cattle were the central feature of the farm as in Lord 
Townshend's system, but Coke increased the margin 
of safety by having certain areas of other fodder 
crops not liable to the same ills as clover and turnips, 
so that if one set of troubles intervened he would 
still have a reserve of food for his animals. 

Little has been added to our knowledge of the best 
methods of farming sandy soils, and in all essentials 
our best present day methods are practically the same 
as these. The reclamation of the sands was now 
within the power of any landowner and was soon 
taken in hand in many districts. The Duke of 


Bedford reclaimed much of the sand at Woburn^ 
and before long the old parish turbary was waving 
with corn. An example of a later reclamation is 
afforded by Delamere Forest, Cheshire. The marl 
pits having been formed and opened, a tramway was 
laid from the pits to the land. Dressings of marl 
were given varying from 100 to 180 cubic yards per 
acre at a cost of £7 to £10 ; in consequence the land 
which before marling was not worth 5s. per acre 
afterwards let at £1. 10s. per acre I The light sand 
of the Pays de Waes, lying between Antwerp and 
Ostend and traversed by the Waesland railway, has 
also been reclaimed by the application of clay or 

Sometimes, however, the barrenness of a sandy 
soil is due to a layer of rock or a "pan" lying near 
the surface and interfering so seriously with the move- 
ments of the soil water that proper plant growth can- 
not take place. In such cases the only possibility is 
to break up the rock and pick it out, a laborious 
enough process even now when steam implements are 
available, and still more so in the early days. An 
example is furnished by Coxheath, an area of some 
900 acres near Maidstone. This used to be waste 
land, but in 1814 an Enclosure Act was obtained. 
The gi'ound was then trenched and the layer of rock 
broken and removed. Over part of the land no 

^ Journal of the Royal Agricultural Society ^ 1864, p, 369. 




c , • t 

( r ( c 


further treatment seems to have been necessary, and 
good crops were at once obtained after a reasonable 
outlay on manure; so permanent was the improve- 
ment that the land still lets for £2 per acre per 
annum. Other of the land, however, was very poor 
and required heavy manuring before it became 
productive. Most of the land thus reclaimed was 
divided among the lords of the manors and others 
possessing rights of common, of cutting turf, etc., 
while part of the remainder was sold to defray the 
expense of reclamation ; the stone that was taken 
out lay stacked along the roads in enormous quan- 
tities, and people thought it never could be used, 
but subsequently it was all required for making up 
the Weald roads. The reclamation went on between 
1814 and 1818, but was not completed: only recently 
has the whole of the land been taken in, the last 
surviving piece of waste having proved a considerable 
nuisance because of the gipsies that encamped there. 

The system of managing sandy soils introduced by 
Townshend and Coke is, as we have seen, a combina- 
tion of crops and live stock : nitrogenous compounds 
are added to the soil by clover or other leguminous 
crops, and by purchased oilcake: lime, potassium 
salts, phosphates are also added : the crops so grown 
are (with the exception of grain) fed to animals to 
make manure for more crops. Crops and live stock 


are thus mutually interdependent, and any break- 
down on the part of either causes the collapse of 
the system. 

Another method of dealing with sandy soils has, 
however, long been practised. The ease with which 
they are cultivated and the earliness at which their 
crops ripen marked them out long ago as eminently 
suitable for market garden produce. The light loams 
of East Kent have grown fruit since Tudor times. 
Vegetables and fruit were long ago grown on the 
light soils round London, and the practice was ex- 
tending by the end of the eighteenth century even 
in places as remote as Suffolk; stable manure was 
barged from London to Manningtree and sold at lOs. 
for a five-horse load at the quay, while carrots were 
grown on the sandy soils and sent back to London. 
This system has now developed very extensively, 
and now-a-days considerable areas of sand produce 
potatoes, vegetables or fi'uit to be sent off to the 
cities, and are fertilised with stable manure and 
other refuse brought back from the cities. 

