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LAWES AGRICULTURAL TRUST.

Rothamsted Experimental Station,
Harpenden.

Annual Report for 1913

with the

Supplement

to the

“Guide to the Experimental Plots”

containing

The Yields per Acre, etc.

In every case the page, table, and plot numbers refer to the “Guide” 1913, it being
understood that no change is made in the manuring, etc., there described.

E. J. RUSSELL, D.Sc., Director.
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PRINTED BY D. J. JEFFERY, Vance, fags £8 P
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1914.

Digitized by the Internet Archive
in 2010 with funding from
University of Toronto

http://www.archive.org/details/report1913roth

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(G13 f MAYS 1914
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Biological aN Ves is anon
& Medical Soe oo $
Serials uae

LAWES AGRICULTURAL TRUST.

Rothamsted Experimental Station,

Harpenden.

Annual Report for 1913

with the

Supplement
“Guide to the Experimental Plots”

containing

The Yields per Acre, etc.

In every case the page, table, and plot numbers refer to the ‘‘Guide"’ 1913, it being
understood that no change is made in the manuring, etc., there described.

a WAY 8 19j4
HARPENDEN: FG. tates
PRINTED BY D. J. JEFFERY, VAUGHAN Roxb, ee au id ate:
1914. TS) i ¥ {yk TOY ig
s aa ill

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Laboratory Staff.

Pwector ... ve) fe RUSSELL, Eee
Lawes and Gilbert Laboratory. 9
Chemist ... ag He ae ~. NN; H. J. MILLER, Pema
PLC.
Hon.Rupert Guinness Chemist .. B. H.. RICHARDS, Eines
BELG,

Board of Agriculture Research Scholar W. BUDDIN, B.A.

= a - ji ]. A. PRESCOTT, Boe
Voluntary Research Worker ... ... H. SONNENFELD, M.S.Agr.
Chemical and General Assistant 1.) EB. GRER,
. A. OGGELSBY.
. A. BOWDEN.
. B. WESTON.

James Mason Bacteriological Laboratory.

Bacteriologist ... oT ... H. B. HUTCHINSON, PhD.
Carnegie Research Senolar es ... K. MACLENNAN, B.Sc.
Protozoologist ... uy au ... K. R. LEWIN, B.A.
Assistant ay ate Soe J SP WiEsem.

Soil Laboratory.

Goldsmiths’ Company’s Chemist 3+! ee FIORTON ee
= Physicist .. DrA, KEEN eo
Chemist for Gas Investigations ... A. APPLEYARD, M.Sc.
Board of Agriculture Research Scholar E. J. HOLMYARD, B.A.
Carnegie Research Scholar... ... W: WEIR, M.A, B.S
Organic Laboratory.

Chemist . aS re ... W.A. DAvis, B.Sc., ACG
Assistant Chemist ave Sey ... A. J. DaisH, B.Sc., AG

» » . G. C. SAWYER.

Botanical Laboratory.
Botanist ... oe ne a. ... WINIFRED E. BRENCHLEY,
DiSc,, BLES:
Assistant Botanist 5 ef ... HELEN ADAM, B.Sc.
Assistant ef ee or ... GRACE BASSIL.
The Farm

Manager ... Pe Nae ao, ia S.-J. K. Soaees:
Secretary ; oe Zee ... G T. DUNKLEY.,
Private Secretary i? ite ... GERTRUDE BATES.
Clerk oi ae eS B- ... W. WILSON.
Junior Clerk. <1, «a G.IPEARCE:
General Assistant and Caretaker we W, PEARCE.
General Assistant bie iis ... G. LAWRENCE.

Laboratory Boys iX- ae ... W.GAME AND F. SEABROOK.

3
INTRODUCTION

John Bennet Lawes was the founder of the Rothamsted
Experimental Station. He began experiments with various
manurial substances, first with plants in pots and then in the field,
soon after entering into possession of the estate at Rothamsted in
1834. In 1843 more systematic field experiments were begun, and
the services of Joseph Henry Gilbert were obtained as Director,
thus starting the long association which only terminated with the
death of Lawes in 1900, followed by that of Gilbert in 1901.

The Rothamsted Experimental Station has never been connected
with any external organisation, but has been maintained entirely at
the cost of the late Sir John Lawes. In 1889 he constituted a Trust
for the continuance of the investigations, setting apart for that pur-
pose the Laboratory (which had been built by public subscription,
and presented to him in 1855) certain areas of land on which the
experimental plots were situated, and £100,000.

By the provision of the Trust Deed the management is
entrusted to a Committee nominated by the Royal Society (four
persons), the Royal Agricultural Society (two persons), the Chemical
and Linnean Societies (one each), and the owner of Rothamsted.

Mr. A. D. Hall was appointed Director in 1902 and held the
position till he resigned in 1912, when the present Director, Dr.
E. J. Russell, was appointed. He brought about great developments,
re-organising the work, increasing the staff, and considerably extend-
ing the buildings and laboratories. In 1906 Mr. J. F. Mason, M.P.,
presented the Committee with £1,000 for the building and equip-
ment of the “James Mason” Bacteriological Laboratory, together
with a grant towards its maintenance. In 1907 the Goldsmiths’
Company made a grant of £10,000, the income of which is devoted
exclusively to the investigation of the soil. The Permanent Nitrate
Committee have also made a grant of £2,000 to the endowment.
The Society for extending the Rothamsted Experiments, founded
in 1904, collects donations and annual subscriptions to help carry on
the work.

During the year 1911 a scheme was published from the Board
of Agriculture for the encouragement of agricultural research with
funds provided by the Development Commission, and this scheme
established or assisted a certain number of institutes for fundamental
research, each dealing with one great branch of the subject. The
Rothamsted Experimental Station is recognised as the Institute
for dealing with Soil and Plant Nutrition Problems. In accordance
with this scheme a grant of £2,500 was made for the current year,
and it is expected that an annual grant of this amount will be made
to the Station in future. Certain scholarships have also been
instituted to provide the training in research work for men who have
already qualified in pure science and are desirous of taking up an
agricultural career. The holders of three of these scholarships are
now doing their work at Rothamsted. In addition, investigators from
other institutions periodically spend a certain amount of time in the
laboratories studying analytical methods or ways of getting over
difficulties that have arisen in the course of their work.

These developments have necessitated a considerable extension

of the laboratory and of the farm. For this purpose a grant of
£3,100 was given by the Board of Agriculture out of the Develop-
ment Fund, and an equal sum was provided by the Society for
Extending the Rothamsted Experiments. In 1911, 230 acres
of land were taken on a 77 years’ lease, and this, together with
the Trust land, gave a self-contained farm capable of being worked
with great advantage to the experiments. A new wing of the
Laboratory was opened on June 27, 1913, by the Rt. Hon. Walter
Runciman, M.P., President of the Board of Agriculture.

The condition of the main laboratory, however, gives cause for
considerable anxiety. It was built in 1855 and some years ago
began to reveal certain structural defects. The Committee are
advised that it may not last much longer, and steps have been taken
to raise the sum of £12,000 for the erection of a laboratory suited
to modern requirements. The opening of this laboratory is to
commemorate the centenary of the birth of Sir J. B. Lawes in
1814 and of Sir J. H. Gilbert in 1817.

The field experiments, which began in 1843, have on some of
the plots been continued without break or alteration up to the
present day; on the Broadbalk Wheat Field certain rearrangements
were made in 1852, in which year also the Barley experiments on
the Hoos Field began. The leguminous crops on the Hoos Field
were started in 1848, the experiments on Roots have been continued
on the same field since 1843, and on the same plan since 1856. The
grass plots began in 1856, and the rotation experiments in 1848.

It is impossible to exaggerate the importance of continuing the
experimental plots at Rothamsted without any change, as nowhere
else in the world do such extensive data exist for studying the effect
of season and manuring upon the yield and quality of the crop, and
for watching the progressive changes which are going on inthe soil.
Year by year these plots are found to throw light upon new problems
in Agricultural Science; in all directions they continue to provide
material for investigations upon points which were not contemplated
in the original design of the experiments, so that it is impossible to
foresee when and how they will not become useful and provide
indispensable material for the solution of problems undreamt of at
the present time.

The maintenance, however, of the old data throws a heavy
burden on the Experimental Station. There are 210 plots, and
every year 243 samples have to be taken with proper precautions
and put into store for future reference. In addition, many analytical
determinations are made. During the present and the coming season
complete soil samples are being taken for analysis, to enable a com-
parison to be instituted with the set of samples taken in 1894, and
thus to study the soil changes that have gone on during the last
twenty years. A complete botanical analysis of the grass plots is
also in hand.

It should be remembered that the object of the Rothamsted
Experiments is to study the soil and the crop, and only indirectly to
find the most paying method of manuring; hence neither the nature
nor the quantities of material applied are to be taken as indicating
the manures which should be used in practice.