A third system is in use. The introduction of 
artificial manures has enabled the sand farmer to 
be wholly independent either of live stock or of city 
manures for keeping up the fertility of his soil. The 
classical instance of tliis type of management is 
afforded by the Lupitz estate at Altmark, Saxony. 


When Herr Schultz came into possession in 1855 
the land was largely a barren heath, yielding crops 
only at considerable expense. He soon observed, 
however, that lupins grew well provided the rainfall 
was sufficient (the average fall was 27 inches), and 
also found that they enriched the soil in nitrogenous 
organic matter and fertilised the next crop. His 
method as finally worked out was essentially as 
follows : leguminous crops were gi'own and fertilised 
with mineral manures — lime, phosphates and potas- 
sium salts — in order to induce considerable plant 
development and therefore considerable nitrogen 
fixation. Some of the crops were cut for hay, but 
in the main they were ploughed in, thus adding to 
the soil the nitrogenous organic matter of the stems 
and leaves as well as of the roots. Crops thus 
ploughed in are called green manure. An acre of 
green crop was found to furnish roughly as much 
nitrogen as 10 to 15 tons of farmyard manure, and 
this, taken in conjunction with the nutrients added 
in the artificial fertilisers, sufficed to yield large crops 
of grain and potatoes. Thus, without purchasing 
nitrogenous manures (which are very costly), and 
without keeping much live stock, Schultz was able 
by periodical green manuring enormously to increase 
the productiveness of his land. This extremely valu- 
able method has been much adopted in Germany. 
Where high priced crops are grown it may prove 

B. 8 


more profitable to purchase nitrogenous manure 
instead of making it through the agency of legu- 
minous crops. Dr C. S. Edwards adopted this course 
in his recent successful reclamation of a considerable 
area of derelict sand at Tangham, Capel St Andrew, 
Sufiblk. The heather and bracken having been 
eradicated, 20 to 25 loads per acre of " crag " (finely 
divided shells, silts, etc., rich in calcium carbonate 
and occurring in deposits just below the surface) 
were put on at a cost of about £1 to £2 according 
to the distance from the pit, and then the land was 
broken up. It was usually necessary to do this with 
the steam cultivator because the large number of 
rabbit holes made the ground dangerous for horses. 
After about four to eight cultivations the land was 
sufficiently level, the rabbit holes filled and the weeds 
killed : this cost up to £2 per acre. A second cragging 
is now advantageous. The crops grown are wheat, 
oats, potatoes, blue peas (sold dried for human con- 
sumption) and carrots; for the working horses and 
the pigs a patch of lucerne is grown. As everything 
is sold ofi* and no stock is kept (except pigs to 
consume waste potatoes, etc.), it is unnecessary to 
adhere to any rigid rotation, and the farmer can 
grow whatever promises to yield most profit. The 
artificial manures used are : for carrots and potatoes, 
1 cwt. of muriate of potash and 1| cwt. of bone meal 
applied in April, IJ cwt. each of nitrate of soda or 


lime and sulphate of ammonia applied in two dressings 
later on ; for wheat or oats, 1 cwt. nitrate of soda or 
lime or sulphate of ammonia, J cwt. sulphate of 
potash and f cwt. of bone meal; for peas, ^ cwt. 
sulphate of potash and f cwt. bone meal. Such little 
dung as is got goes on the lucerne or on the wheat. 
Careful cultivation is necessary to preserve a fine 
mulch, whereby the soil retains its moisture, and also 
to keep down weeds which are apt to be a con- 
siderable nuisance: even the freshly-broken ground 
covered itself with spear gi'ass (couch), makebeg 
(spurry) and sorrel, while later on iron weed (poly- 
gonum), pansy, cranesbill and others came in. 