ANNUAL REPORT

FOR THE YEAR 1913

spring and its dry, sunless summer. The temperature was,

on the whole, somewhat above the average excepting in July,
when it was distinctly lower. There were many more wet days in
January, March and April than usual, and at the end of the latter
month we had had no less than 10 inches of rain instead of the nor-
mal 79. June, July, August and September were, however, very
dry ; October and November had the average rain fall, but Decem-
ber was considerably drier than usual. For the whole year the
rainfall was 24°72 inches, this being 3°62 inches or 12°8 per cent.
below the average. This deficit was characteristic of much of the
Eastern part of England, although, as Dr. Mill has pointed out, there
was approximately an equal excess over much of the West. The
number of hours of bright sunshine was 1337, being 255 less than
the average. The deficit arose during the four months, January to
April, and the three months July to September, particularly during
July when we had 93 hours only instead of the average 218.

From the farmer’s standpoint the October of 1912 had been
favourable but November had been wet, so that work was delayed
and a smaller area of winter corn was sown than was intended.
December was fine, however, and the wheat and winter oats made
a good start. The land was very wet at the end of December, but
on the whole, the conditions were good till the middle of March, so
that all the spring corn went in well. Then the persistent wetness
and the increasing excess of rainfall began to tell, and work on the
potato land was brought to a standstill, and instead of getting in the
crop early in April, we had to wait to the third week in May. The
sowing of mangolds was similarly delayed and it was May 30th
before Barnfield was sown. This field, which has carried root crops
with only a three-year break since 1843, is somewhat difficult to
manage in spring: it tends to become suddenly hard on top while
underneath it is still too spongy to carry the horses. In con-
sequence, the season for getting in the seed is easily missed. Even
the dunged plots show this behaviour to some extent, though not so
markedly as those receiving no organic manure. The farm mangolds
could not be sown till June 9th and did very badly. The swedes on
Little Hoos field went in well and came up well, but a large pro-
portion of the plant died because no rain fell: more seed was sown
on July 16th but the crop failed. A fair crop of hay was secured :
it was given four clear days to make and went into the stack well,
showing no tendency to become heated like a good deal of hay in
the district that had been hurried in too quickly.

The harvest came early and the weather was exceedingly good.
Winter oats and wheat yielded well, spring oats were rather below,
but barley was above the average.

In the experiment plots, the outstanding feature of the year was
the extraordinarily large crop of barley in Hoos Field. Right from
the outset the plants grew remarkably well and they went through
to the end without a check. The plots without potash tended to
become laid: those supplied with nitrogen tended to form their ears

* te distinguishing features of 1913 were its sunless, rainy

ON

more rapidly than those which received no nitrogen: while the plots
receiving phosphates began as usual to ripen earlier than the others.
In all cases the crops were very uniform over the whole plot, and the
irregularities which showed in 1911 on plot 2A vanished entirely.
Several of the plots yielded over 60 bushels of grain, 30 cwt. of
straw and 7,000 lb. of total produce per acre: to find any parallel we
have to go back nearly 60 years. The season was of course very
favourable for barley: the spring being moist and the summer cool
and dry. But there was another circumstance which appears to have
contributed to the high yield. For 60 years in succession, barley
crops have been grown continuously in Hoos Field without any break,
but recently weeds had accumulated to such an extent that after the
harvest of 1911 it was decided to fallow the field for a year, cul-
tivating thoroughly to keep the land free from all growth during
the season, and, of course, withholding all manure. The fallow
ended in March, 1913.

There can be little doubt that the fallow played a considerable
part in bringing about the high yield. It is difficult to account
for the result on our present views as to the effects of fallowing:
something more seems to be involved than the accunaulation of
nitrate over the winter. Laboratory work, discussed later on, in-
dicates the existence of another factor: an apparent effect of a
growing crop on bacterial decompositions in the soil which is not
exerted during the fallow period. The important problems thus
opened up are under further investigation.

Another very important problem is raised by these results. The
yield—60 bushels of grain and 30 cwt. of straw—is extraordinarily
high for us, and has been obtained only three times before, v7z.,
1854, 1857 and, in Agdell Field only, in 1861. It seems to represent
the utmost our soil can do. There is remarkably little variation
between the best plots this year, seven of them varying only within
4 bushels, viz., from 60 to 64, and the variation does not become
much wider if one includes the three early years and the Rotation
experiments as well as the continuous crop. This result is readily
explained on physiological grounds: of the various plant require-
ments, all must be satisfied, or growth will not continue. If any
one is withheld, it sets a limit beyond which crop growth will not
take place. Lack of food, water, temperature may all constitute
limiting factors, any of which would prevent the crop from rising
indefinitely. The fact that our crop has not yet been pushed beyond
64 bushels during the 60 years of experiment shows that some
limiting factor is at work which is not overcome by any of the
manurial combinations or cultivation methods we use.

The limit may be set by the sheer inability of the plant to grow
any larger, in which case, the plant breeder could come to the rescue
by producing more vigorously growing varieties. But this was not
the case here. Sixty-four bushels of barley is by no means a record
crop on good barley soils, and probably many farmers have obtained
more. ‘The limit in our case seems to be set by the soil type; ours
is not a good barley soil, i.e., it is not perfectly adapted to barley,
and no mere addition of food stuffs will make it so.

The barley on the Agdell Rotation Field did not yield anything
like as heavily as on the Hoos continuous plots, the highest crop
being 33 bushels of grain, 15 cwt. of straw, and 3,500 Ib. of total

produce; these figures are far short of what has been obtained from
the same plots in certain previous years. The difference is presum-
ably the result of the fallow in Hoos Field, for all other conditions
were the same in both cases: this view is strengthened by the fact
that the unmanured plot on Agdell (which had virtually been fallowed
during the preceding year, the turnip crop having failed) gave 18°5
bushels of grain and 8 cwt. of straw, nearly the same yield as the
unmanured Hoos Field plot, 21 bushels of grain and 10 cwt. of
straw. Only where the turnip crop had grown in 1912 were the
yields markedly less than on Hoos Field.

An interesting result was obtained on the two unmanured plots
in Agdell Field. On one of these the rotation is dead fallow, wheat,
swedes, barley; on the other it is clover, wheat, swedes, barley. On
the manured plots the clover brings about an increase in the wheat,
but on the unmanured plot it usually exerts a depressing effect,
both on the wheat and the barley. This year, however, the result
was different; an increased crop was obtained on the unmanured
barley plot as well as on the manured plots as a result of growing
clover. The method of getting in the clover is to sow it broadcast
among the barley as soon as the barley is up: in some way, the
barley this year has benefited from the clover sown along with it.

The wheat on the Broadbalk plots gave much better yields than
last year in consequence of there being less Alopecurus agrestis. The
plots are still far from being clean, however, and only the yields of the
lower cleaner half of the field are given in the Table. The variety
grown is the Square Head's Master, which is well adapted to our
conditions. At a width of 7% inches apart 33 rows were sown per
plot :* during the period 1906--1912 the rows had been set 12 inches
apart to facilitate hand hoeing: there were then 19 to 20 rows per
plot in alternate years. As in the case of the barley, nitrogenous
manures were found to hasten the formation of ear, plots receiving
such manures being distinctly earlier than the rest in heading out.
None of the yields were large: 28 bushels was the highest: this was
only secured on the most heavily manured plot. These yields are below
the average on Broadbalk. On the surrounding fields 36 bushels
were obtained, but even this is not exceptionally high: we have twice
on Broadbalk—in 1863 and 1864—had as much as 50 bushels; in-
deed, in 1863 we got 56 bushels of grain and 10,000 1b. total
produce. On the Agdell Rotation Fields, however, the crops have
never been as large. These results are wholly exceptional, and
represent the combined effect of high manuring, good cultivation and
an unusually good season. In normal years our most intense scheme
of manuring yields only 40 to 45 bushels. Again the soil type seems
to be the limiting factor, and the lesson may be drawn that the best
cultivation and manuring is ineffective to push yields up beyond a
certain limit set by the season and the soil type. One might try to
push this limit higher and this is being done, but a no less useful line
of experiment is to try and secure these same yields at lower cost.

*One afterwards had to be hoed up, leaving 32 per plot.

THE LABORATORY AND POT CULTURE HOUSE.

The fundamental problem before the Rothamsted workers is
to study the mutual relationships of the soil and the plant. For
convenience of working the problem is divided into two parts: the
investigation of the factors that make for greater and more vigorous
growth on the part of the plant, and the study of the factors that
bring about changes in the plant, particularly those associated with
“quality.”

At least six soil factors are now known to be concerned
in plant growth: a proper supply of plant food; of water; of air
for the roots; sufficient temperature; adequate root room; and the
absence of harmful and injurious factors. In order to limit the
problem, the work is at present confined to one of these, which,
however, is often the most important in British agriculture; the
supply of nitrogenous plant food. Our researches are directed to the
elucidation of the chemical reactions involved in the production of
nitrates in the soil, the agents bringing about the changes, and the
influence on the whole process of soil and plant conditions.