The great advantage of the system is that it can 
be worked with but little capital and at a minimum 
of risk. It is therefore well adapted for small holdings, 
for which purpose, indeed, it was devised. The returns 
have been very satisfactory : the sales have averaged 
£6 to £7 per acre, while a rent of 15s. per acre was 
found to pay 5 per cent on the cost of reclamation, 
5 per cent, on a sinking fund, and also the rates and 
the rental imposed by the superior landlord. 

The occupier of a sandy soil has therefore several 
possibilities open to him. If he can command capital 
he can go in for live stock and work on the Townshend- 
Coke system. If he prefers cultivation he can go in 
for intensive market gardening. If he has little or 


no capital he can work on Dr Edward's lines and 
gi'ow the more highly priced of the ordinary crops 
by the use of suitable artificial manures. 

An instance may be given of the modern develop- 
ment of the Townshend-Coke treatment of light sandy 
soils. The farm is on a light sand in Surrey, and is 
so dry in summer that satisfactory grass cannot be 
grown ; no sheep are therefore kept during the warm 
months of the year. Sheep are bought in from Sussex 
and the West Country in September and are fattened 
on the land during the winter; they are sold as 
fast as they are ready and are all cleared out by the 
end of May. Considerable amounts of green crops 
are grown for them, including trifolium, green rye, 
rape, kale, turnips, swedes, and a mixture of clover 
and rye-grass, whilst large quantities of oil-cake and 
purchased grains are also supplied. The land thus 
becomes well fertilised, and is now sown with spring 
oats, which are often succeeded by a crop of malting 
barley. Then a mixture of rye-grass and clover is 
sown to afibrd hay in June and green food in 
September. The land is then ploughed up for winter 
wheat, and a dressing of London stable manure is 
given so as to ensure a satisfactory crop of sti*aw 
which is sometimes a very saleable commodity. Re- 
course is had to artificial manures and periodically to 
lime in order to maintain fertility at a high level. 

Instances of the market garden method occur on 


almost any sandy soil within access of a large city, 
especially where one man happens to have prospered 
and so given the locality a reputation. No general 
rules can be given about the management : the 
successful grower generally keeps his land continu- 
ously cropped and carefully watches the markets so 
as to grow those things likely to yield most projfit. 
The following is an actual example. The grower is 
near to London and has access to a riverside wharf; 
he buys as manure City refuse, cleanings from 
cattle steamers, unsold lots of stable manure, con- 
demned fish, and any odds and ends of manurial 
value. He also takes for a consideration some of 
the local sewage. His ground is never idle: early 
potatoes, onions, sprouting broccoli, peas and other 
crops succeed each other without delay, odd comers 
are filled up with early carrots, radishes, etc, all the 
crops are carefully nursed so as to be ready for market 
while prices are still high, i.e. before other people 
have their produce ready. Much fruit is grown, pigs 
are kept in the orchards to do the cultivation and 
devour unsaleable crops. Considerable advantage is 
taken of labour-saving devices. The grower's success 
does not stop at production, but extends also to the 
business side. Market garden produce is sold to 
salesmen in the large markets who in turn have to 
keep contracts with large customers. This grower, 
being eminently successftd and dependable even in 


bad seasons, is therefore a useful stand-by for these 
people, and receives respectful consideration at their 

Considerable areas of sand, however, still lie waste 
in the agricultural sense. But they are not neces- 
sarily unproductive from other points of view. Some 
of the most delightful scenery in our country is to be 
found on the sands; even the most ardent reformer 
would hardly wish to root up the New Forest, the 
Bournemouth pine woods, the Wareham and Dor- 
chester heaths, and substitute fields of turnips and 
sheep. Elsewhere, also, golf links have proved 
extremely remunerative. Considerable tracts of sand 
are given up to game. And there lies one of the 
difficulties of the situation. For game sometimes 
plays a very large part in the economy of the 
countryside, and may dominate pretty completely 
the movements both of man and of beast. There 
are parts of East Suffolk where the cottagers' cats 
have to live chained up like yard dogs in order to 
be safe from the gamekeepers' guns, while extensive 
damage is often done to the crops by birds, hares and 
rabbits. And so it happens that the man who under- 
takes to reclaim derelict sand and bring it into culti- 
vation has not only to overcome the natural difficulties 
of the problem, but also to come to terms with the 
game preservers. 

Lastly, the sand dunes are now beginning to 


attract attention. It has long been the practice to 
plant these up with conifers or other suitable trees, 
but in New Zealand dune pastures are produced 
instead. Marram grass {Ammophila arundinacea) 
is first grown to fix the sand, and then the tree 
lupins (Lupinus arbor eus)] finally pasture grasses 
are sown, especially such as, under the prevailing 
conditions, make considerable root and so add to 
the stores of soil organic matter. 



We have already dealt with the reclamation of 
the fens, we must now turn to the wholly distinct 
case of the moors. Speaking generally the moorland 
tracts of the country lie in high regions of considerable 
rainfall : the fens, on the other hand, are low lying 
and have a much smaller rainfall. When the fens are 
drained they become at once fit for cultivation and 
yield considerable quantities of potatoes, wheat and 
other crops. But the high moors do not : their soil 
is fundamentally difierent ; their rainfall is too high 
for satisfactory crop production ; and owing to their 


great altitude the winters are so severe that any 
kind of farming is attended with risk and difficulty. 

Low-lying moor and peat districts may escape 
these climatic disadvantages and then their reclama- 
tion becomes simply a matter of soil treatment. 
Chat Moss in Lancashire affords an instance : it was 
first drained to remove excess of water and then 
heavily treated with town refuse from Manchester 
which enabled it to yield crops. An arrangement of 
this sort is mutually advantageous to city and country 
so that the expense can be distributed. But else- 
where the carriage of bulky extraneous matter 
becomes too costly to be borne entirely by the 
reclaimed land, and more concentrated ameliorating 
agents become necessary. 

The problem has attracted considerable attention 
in Germany and Sweden and is under investigation 
at the special experiment stations at Bremen and 
Jonkoping. Enough has been done to show that 
treatment with artificial manures leads to profitable 
crop production, especially of rye, oats and potatoes, 
on drained land. These crops do not stand in great 
want of lime, and need only a few hundredweights 
per acre of potassic, phosphatic and nitrogenous 
fertilisers. But when it is desired to diversify the 
agriculture, liming becomes necessary and may prove 
costly. In some districts Hiltner has successfully 
solved the problem of growing leguminous crops, 


and has thus opened up the possibility of raising 
potatoes and cereals more cheaply than before. 

An interesting piece of reclamation went on under 
Nilsson's direction in Gothland, Sweden. More than 
30,000 hectares of the island consisted of barren 
swamps, and yet the soil was rich both in lime and 
in nitrogen. Nilsson showed that the limiting factor 
was lack of phosphorus. The ground was therefore 
drained and treated with phosphatic manure ; it then 
yielded excellent crops of corn, rape and sugar beet. 
Instead of depending wholly on foreign supplies of 
phosphates, investigation was made by Wiborgh of 
the iron ore occurring in Northern Sweden and known 
to contain calcium phosphate : a method of extraction 
was devised and quantities of this Wiborgh phos- 
phate were produced at Lulia. Subsequently a 
cheaper process was worked out by Palmaer. 

In the Isle of Ely phosphates are also found to be 
the limiting factor and dressings of superphosphate 
result in marked crop production ; elsewhere, however, 
potassium compounds constitute the limiting factor. 
A well-known example is furnished by the Momence 
experimental field set out by Dr Cyril Hopkins in 
Illinois, where potassic fertilisers yield good crops but 
other fertilisers prove useless. Dr Hopkins^ tells 
a pathetic story of a settler who spent years of un- 
availing labour on some of this black soil and did not 