It has long been known that the complex nitrogen compounds
contained in farmyard manure, crop residues, etc., speedily change
to nitrates in the soil. The intermediate steps are unknown, but
a beginning has been made this year by Mr. Horton who is investi-
gating the nature of the organic substances present in the soil.
The work is necessarily slow and difficult, but until it is done a satis-
factory solution of the problem will not be possible.

The complete system of crop and soil sampling adopted at
Rothamsted enables us to make up balance sheets showing what
becomes of the transformed nitrogen compounds. These prove that
the nitrification process is not complete; a portion of the added
nitrogen compound does not appear as nitrate, and some of it indeed
cannot be traced at all. The last balance sheet was made up in
1894; but the plots are now being re-surveyed so as to bring it up
to date and to show the relative efficiency of the various manurial
schemes in use at Rothamsted. It is already evident, however,
that certain methods and especially those involving the use of much
farmyard manure, are wasteful of nitrogen, and on some of the plots
less than 50 per cent. of the added nitrogen is recovered in the crop;
but it is not known how the waste occurs or whether it is an inevit-
able accompanyment of high farming.

The assumption has been made that in these cases an evolution
of gaseous nitrogen takes place, and this is of considerable scientific
interest because no biochemical process is known that would liberate
gaseous nitrogen under the conditions. But the economic interest
is much greater. Nitrogenous manures are by far the most expen-
sive, while stable or yard manure constantly tends to become dearer
to make and harder to buy. In modern agricultural conditions it is
essential to reduce waste and to get the greatest possible return
from the manures applied—indeed, the unsuccessful farmer often
differs from the successful man only in allowing to go unchecked
a series of wastages, each in itself small. A careful study has
therefore been begun to trace the missing nitrogen, to find out how
it gets lost and whether there is any means of saving it. Mr.
Appleyard is conducting experiments to see if gaseous nitrogen is

given off from the soil, but has failed to find any considerable
evolution, and it soon became clear that the reaction, if it takes
place at all, goes on too slowly to be studied in a limited time in the
laboratory.

The way round a difficulty of this sort is to seek out and study
carefully an exaggerated case as nearly as possible parallel to the
one in hand, and we had an obvious instance in a manure heap,
where marked losses of nitrogen take place from its compounds.
A manure heap, however, is an extraordinarily complex problem to
attack and required far more time than we could give it. Fortunately,
the Hon. Rupert Guinness came forward and enabled us to secure the
services of Mr. E. H. Richards, formerly of the Sewage Commission,
who now devotes himself entirely to this question. We are now, there-
fore, steadily developing our attack: while Messrs. Horton and
Appleyard are studying the chemical processes in the soil, Mr.
Richards is investigating the much more intense processes in the
manure heap. Apart from the valuable light this last investigation
may be expected to throw on the soil work, it is of great intrinsic
importance by reason of its general bearing on the nitrogen losses
from the farm.

The agents bringing about the production of nitrate, the loss of
nitrogen, and apparently other reactions in the soil, are bacteria,
and these are being studied in the James Mason Laboratory by Dr.
Hutchinson and Mr. MacLennan. Hitherto they have been dealt
with in groups only, but it has now become necessary to make
a closer study of the various types, and about a hundred have
accordingly been isolated and grown in pure culture.

The stock of soil bacteria appears to be remarkably varied; Mr.
Buddin finds some which can develope in presence of strong
organic poisons, such as phenol, cresol, hydroquinone, etc., and,
indeed, apparently feed on these substances.

The conditions under which soil bacteria work have for some
years been under investigation here, and in last year’s Report
reference was made to experiments showing that the bacteria are
not the only active organisms in the soil, but that other and larger
organisms are present which are inimical to them and keep their
numbers down. Provisionally these organisms were identified with
soil protozoa, and a survey of the soil fauna was begun to ascertain
if protozoa were present in our soil, and, if so, whether they acted
detrimentally to bacteria. Various forms were isolated from hay
infusions inoculated with soil, but there was nothing to show
whether they accurred in the soil in active forms or as cysts.
Fortunately, Mr. Martin devised a method by which some of the
protozoa can be extracted from the soil in the form in which they
actually exist, and he and Mr. Lewin have shown that numbers of
amoebae and of flagellates are in the active form and some at least
feed on bacteria in the soil. The amoebae are at present under
investigation, and prove to be new forms of considerable interest.

When soil is treated with mild antiseptics, gentle heat, or in
other ways inimical to life, it is found that the soil bacteria, after
a preliminary depression finally multiply more rapidly than before,
and the harmful factor is put out of action. Dr. Hutchinson and
Mr. MacLennan have shown that quicklime behaves like other
antiseptics and causes first a depression and then a great increase

10

in bacterial numbers, but a permanent depression in soil protozoa.
The rate of ammonia production also shows the usual increase.
Thus quicklime owes part of its effect to its sterilising action. This
discovery throws important light on the behaviour of lime in soil
and clears up much that has long been obscure. Other effects of
lime on the soil of a chemical and physical nature were observed
and investigated.

The usual demonstrations have been continued showing the
improvement in productiveness brought about by partial sterilisation.
Several large scale trials have been made in commercial glasshouses.
The new Experiment Station in Lea Valley, now in course of
formation, will in future take over much of this demonstration
work. The laboratory work has been continued in conjunction with
Mr. Buddin, who has been investigating the effect of certain typical
organic antiseptics with a view to devising some general schemes
of classification of substances suitable for practical application.

An investigation by Dr. Hutchinson and Mr. Goodey of the
samples of soil collected from our plots at various periods and stored
in dry condition has further illustrated the close parallelism estab-
lished in earlier papers between the soil protozoa and the factor
detrimental to bacteria. Samples collected and bottled in 1874
behaved normally on moistening—the bacteria developed, but not to
any very great extent—amoebae and flagellates were found; on
partial sterilisation the protozoa were killed and the bacterial
numbers rose in the usual way. Samples of soil collected and
bottled in 1846 and dried in 1880, however, behaved like soil
already partially sterilised: on moistening,,.the bacterial numbers
rose considerably, no protozoa were found, and no further change
was produced by partial sterilisation. Thus long storage in dry
condition causes the soil to lose the factor detrimental to bacteria,
and it also loses its protozoa.

Besides the detrimental organisms already referred to, another
factor influencing the soil decompositions has been revealed this
year. Determinations of the nitrate content of our arable soils have
shown that there is always less accumulation of nitrate on our
cropped than on our fallow plots, even after allowing for the nitrate
taken up by the plant. Examination of the data obtained here and
elsewhere indicates that the growing crop in some way interferes
with the process of ammonia and nitrate formation. It does not
appear that the effect is merely accidental and due to some climatic
factor, for Lyttleton Lyon has already obtained a similar result at
Ithaca. Field experiments alone are not sufficient to solve the
problem; a proper series of pot experiments is required. There are,
however, several important consequences of such an interaction
between the growing plant and the soil bacteria, should it be proved
to exist. If the growing crop interferes with the process of ammonia
and nitrate formation it is obvious that one crop may be expected
adversely to affect another. Mr. Pickering’s grass growing experi-
ments afford evidence that such an interference does take place:
there is, moreover, a strong opinion to this effect among practical
men and the American Bureau of Soils has accepted it, and put for-
ward a hypothesis in explanation, one, however, which we were
unable to confirm at Rothamsted.

Dr. Hutchinson’s experiments suggest that the Pickering effect is

11

only produced in presence of soil bacteria, thus affording further
evidence of an interaction between the growing plant and the de-
composition processes. Experiments on the effect of weeds on
crops and of cross cropping were started last year in conjunction
with Dr. Brenchley to enable the facts to be determined more com-
pletely, and these are still going on.

A further consequence of such an interference between the
plant and the soil bacteria is interesting in the study of plant nutri-
tion. It has been commonly supposed that the plant must in natural
conditions get most or all of its nitrogen as nitrate because the acti-
vities of the nitrifying organisms leave it no option, and the argu-
ment was justified so long as it could be supposed that nitrification
went on independently of the growing plant. But if it turns out
that the plant interferes with the production of nitrate and ammonia
in soil then the necessity for the supposition disappears and it may
equally be possible for the nitrogen to be taken in other forms.

A beginning has also been made this year with a systematic
investigation of the soil as a medium for biological activity. This
has involved a study of the constitution of the soil, and already three
distinct lines of work are bringing out the biological importance of
the soil colloids. Mr. Prescott has been engaged in working out the
effect of dilute acids on the soil, and Mr. B. A. Keen has been
determining the rate of evaporation of water from the soil, while Mr.
Appleyard has been studying the gases absorbed by the soil and
given up only in a vacuum. The experiments are not sufficiently
advanced to justify discussion in this Report, but they promise to
throw light on the constitution of the soil.

The composition of the soil atmosphere at a depth of 6 inches
below the surface has been determined periodicaliy during the year
by Mr. Appleyard, and it has been shown to approximate very
closely to that of ordinary air, so that organisms growing in the sur-
face soil will find an atmosphere with practically normal oxygen
content.

The second great division of the Rothamsted work—the investi-
gation of the plant—is still in its opening stages, although marked
advances have been made during the year. Dr. Brenchley has
closed her work on the effect of inorganic poisons on plant growth
and has prepared a monograph in which her own and other experi-
ments are set out and the results discussed. The results are
definitely against the hypothesis that all such poisons act as stimuli
when applied in small quantities. Increased yields that require
further examination were, however, obtained in some instances with
boric acid and with manganese salts. Dr. Brenchley is now turning
to the effect of certain organic substances on plant growth and will
also test systematically the substances isolated from the soil by the
soil chemists.

An interesting investigation has been begun by Miss Adam into
the anatomical structure of certain of the grasses on the Park grass
plots. It has been observed that, where potash manures are with-
held, the grasses do not stand up well but tend to become “aid.”
Microscopic examination is being made to see whether this is
accompanied by any modification in the anatomical structure.

The chemical side of the work has progressed steadily. The
usual methods of analysing crops are based on old investigations

12

~

made before the advent of modern organic chemistry. Pharma-
cologists have already adopted newer methods and we are now doing
so for farm crops. During the past two years Messrs. Davis and
Daish, assisted by Mr. Sawyer, have worked out a satisfactory
method, of which details are given below, for estimating cane
sugar, dextrose, laevulose, and maltose in plants. A further method
is now being elaborated for determining the amount of starch; this
is based on the fact that Taka diastase hydrolyses starch completely
to maltose and dextrose, no dextrin being formed.

The following papers have been published during the year :—

I. “The Weeds of Arable Land.” III. WINIFRED E.
BRENCHLEY. Annals of Botany, 1913. 27, 141—266.

In previous seasons the investigation had been confined to
sedentary soils; this year (1912), however, the records were taken
on the drift soils of Norfolk. The general results, however, are
closely in agreement with those obtained before, but the Norfolk
weed flora agrees more closely with that of Bedfordshire than with
that of the West Country. As before, the association between weeds
and soil is sometimes general, sometimes only local, but the follow-
ing weeds were characteristic of the soils examined this year :—

CLay & HEAvy LOAM. LOAMS.
Alopecurus myosuroides Anthemis Cotula
Geranium dissectum Bellis perennis
Heracleum Sphondylium Brassica alba
Linaria Elatine Chrysanthemum leucanthemum
Potentilla reptans Euphorbia Peplus
Ranunculus arvensis Lolium perenne
Stachys palustris Lychnis dioica

Papaver Argemone

SAND & SANDY LOAMS. SANDS.
Chrysanthemum segetum Bromus mollis
Rumex Acetosella Echium vulgare
Scleranthus annuus Erophila verna
Spergula arvensis Lycopsis arvensis

Myosotis collina
CHALK.
Artemisia vulgaris Euphorbia Helioscopia
Cichorium Intybus Linaria vulgaris

Crepis virens
A relationship was found between the weed flora and the crop
dependent on the purity of the crop seed, the habit of growth of the
crop, and the character of the cultivation given.

Il. “A Study of the Methods of Estimation of Carbohydrates,
especially in Plant Extracts.’ \W.A. Davis & A. J.
DAISH. Journal of Agricultural Science, 1913. 45,
437—468.

A careful study has been made of the various methods by which
the sugars can be determined in crops and those most suitable have
been embodied in a scheme which has been found to work satisfac-
torily.

13

The plant material is extracted in a large metal Soxhlet ex-
tractor for 18 hours. The extract is then evaporated 12 vacuo
(700 to 740 mm.) to a small volume and made up to a definite volume,
e.g. 500 c.c. Of this 2 portions of 20 c.c. each are evaporated to dry-
ness and dried im vacuo for 18 hours at 100°C. This gives the
total dry matter in the extract. 440 c.c. are treated with the requisite
volume of basic lead acetate solution, filtered under pressure on a
Buchner funnel, washed and made up to a known volume, 2 litres.
This is called Solution A.

300 c.c. of solution A are deleaded by means of solid Naz COs
and made up to 500 c.c. This is called Solution B.

(1) 25 c.c. of B are used for direct reduction and polarised ; *
the reduction is due to dextrose, laevulose, maltose, pentoses.

(2) FoR CANE SUGAR. Invert 50 c.c. of B:

(a) By invertase. Make neutral to methyl orange by a
few drops of concentrated sulphuric acid, and add 1—2 c.c. auto-
lysed yeast and two or three drops of toluene and leave 24
hours at 38—40°C. After this period, add 5 to 10 c.c. alumina
cream, filter and wash to 100 c.c. Take the reducing power
of 50 c.c. (=25 c.c. B) and polarise.

(b) By 10 per cent. citric acid. Make faintly acid to methyl
orange by a few drops of concentrated sulphuric acid and add
a weighed quantity of citric acid crystals so as to have 10 per
cent. of the crystalline acid (CsHs0,+H2O) present. Boil
10 minutes, cool, neutralise (to phenolphthalein) with sodium
hydroxide, make to 100 c.c. and determine reducing power of
50 c.c. (=25 c.c. B); polarise.

CANE SUGAR is calculated from the increase of reducing
power or change of rotation caused by inversion. The values
obtained by the two methods a and b should agree closely.

(3) For MatToseE. Another 300 c.c. of Solution A is deleaded
by means of hydrogen sulphide and filtered, the precipitated sulphide
being washed until the total volume of filtrate and washings is about
450 c.c. Air is then sucked through this for about 14 hours to expel
hydrogen sulphide, a very little ferric hydroxide is added to remove
the last traces of the latter, and the solution is made to 500 c.c. It
is filtered and

50 c.c. fermented (a) with S. marxianus
A & (b) ,, S. anomalus
_ (c) ., S. exiguus
and two lots dand e of 50 c.c. are fermented with baker’s yeast.
It is generally necessary in order to ensure good growth of the yeast
to reduce the acidity by adding 2 to 5 c.c. of N-sodium carbonate to
the 50 c.c. to be fermented; 5 c.c. of sterilised yeast water is also
added, the mixture is sterilised in the usual way and inoculated in
the inoculating chamber with the pure culture of yeast. It is then
stoppered with cotton wool and the yeast allowed to incubate for 21
to 28 days at 25°.

* The polarisation of these dilute solutions is usually small and it is therefore
necessary to take the reading with a long tube (at least 200 mm. in length) with
an instrument reading accurately to ~},°, the temperature being maintained con-
stant at 20° C within 74°. It is an easy matter, using a Lowry thermo-regulator
and circulating the water by means of a small pump, to keep the temperature

constant to y4,° but differences of temperature less than ;4° hardly make a per-
ceptible difference in the readings with such dilute solutions as these.

14

After completion of fermentation 5 c.c. alumina cream is added,
the solution made to 100 c.c. at 15°, filtered, and 50 c.c. used for re-
duction. The difference between the average reduction with a, b,
c and the average of d and e gives the reduction due to maltose.

(4) PENTOSES. These are approximately determined in 50
c.c. of A, by distilling with hydrochloric acid according to the
A.O.A.C. method weighing as phloroglucide.

(5) When the reduction due to pentose and maltose has been
allowed for in 1, the remaining direct reduction is due to dextrose
and laevulose; the actual proportions of these two sugars are cal-
culated from the reducing power combined with the corrected rotation
as suggested by Brown and Morris in the 1893 paper.

Ill. “A Simple Laboratory Apparatus for the Continuous
Evaporation of Large Volumes of Liquid in Vacuo.”
W. A. Davis. Journal of Agricultural Science, 1913.
5, 434—436.

A description of a simple apparatus used in the above analytical
process.

IV. “The Soil Solution and the Mineral Constituents of the
Soil.” A. D. HALL, WINIFRED -E. BRENCHLEY and
LILIAN M. UNDERWOOD. Philosophical Transactions
of the Royal Society, 1913. 204, 179—200.

Solutions were made by extracting the soils from certain of the
Rothamsted plots on which wheat and barley had been grown for
60 years and upwards. Wheat and barley were grown in these
solutions, which were renewed fortnightly. The comparative growth
in the solutions was closely parallel to the growth of the crop on the
plots in the field and corresponded to the composition of the solutions.
The composition of the solutions as regards phosphoric acid and
potash corresponded to the past manurial treatment of the soils and
to the amount of phosphoric acid and potash they now show on
analysis. Growth in the soil solutions agreed with the growth in
artificial culture solutions containing equivalent amounts of phos-
phoric acid and potash. Growth in the soil solutions from imperfectly
manured plots was brought up to the level of that in the solutions
from completely manured plots on making up their deficiencies in
phosphoric acid and potash by the addition of suitable salts. The
phosphoric acid and potash content of the soil solutions was of the
same order as the phosphoric acid and potash content of the natural
drainage water from the same plots.