1 The Story of the Soilf Boston, 1912. 


find out till too late the one thing needful. The man 
had brought his wife and children to see the heavy 
crop on plots treated with potassic fertiliser alongside 
of the miserable one on the untreated land. "As he 
stood looking, first at the corn on the treated and un- 
treated land, and then at his wife and large family of 
children, he broke down and cried like a child. Later 
he explained to the superintendent who was showing 
him the experiments, that he had put the best of his 
life into that kind of land. *The land looked rich,' 
said he — ^ as rich as any land I ever saw. I bought 
it and drained it and built my home on a sandy knoll. 
The first crops were fairly good, and we hoped for 
better crops ; but instead they grew worse and worse. 
We raised what we could on a small patch of sandy 
land, and kept trying to find out what we could grow 
on this black bogus land. Sometimes I helped the 
neighbours and got a little money, but my wife and 
I and my older children have wasted twenty years 
on this land. Poverty, poverty always. How was 
I to know that this single substance which you call 
potassium was all we needed to make this land pro- 
ductive and valuable ? '" 

The peats can be made productive if the climatic 
conditions are favourable. The agricultural utilisation 
of moorland depends mainly on this consideration. 
Obviously nothing but actual experiment would de- 
termine what could be accomplished, but at the 


present moment there seems little likelihood of any 
serious attempt being made in this comitry. For 
game has taken possession of the moorland, as of 
other land of low agricultural value, and having once 
got possession it is not easily displaced. A system of 
farming is in vogue that does not clash with game ; 
sheep are allowed to graze on the moorland, while 
the lower fields are kept in grass to furnish a little 
hay when needed The land thus yields two rents : 
the shooting tenant on a Lancashire moor may pay 
38. 6cL per acre, while the agricultural tenant pays 
2s., a total of 5s. Qd. Any agTicultural development 
that involved displacement of the game would have 
to yield a sufficiently increased rent over the whole 
moor or the owner would lose financially, and it is 
difficult to see on our present knowledge what agi'i- 
cultural system could do this^. Only a properly 
conducted experiment could decide the matter. 

1 An instance is given by Mr Pell in the Journal of the Royal 
Agricultural Society for 1887, where £24. 7s. 6d. was spent per acre 
in reclaiming a moor, and the increased rental only amounted to 
Bs. 2d. per acre. 




We can now sum up the general conclusions to 
which the previous chapters lead. 

The problem of making a soil fertile consists in 
finding out first what conditions the plant requires 
for its proper development, and then altering the soil 
as far as possible to make it meet these requirements. 
If the discrepancy between the actual and the ideal 
is too great the plant may be altered by the breeder 
in such a way that its new requirements shall be 
nearer the actual possibilities of the case. 

It is always most economical to select crops 
naturally adapted to the climatic and soil conditions, 
so that the gap to be bridged shall be small. Our 
problem is to alter the soil : in the first instance it is 
necessary to ascertain what the actual soil conditions 
are, and then to find which constitutes the limiting 
factor and to change that one. Probably another will 
now be found to set the limit : this must in turn be 
changed and so on until the limit is set by the 
incapacity of the plant to make further growth, and 
not by any soil factor. The responsibility of the soil 
investigator is now at an end, and the problem becomes 
one for the plant breeder. 


The soil conditions fall mainly into four groups. 

(1) The physical constitution of the soil determines 
the movement of water, of air, and of the plant roots. 

(2) The chemical composition shows the amount of 
food materials present, and whether there are any 
detrimental substances in the soil. (3) The micro- 
organisms of the soil are very mixed, some of them 
work up certain of the food materials into forms 
suitable to the plant and are therefore eminently 
useful, others are detrimental in various ways. 
(4) Extrinsic factors such as climate, situation of 
the soil, nature of the subsoil, etc., play an important 
part. Any of these groups may determine the fertility 
of a particular soil. To a certain extent, however, all 
of them are under control. The physical constitution 
is altered and made more favourable to plant growth 
by adequate cultivation, by addition of organic matter 
(e.g. farmyard manure) and if necessary of lime, chalk, 
marl, or clay. The chemical composition may be 
entirely altered so far as food constituents are con- 
cerned by adding appropriate fertilisers. Control of 
the micro-organisms of the soil is as yet in its infancy 
although a beginning has been made. The extrinsic 
factors are naturally less easy to change, but the 
subsoil may be altered by breaking any pan or rock 
layer, and drainage may be effected by suitable means. 