Wheat grew as well as barley in the solutions of the wheat soils
and vice versa. In similar sets of solutions from the same soils
the growth of buckwheat, white lupins and sunflowers corresponded
with that of wheat and barley. Boiling effected no alteration in the
nutritive value of the soil solutions.

In nutritive solutions of various degrees of dilution the growth of
plants varied directly, but not proportionally, with the concentration
of the solution, though the total plant food present in the solution
was in excess of the requirements of the plant. When the nutrient
solution was diffused as a film over sand or soil particles, as in
nature, there was no retardation of growth due to the slowness of

15

the diffusion of the nutrients to the points in the liquid film which
had been exhausted by contact with the roots. Growth in such
nutrient solutions forming a film*over sand particles was much
superior to the growth in a water culture of equal concentration,
but the growth in the water culture was similarly increased if a
continuous current of air was kept passing through it.

From these data it is concluded :—

(1) The composition of the natural soil solution as regards
phosphoric acid and potash is not constant, but varies significantly
in accord with the composition of the soil and its past history.

(2) Within wide limits the rate of growth of a plant varies with
the concentration of the nutritive solution, irrespective of the total
amount of plant food available.

(3) When other conditions, such as the supply of nitrogen,
water, and air are equal, the growth of the crop will be determined
by the concentration of the soil solution in phosphoric acid and
potash, which, in its turn, is determined by the amount of these
substances in the soil, their state of combination, and the fertiliser
supplied.

(4) On normal cultivated soils the growth of crops like wheat
and barley, even when repeated for 60 years in succession, does not
leave behind in the soil specific toxic substances which have an
injurious effect upon the growth of the same or other plants in the
soil.

The net result of these investigations is to restore the earlier
theory of the direct nutrition of the plant by fertilisers. The com-
position of the soil solution which determines the growth of the plant
is dependent upon the amount and the mode of combination of the
phosphoric acid and potash in the soil, both of which are affected by
the fertiliser supply, though to what extent is not yet determinable.

V. “The Effect of Partial Sterilisation of Soil on the Pro-
duction of Plant Food. Part II. The Limitation of
Bacteria Numbersin Normal Soils and Its Consequence.”
E. J. RUSSELL and H. B. HUTCHINSON. Journal of
Agricultural Science, 1913. 5, 152—221.

The conclusions reached in the previous paper have been con-
firmed and extended. Fresh evidence is adduced that bacteria are
not the only inhabitants of the soil, but that another group of
organisms occurs, detrimental to bacteria, multiplying more slowly
under soil conditions and possessing lower power of resistance to
heat and to antiseptics.

In consequence of the presence of these detrimental organisms,
the number of bacteria present in the soil at any time is not a
simple function of the temperature, moisture content and other con-
ditions of the soil. It may, indeed, show no sort of connection with
them; thus rise of temperature is found to be ineffective in increas-
ing the bacteria in the soil; increase in moisture content has also
proved to be without action. The number of bacteria depends on
the difference in activity of the bacteria and the detrimental
organisms.

But when soil has been partially sterilised the detrimental
organisms are killed and the bacteria alone are left. It is then
found that increase in temperature (up to a certain point) favours

16

bacterial multiplication and causes the numbers to rise. Variations
in moisture content also produce the normal results on partially
sterilised, but not on untreated, soils.

The detrimental organisms are killed by any antiseptic vapour,
or by heating the soil for three hours to 55°-60°C:: they suffer con-
siderably when the soil is maintained at lower temperatures (40°C)
for a sufficient length of time. Cooling to low temperatures also
depresses them, although it fails to kill them.

The completeness of the process can be accurately gauged by
the extent to which the bacteria suffer. Whenever the treatment is
sufficiently drastic to kill the nitrifying organisms and to reduce
considerably the numbers of the other bacteria (as shown by the
counts on gelatine plates) it also kills the detrimental organisms.
If the soil conditions are now made normal, and the antiseptic is
completely removed, rapid increase is observed in the bacterial
numbers and the rate of production of ammonia. A temporary or
partial suppression of the factor is, however, possible without
extermination of the nitrifying organisms.

Once the detrimental organisms are killed, the only way of
introducing them again is to add some of the untreated soil. But
the extent of the transmission is apt to be erratic, being sometimes
more and sometimes less complete than at others; occasionally the
infection fails altogether. We have not yet learned the precise
conditions governing the transmission. ;

Provisionally we identify the detrimental organisms with the
active protozoa of the soil, but as the zoological survey is yet
incomplete we do not commit ourselves to any particular organism
or set of organisms, or to any rigid and exclusive definition of the
term protozoa.

The increase in bacterial numbers following after partial steri-
lisation by volatile antiseptics is accompanied by an increase in the
rate of ammonia production until a certain amount of ammonia or
of ammonia and nitrate has been accumulated, when the rate falls.
Thus two cases arise: (1) when only small amounts of ammonia
and nitrate are present there is a relationship between bacterial
numbers and the rate of ammonia production; (2) when large
amounts of ammonia or of ammonia and nitrate are present there
is no relationship. The limit varies with the composition and con-
dition of the soil.

Complications are introduced when the soil has been partially
sterilised by heat, because heat effects an obvious decomposition of
the organic matter, thus changing the soil as a medium for the
growth of micro-organisms. The bacterial flora is also very con-
siderably simplified through the extermination of some of the varie-
ties. These effects become more and more pronounced as the
temperature increases, and their tendency is to reduce the numbers
of bacteria. We find maximum bacterial numbers in soils that
have been heated to the minimum temperature necessary to kill the
detrimental organisms (about 60°C). Both bacterial numbers and the
rate of decomposition in such soils approximate to those obtaining
in soils treated with volatile antiseptics, and the above-mentioned
relationships between these quantities also hold.

Although bacterial numbers are at a minimum in soils heated
to 100°, the decomposition effected is at a maximum.

AA

With this exception, it is generally true that bacterial multipli-
cation may go on without increasing the rate of production of
ammonia, but an increase in the rate of production of ammonia does
not take place without bacterial multiplication.

The increase in bacterial numbers brought about by addition of
bacteria from the untreated soil into partially sterilised soil leads to
still further production of ammonia and nitrate, unless too large
a quantity of these substances is already present. But the sub-
sequent depression in bacterial numbers consequent on the develop-
ment of the detrimental organisms is generally (though not always)
without effect on the rate of decomposition, apparently because it
does not set in until too late.

VI. “The Partial Sterilisation of the Soil by means of
Caustic Lime.” H. B. HUTCHINSON. Journal of
Agricultural Science, 1913. 5, 320—330.

When a soil is treated with lime, either in the caustic or mild
form, an improvement of its physical condition results; the treatment
gives rise to a certain amount of chemical action with a liberation of
nutrient substances, and also, by neutralising any acids present,
provides a more favourable environment for the various classes of
organisms existing in the soil.

This in itself is not sufficient to account for many of the results
that are obtained in practice. Caustic lime has a recognised value
as an antiseptic and, when applied to the soil, even in the presence
of large quantities of calcium carbonate, has a pronounced effect in
disturbing or even destroying the state of equilibrium, normally
existing between the micro-flora and the micro-fauna of the soil.

The action of caustic lime has been found to be intermediate in
character between that exercised by volatile antiseptics and the
changes induced by high temperatures. In addition to killing many
bacteria and causing the death of the larger protozoa, which would
appear to exert a depressive action on the growth of bacteria, it
brings about a decomposition of the organic nitrogenous constituents
of the soil. It is highly probable that these decomposition products
serve as nutrients for bacteria and are subsequently resolved into
plant food.

The depression of bacterial activities in soils treated with
caustic lime would appear to persist until all the oxide has been con-
verted into carbonate; this is followed by a period of active bacterial
growth and increased production of plant food. The inhibitory
action of caustic lime on soil bacteria varies with the soil and is

‘ possibly governed by the organic*matter present.

In the main, pot experiments give results similiar to those ob-
tained in the Laboratory by bacteriological and chemical analyses.

VII. “The Action of Antiseptics in increasing the Growth
of Crops in Soil. E. J. RUSSELL and WALTER
BUDDIN. Journal of the Society of Chemical Industry,
POLS. oe.

Chemical substances are now being put upon the market for
partial sterilisation of soils, and this paper is intended to afford
guidance to the works chemist, who is called upon to supervise the
preparation of such materials. Antiseptics may be used in practice
in the following cases :—

18

(1) Where the crop yield is limited to the supply of nitrogenous
plant food, and where therefore an increased production of ammonia
in the soil is desirable.

(2) Where disease organisms and other detrimental forms are
present, and the micro-organic population of the soil has lost much
of its effectiveness in producing ammonia from the nitrogen com-
pounds of the soil. Such soils are known as “sick” soils and are
fairly prevalent in certain types of high farming and market
gardening. ‘To some extent also sewage sick soils come into this
category.

The first case is the simplest in principle, but the most difficult
in practice, from the circumstance that it is already provided for by
the various nitrogenous manures on the market. Until the antisep-
tic treatment can be made to cost less than a dressing of a nitro-
genous manure, it will have no chance against these competitors.

The second case is more difficult in principle but easier in
practice because it is not provided for, and there is a clear field here
for the application of antiseptics in practice.

The following is found to be roughly the order of effectiveness
of a number of typical antiseptics :—

Class 1. Most effective. Formaldehyde, pyridine.

Class 2. Cresol, phenol, calcium sulphide, carbon disulphide,

toluene, benzene, petrol.

Class 3. Least effective. Higher homologues of benzene
(e.g., heavy solvent naphtha), napthalene and certain of its
derivatives.

None of these antiseptics is as good as steam, either in increas- ~
ing the amount of ammonia in the soil, in killing insect and fungoid
pests, or in inducing a good fibrous root development. In all trials,
therefore, a steamed soil is included to set the standard of excellence
previously unattained by antiseptics.

The following experimental methods have proved useful in our
laboratories and may be adopted by the works chemist in sorting out
possible antiseptics for practical purposes :—Some rejected glass-
house “‘sick’’ soil—the worse its character the better for the experi-
ment—is divided into three lots, one is left untreated while the
other two are treated respectively with 0°1 and 0°25 per cent. of the
antiseptic, care being taken that the admixture is as far as possible
perfect. Five experiments are then carried out :—

(1) Chemical analyses are made at periodical intervals extend-
ing over a month, to ascertain the rate at which ammonia and nitrates
accumulate in the treated and untreated soils.

(2) At the same time, bacteriological counts are made by the
gelatine plate method to ascertain the rate of development of
bacteria.

(3) Some of each lot is inoculated into test tubes containing a
one per cent. hay infusion, and after six days’ incubation at 25°C.
drops of the infusions are examined under the low power of the
microscope for protozoa. If these organisms are killed by the treat-
ment, it commonly happens that other harmful organisms are killed
also.

(4) Seeds are sown in the soils and the young plants are care-
fully watched to observe the development of “damping off” root,
knots, or other diseases.

19

(5) Plants are grown right through to fruiting and the produce
weighed.
VIII. “On the Growth of Plants in Partially Sterilised
Soils.” E. J. RUSSELL and F. R. PETHERBRIDGE.
Journal of Agricultural Science, 1913. 5, 248-287.

Seven important directions have been found in which partially
sterilised soils differ from untreated soils as media for plant growth.

(1) There is generally a retardation in germination but some-
times partial acceleration (i.e., affecting some of the seeds only).

(2) There is generally an acceleration in growth up to the time
of the appearance of the third or fourth leaves, but sometimes
a marked retardation, especially in rich soils heated to 100°C. We
have failed to discover the conditions regulating the retardation, and
can never predict with certainty whether or not it will set in. On
the whole we have observed it more frequently during dull winter
days than in the brighter spring or summer days.

(3) When this retardation occurs it is accompanied by a very
dark green leaf colour and either the formation of a purple pigment
or a tendency for the leaves to curl towards the under side. The
whole appearance is strongly suggestive of an attempt on the part
of the plant to reduce assimilation.

(4) Later on the purple colour goes and the curling ceases;
rapid plant growth then takes place. The subsequent growth is
finally proportional to the amount of food present.

(5) Plants grown in soils heated to 100° show a very remark-
able development of fibrous root unlike anything obtained on un-
treated soils.

(6) Plants grown on soils heated to 100° have, in comparison
with those on untreated soils, larger leaves of deeper green colour,
stouter stems, usually shorter internodes; they flower earlier and
more abundantly, and contain a higher percentage of nitrogen and
sometimes of phosphoric acid in their dry matter; the roots and
stems give up their nitrogen, phosphorus, and potassium more com-
pletely to the fruit.

(7) Plants grown on soils heated to 55° or treated with volatile
antiseptics show fewer of these effects; there is only rarely a re-
tardation in seedling growth but usually an acceleration, sometimes
a rapid one, succeeded by a period of steady growth which is finally
proportional to the amount of plant food present. No specially
marked development of fibrous root or shortening of the internodes
occurs, but there is an increase in the percentage of nitrogen and
sometimes of phosphoric acid in the dry matter as compared with
plants raised on untreated soils, and also a more complete trans-
location of these materials to the fruit.

IX. The Effect of Bastard Trenching on the Soil and on
Plant Growth. E.J. RUSSELL and S. U. PICKERING.
Journal of Agricultural Science, 1913. 5, 483—496.

Bastard Trenching as originally performed, consists of two
distinct operations; loosening the lower spit of soil and digging into
it farmyard manure or other fertilising material.

The experiments described in this paper were made on plots that
had been bastard trenched to a depth of three spits, but not manured.
The first and second spits were put back in their natural order, but

20

no manure was added. The experiment, therefore, deals simply
with deep cultivation effect, and is not complicated by any disturbing
factors due to the operation of the manure.

The effect of bastard trenching on the soil, when unaccom-
panied by manuring, was found to be only smal]]. Beyond a ten-
dency to facilitate the drainage of water from the top spit to the
lower spit in the clays and heavy loams, and slightly to increase the
nitrates, no definite change seemed to be produced. ‘The effect on
the growth of trees appeared to depend largely on the character of
the seasons following the trenching and planting, as was exemplified
by the different results obtained in the same plot of ground after
trenching in 1895, and after retrenching in 1910. The practical
conclusion may be drawn that bastard trenching by itself, done
without addition of manure to the bottom spit, is not likely to bring
about any sufficient change in the soil to justify the trouble and ex-
pense of the operation. Of course, if there is a pan to be broken
the case is different; but where there is no pan, the main use of
bastard trenching seems to be that it affords an opportunity for
adding manure or other fertilising material to the bottom spit.
Unless advantage is taken of this, the real benefit of the process is
missed.

X. “The Composition of Rain Water collected in the Hebrides
and in Iceland.” N. H. J. MILLER. Journal of the
Scottish Meteorological Society, 1913. [iii] 16, 141—158.

Systematic analyses have been made for a number of years of
the amounts of ammonia and nitrate in rain. The question was at
one time of great interest in connection with nutrition of crops,
Liebig having maintained that plants derived a considerable pro-
portion of their nitrogen from this source. The analyses have long
disproved this view and interest has now shifted to another problem :
the source of the ammonia invariably found in the rain water. Sam-
ples of rain have been collected systematically from various stations
in the Hebrides and in Iceland, remote from atmospheric pollution,
in order to ascertain how the amounts of ammonia and nitrate com-
pare with those found at Rothamsted. The results were as follows :—

NITROGEN
ec Ran Per Acre, per
> / ®
Per Million Annum (ia
| RAINBAD 1 Fas TS
As As As As :
Ammonia Nitrates Ammonia _ Nitrates | ToTaL
ar Inches Average |_ Average | are,
_ Rothamsted Lon 28°04 0°437 0°202 2°774 1°251 4°025
| Laudale, Ardgour 88°80 0°138 0°063 2°784 1260 4°044
Barrahead,
Berneray TH 35'28 0°145 0°138 1°164 1°104 2°268
Shillay Monach
Islands, N. Uist. 48°36 0°115 0°054 1°260 0°588 ) 1°848
Butt of Lewis,
Stornaway ... 41°19 0°039 0°033 0°361 0°305 | 0°666
Vifilsstadir,

Ieelandticay “s.4 38°34 0'091 | 0°030 0°802 0°263 | 1065 |

21

All these samples contain ammonia and nitrate, although the
amounts are low. Indeed, those from the Butt of Lewis and
Vifilsstadir are the lowest hitherto recorded, the amount of ammonia
in the Butt of Lewis rain being even less than was found in the
southern regions by the Charcot expedition.

Seeing that ammonia is always present, it is important to ascer-
tain where it comes from. The old theory of Boussingault, that
atmospheric ammonia is derived from the sea, and the more recent
one of Schloessing, that tropical seas give up ammonia to the air, are
not supported by any analyses of rain collected near the sea in tropi-
cal countries, all of which show less ammonia than is found at
Rothamsted. The only possible explanation seems to be that the soil,
or at any rate arable soil, is continually giving up some of its
ammonia to the air. So that instead of the rain contributing three
or four pounds to the acre, it seems more probable that it is merely
restoring some portion of the ammonia which the soil has previously
lost.

XI. “The Excystation of Colpoda Cucullus from its Resting
Cysts, and the Nature and Properties of the Cyst
Membranes.” T.GOODEY. Proceedings of the Royal
Society, 1913. 86 B, 427—439.

This research has shown excystation is brought about in con-
sequence of the dissolution of the cyst membrane by an enzyme, and
an attempt has been made to follow out the main steps of the process.