Soils do not fall into sharply defined classes but 
form a perfect gi'adation from intractable clays 


through the loams to light blowing sands. The loams 
are very fertile : the extremes of clay and of sand are 
infertile. But there is no sharp end-point : a number 
of soils near the limit may be productive under one 
system of management and not under another, and 
may be in cultivation during times of prosperity and 
derelict when prices fall. 

In applying these general principles to any par- 
ticular case a considerable amount of balancing of 
probabilities is necessary. Means taken to alter the 
physical condition of the soil may react on the micro- 
organisms, the chemical composition, etc., and vice 
versa. Above all, as the soil is cultivated for profit, 
economic considerations come in at every turn. Thus 
fertility problems are usually more complex than they 
appear at first sight, and require to be studied in the 
laboratory, the pot culture house and the field before 
they can be regarded as solved. 


Hall, A. D. The Soil. (MuiTay, 1911.) 

The Book of the Rothamsted Experiments. (MiiiTay, 1905.) 

Hopkins, Cyril G. Soil Fertility and Permanent Agriculture. 

(Boston, 1910.) 
Prothero, Rowland E. English Farming past and present. 

(Longmans, 1912.) 
Russell, E. J. Soil Conditions and Plant GrowtlL (Longmans, 



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t C I « 

( < < t. 


Air supply 30 

Ammonia, production of in soil 
16, 18 

Bacteria in soil 9 
Blith and drainage 76 

Calcium carbonate 6 
Chalking 82, 90 
Clay 4 

Clay soils 40, 86 
Clay soils, reclamation of 92 
Clover 56 
Coke's system 107 
Colmatage 82 

Conservation of moisture in soil 

Derelict land 46, 97 
Drainage 29, 76 

Edward's system 114 
Enclosures 52 
Energy stored in soil 8 
Exhaustion of virgin soils 46 

Fens, reclamation of 71 

Fertility limits 44 

Food, supply of for plants 32 

Game and the farmer 118, 123 
Grassland 99 

Hellriegel and WUfarth 21 
Hopkins, Dr Cyril 47 
Humus 8 

Lawes and Gilbert 13, 58 
Leguminous plants and nitrogen 

fixation 20, 57 
Liebig 58 

Live stock and fertility 104 
Loams 39 

Market gardening 112 
Marling 52, 80, 90 
Medieval farming 49 
Moorland, reclamation of 120 

Nilsson 121 

Nitrates in soil 13 

Nitrification 14 

Nitrogen cycle 25 

Nitrogen, evolution from soil 19 

Nitrogen fixation 20 et seq. 

Pan, removal of 110 
Partial sterilisation 26 
Phosphates and fertility 33, 58 



Plants, effect on soil 7 

Plants, suitability to soil con- 
ditions 41 

Potassium salts and fertility 34, 

Protozoa in soil 26 

Root range 35 
notation of crops 

61, 91, 104 

Sand dunes 119 
Sandy soils 38, 101 
Scbloesing and Miintz 14 
Schultz-Lupitz system 112 
Sheep and fertility 109 
Soil sickness 37 
Sourness 36 
Structure of soil 10 

Temperature of soil 30 
Townshend's system 103 
Tull's system 55 
Turnips and what they did 


Waesland 110 

Warington 13, 15 

Warping 82 

Waste of fertility 63 

Waste land 88 

Water supply 27 

Weathering 2 

Whittlesea mere, reclamation of 

Winogradsky 16 
Wychwood, reclamation of 66 

VAMBKIDOB: PRINTF.D by J. B. peace, M.A., at THR university PRK98. 

YB 51422 


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