The cyst membranes of Colpoda cucullus consist of the outer
ectocyst and the inner endocyst, and the reactions of each have been
studied. The endocyst appears to be of carbohydrate nature, but it
differs from any other carbohydrate and appears to be new. The
name ‘Cystose”’ is suggested for it. During excystation the endocyst
is set free by the rupture of the etocyst, and the Colpoda liberates
itself by the rapid digestion of the endocyst by means of an enzyme
which it secretes. This enzyme differs from diastase and other
known enzymes, and is named Cystase. Full details are given in the
paper of the tests adopted and the results obtained.

XII. “Soil Protozoa.” K.R. LEwIn and C. H. MARTIN.
Nature, 1914. 92, 632 (Feb. 5, 1914).

A method of obtaining permanent preparations of protozoa in
the state in which they are living in the soil.

The fixative hitherto used in our experiments has been picric
acid in saturated aqueous solution, but we have since found this re-
agent to be less serviceable in the case of clay soils than the
following mixture :—Saturated aqueous solution of mercuric chloride,
1 pt.; methylated spirit, 1 pt. The soil should be crumbled into
this fluid, and mixing is best accomplished by gently shaking the
containing vessel, care being taken to avoid making the clay com-
ponent of the soil pass into suspension.

A delicate film containing protozoa appears on the surface
of the liquid, and this can be removed by floating cover-slips over it,
and stained by the usual methods.

22

OTHER PUBLICATIONS.

The following other publications have been issued during the
year :—

“Guide to the Experimental Plots. Rothamsted Experimental
Station.” 2nd Edition, 1913. John Murray, 1/- net.

“Yellow Rattle as a Weed on Arable Land.’ WINIFRED E.
BRENCHLEY. Journal of the Board of Agriculture, 1913.
19, 1005—1009.

“The Complexity of the Micro-organic Population of the Soil.”
BE, J, RUSSELL. Science, 1913: 37, 519—522,
[A reply to certain American criticisms of the work of Russell
and Hutchinson. |

“Chrysanthemum Growing in Partially Sterilised Soils.” E. J.
RUSSELL. Transactions of the National Chrysanthemum
Society, 1913.

[An account written for nurserymen of experiments showing the
effect of partial sterilisation on the growth of chrysanthemums, and
in particular that the partial sterilisation of old chrysanthemum
compost renders it again suitable for use. |

“The Fertility of the Soil.’ E. J. RUSSELL. Cambridge
Manuals of Science and Literature. 1/- net.
[A general account of the present position of soil fertility
problems. ]

MONOGRAPHS.

It is proposed to bring out a series of monographs in which the
members of the Staff will discuss the particular problems they have
been investigating, as soon as sufficient material has accumulated to
render such a course desirable. Two have already been written :—

“Soil Conditions and Plant Growth.” E.J. RUSSELL. Long-
mans & Co., 5/- net.

“Inorganic Plant Poisons.” WINIFRED E. BRENCHLEY.
Cambridge University Press. (Ready shortly.)

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‘CI6I “ONILSHAUVH AUNV ONIMOS AO SALVG

CROP YIELDS
ON THE EXPERIMENTAL PLOTS.

1 acre = about 0°404 Hectare.
1 bushel a he = 0°364 Hectolitre.
1 lb. (pound avoir.) oe = ae 0°453 Kilogramme. )
1 cwt. (hundredweight) ... = » 50°8 Kilogrammes.
1 bushel per acre ... = ; 09 Hectolitre per Hectare.
1 lb. per acre ee 1:12 Kilogramme per Hectare. b
1 cwt. per acre = ,, 1256 Kilogrammes per Hectare. |
CROPS GROWN IN ROTATION. AGDELL FIELD.
PRODUCE PER ACRE.
O. M. G:
Complete
U i Mineral Mineral and
nes Manure. Nitrogenous
f Manure.
Year. CROP: - eh! ae )
ee Wert ¥. 4. 1: i
Beans Beans | Beans |
Fallow.| °F [Fallow or | Fallon |
Clover over. | Clover.
SIXTEENTH COURSE, 1908-11.
* on : a 7 Gite soe oi 7 - | ;
1908 Roots (Swedes) Cwt. 2156 64] 1790 235°8 | 3954 | 314°0 |
|
1909 {, Barley Grain ... Bus. 11°4 100 | 174 221] 268 | 3374 |
~ (| Barley Straw ... Cwt. 10'1 113 127 16°9 18°7 | 23°8
1910 Clover {1st crop Cwt. = 1°6 = 24°71 == 32°2 |
Hay (2nd crop Cwt. = 15°8 = 40°0 =! a
1911 {| Wheat Grain ... Bus. | 23°99 | 245] 319 | 378] 33:3 | 380 |
Wheat Straw ... Cwt. 20°4 21-4 28°6 eta tge. 29°3 32°5
/ ;
PRESENT COURSE (17th), 1912- ;
1912 Roots (Swedes) Cwt. 8°2 2.3 LOLS 251°9 | 586°6 | 463°0 )
1913 Barley Grain Bus. 18°5 24°6 24°7 33°2 22°0°| 32°5 |
Barley Straw ... Cwt. 82 13°0 10°6 14° 9°0: |}, B30

_———

METEOROLOGICAL RECORDS, 1913.

Za

(See ‘‘Guide,’”’ 1913, page 18, Table IX.)

Rain.
E ; ae or ada Temperature.
| No. of :
Total Fall. Rainy Bright
| Days Sun-
hs 3 shine.
| 5-inch | aoe i0vo =| 20 ins. | 40 ins. | 60 ins. at
| Funnel| Acre Acre | deep. deep. | deep. a
Gauge. | Gauge. | Gauge
Inches. | Inches No. |Inches. Inches. | Inches.} Hours.] °F. =f E¥e ay
Jan. 3°163 3°360 21 3°046 SREP oe | Slat: 39,4.) 4 ie Sone
Feb. C°953 1°004 116i 0°658 0°767 | 0°785 a4 465i 3a
March 2°406| 2°518 21 0°833 0°891 0°886 103°0} 50°9| 3671
April 3/043 '|| 3 163 20 1°409 azo) lose 1170 53°53 | 38°2
May 721 1°806 12 0°748 0°880 | 0836 2069] 628); 43°8
June 1°145 | 1°200 | 8 0°003 0°021 0°025 205°6] 67°1{ 481
‘| July 1°190 1 A421 Oa) i == 0°001 0°001 93°0}] 65°5; 49°99
August at L576 10 = = z= 152°8} 686; 50°7
Sept. 1°380 1°496 11 0°181 0°162 0°124 12450 |) 6557) 4956
Oct. 3°382 3°494 18 Pes 32, 2°082 2°026 106°3 | 586}; 45°2
Nov 2°863 2°944 vA 2°422 2 S42, 2°283 929 1-33°2)| SBaf
Dec 0°786 | 0°872 14 0°379 0°360 0°302 42D ADO | S5n8
| Fotal or | 53-476 | 24°724| 181 | 11°928| 12179| 11°929] 13368] 56°9| 42
Mean
i mene Se A os = = Le —
For dates of sowing, etc., see page 23.
MANGOLDS, BARN FIELD, 1913.
(See *‘Guide,”’ 1913, page 13, Table VI.)
7 | Cross Dressings.
on ees A. Bes. PRC
Strip. Strip 2
Manures. aeed . __|Rape Cake &
! : Nitrate of Ammonium! : Jae
None. Ammonium |Rape Cake.
Soda. Salts.
___ Salts.
Tons: Tons. Tons. Tons. Tons.
: (R. 18°27 29°05 22°19 22°83 21°32
ee Ee only iL. ¢71| 7°48 7°25 7°26 614
|
2 ! Dung, Super, (R. 18°88 28 36 29°28 50°25 27 96
Potash (L:. 4°53 7°93 8°23 10°22 12D
: ( 18°25 ) : 2
4 | Complete [eR ia 6) oe bic aan
ieee eels Liang See 4°53 8°84 5°24
t 7:62)
i 5 Superphosphate (R. 4°06 17°38 510 6°73 8 25
only (Ee 44 oA 4°10 5°08 AOD
6 | Super and (R. 308 14°34 10°79 19°52 16°52
) Potash {L: 1°43 5°90 5°30 8°78 4°92
Neer Cuil (R. 590]. -17°00 13:48 20°89 20-02
Saini ii Ges ee 5 | 6°33 3°59 8°12 a°34
: (R. 368 11°39 442 5°76 7°25
N J
i ang (L. 121) 5°78 3°97 4°29 415
R=roots. L=leaves. Tons per acre in all cases.

26

HAY. THE PARK GRASS PLOTS, 1913.
(See ‘‘Guide,”’ 1913, page 21, Table XI.)

| Yield of Hay per acre.
| . | A
Plot. | Manuring. / 1S ay | $7 soa
Oa An a ) Prana
| Ist Crop. |2nd Crow! Total. | ae
Rwra” P| *cwts cwt.. | cwt. | ieme
3) : tf 12°4 O16 * 1) ae 20°9
12 | Unmanured ... Rae cp | 149 0-7 156 239
2 | Unmanured; Dung 8 years, 1856-63 15'S ti) iio 15:8 | 286
5-1 | (N._ half) Unmanured ; following» |
| Amm. Salts alone, 42 yrs. 1856-97 | 20°2 0°8 21°0 14°4 (1)
| :
/ 1 | Amm. Salts alone; with Dung 8 yrs.
| 1856-63 560 eee Aeaiee AO 2s 28°8 35°9
17 | Nitrate of Soda alone. 26°6 1°9 28°5 53°F,
4-1 | Superphosphate of Lime ... a fj NL 06 21°77 21°6
8 Mineral Manure without Potash ... 20°3 10 213 28°0
7 | Complete Mineral Manure ... 40°6 2°6 43°2 40°9
| 5-2 (S. Half) Complete Mineral Manure :
| following Amm. Salts alone for |
42 yrs. 1856-97 sci Bie || 17 | 369 | aaa
6 | Complete Mineral Manure as s plot 7: |
| following Amm. Salts alone 13 a
| 1856-68 aK 366 | 38 40°4 37°2
| 15 | Complete Mineral Manure a as 5 plot 7: .
following Nitrate of Soda alone 18
yrs. 1858-75 +f deol, OES "7 33°5 | 368 ~]
| 4-2 | Superphosphate and Amm. Salts ...| 454 | 23 47°7 | 33°5 |
10 | Mineral Manure (without Potash)
| andAmm. Salts... We 2'0." ||) 46:2)
9. | Complete Mineral Manure and Amm. /
ieoaltci. 5 | 36°0 21 58°71 Sst
Lite Complete Mineral Manure and extra |
Amm. Salts.. bet OAS 7:2 | yAlee: 66°5
11-2 | As plot 11-1, and Silicate of ‘Soda BEE) Mes 2 eta MOE S| | 7670 73:3
16 | Complete ee Manure and Nit.
| Soda=43 lb. oe | 42°9 3°9 468 | 463
14 | Complete Mineral Manure and Nit. |
| Soda=861b.N. ... aoe co 51°9 3°8 55°77 aes
13. | Dung and Fish Guano, once in 4 years Ao 51 505 | —

(1) 15 years, 1898—1912.

BOTANICAL COMPOSITION, PER CENT.
First Crop, 1913.
(See ‘‘Guide,’’ 1913, page 22, Table XII.)

~ Ss 7 hs
Plot. | Manuring. | Graminez. | Leguminosae. | Other Orders
} |
eed ina | = oe ss |_
| | '
| Per cent. | Ber cent. | Percent.
3 Unmanured ; ay 59°0 8°7 32°3
4-1 | Superphosphate of Lime nr 56'9 10°7 32°4
8 | Mineral Manure without Potash 30°4 15°8 53°8
7 | Complete Mineral Manure a 69°5 15°3 15°2
6 | As 7, 1869 and since He see 54°4 26'8 18°8 ©
15 | As7,1876and since... 63°7 17'2 / 191
}

~

WHEAT. BROADBALK FIELD, 1913.
(See ‘‘Guide,’’ 1913, page 30, Table XVI.)

. Dressed Average
; Gra. for 61 years,
Straw 1852-1912.
Plot. | Manuring. per
Yield |W cd Acre. Deet Stes
Ae: Beehel: per Acre, per Acre.
Bushels, ‘Tb. cwt. ]| Bushels. cwt. |
2 | Farmyard Manure ... ee Eee 25°7 | 649 | 29°6 3202 34°34
3 | Unmanured ... aoe See 5°8 | 63:3 4°5 12°6 10°3 |
5 Complete Mineral Manure ... “ine Ot 6a05 Fis e| WIG ras, 1, a
6 | As5, and single Amm. Salts ae 14°2 | 64°7.| 1358 23°2 214
7 As 5, and double Amm. Salts zee) | 2018 O5s8 a sOre S20 1 32°9
8 | As5, and treble Amm. Salts ee 25 boon) Sect 366 41°1
9 As 5, and single Nitrate Soda Be PAG FS FM Ceo lit Sal | pee — —
| 10 Double Amm. Salts alone ... cetd | SOtoo | Ulas ieZ0EG 18°4
ll As 10, and Superphosphate... =6| 1345 63°9)) T67t 222.9 2213
| 12 | As 10, and Super and Sulph. Soda 1950)| (65°11 22:7) 22971 28°0
| 13 | As10, and Super and Sulph. Potash | 21°6! 656 | 363] 31°0 S155
; 14 As 10, and Super and Sulph. Mag. 19°5 | 654 | 257] 288 28°0
15 | Double Amm. Salts in Autumn, and
Minerals 224-1 (69'6, | 22°3 29°9 29°7
| 16 | Double Nitrate and Minerals Son Pee oe ODon ES se = =
_ 17 )| Mineralsalone, or double Amm. Salts { ‘Se GTO S92 Lae oi ee
| 18/| alone, in alternate years ... .-. (4217 |+65°7 | +311 | t29°9 +29°5
| 19 Rape Cake alone ade 19°8 | 65°2 | 24°8 | 25°4 (2) | 25°7 (2)
20 (1)| As 7, but excluding Superphosphate 11°0 | baie} L7-5 = =
| i on fb
* Produce by Minerals. + Produce by Ammonium Salts.
(1) Commenced in 1906. (2) 20 years, 1893—1912.

:
‘

NoTeE.—As in the previous season (1912), owing to the foulness of the land
on the upper half of the field. the produce here recorded was that obtained on
the lower half of the field only. (See notes on the crop at p. 7).

WHEAT AFTER FALLOW (without manure 1851 and since).

HOOS FIELD, 1913.
(See ‘‘Guide,” 1913, page 44, Table XX1I.)

Average |
1913 57 years
1856-1912
{ Yield—Bushels per Acre 83 160
a een aren | Weight per Bushell... 61°8 59°4
Straw : ey Ne cwt. per Acre .. eat 67 137

Total produce ane pes Ib: per Acre .» .. a 1284 |*. 2536

28

PERMANENT BARLEY PLOTS. HOOS FIELD, 1913.
(See ‘‘Guide,”’ 1913, page 37, Table XVIII. )

Average 60 years,
is ‘
alee 1852—1911.
Plot Manuring. 2 ee Al a
Weight |
Resear, | Stam. | Teste | Straw
ay he Bushes. Ib. | cwt. | Bushels. | cwt.
10 Unmanured ... Sy nee et Seno ro 9°8°| 12:7 |
2:0 Superphosphate only aa + | 341 | 56°99 | 13°6 | 19°7 ee
SIG, Alkali Salts only Bee awe .- | 25°4 [563 | 123 | 1572 ae
40 Complete Minerals ... a «- | -40°3: | 5755) TUon i es 112
‘1A Ammonium Salts only ... | 40°8 | 55°9 | 18°38 | 255° | ae
IZA Superphosphate and Amm. Salts... | 64°1 | 5771 | 279] 382 | 220
3A Alkali Salts he > i wen | 370} SO al Dirac seee 16'9
4A Complete Minerals ,, ,, +++ | 63°6 | 57°3 | 30°2] 41°5 25°0
|\1AA Nitrate of Soda only ... .- | 40°4 | 56°99) ZEON 178
'2 AA Superphosphate and Nitrate Soda ... | 60°7 | 58°0 | 30°7 | 43° | 26°3
‘3 AA — Alkali Salts eas 1» «se | 40°3 | 57°3:| 20°9)) SO
'4 AA | Complete Minerals 5 ys vee | 60°38 | 581 | 31521 4257 ees
1 AAS As Plot 1 AA and Silicate of Soda 50°7 |. 57:85) 20:0neaaae (1)! 19°7 (1))
IZIAAS1) 5 ys TAA PF +s ... | 60°1 | 576 | 315 | 42300 (1)
(SEAASHT G5) xa eeogee. AF fe “he | 50°71 | S77 | 258 tees (1)| 21°7 (1)
4 AAS b/s nn a | 50°5 | 58:0 | 31°6 | 43°6 (1)| 277 (1)
| |
|
'1C Rape Cake only ; .» Jee. | 50°3 | 57°9 | 23°9 | 35a.
|2C Superphosphate and Rape Cake ... | 55°6 | 57:0" | 2777 ese 23°6
13.G Alkali Salts ‘ 3 nF --. | 52°9 | 58°2)) 25°50 Soe 22°3
14 | Complete Minerals ,, 4, +. | 549 | 583 | 269] 405 age
|
wt Unmanured (after dung 20 years, :
| Rese an ee e g 1 | 17°9 | 24°8 (2)} 14°8 (2)
7—2 | Farmyard Manure ... ... — -.- | 61°7 | 57°8 | 31°9 | 4771 29°6
|
ro (1) 48 years, 18641911. (2) 40 years, 1872—1911.
NotTrE.—The whole of the above plots were fallowed in 1912.
BARLEY. HOOS FIELD, 1913.
(See “Guide, EP TAN les page 43, Pable XX. )
Manures applied | Dressed Grain. Total
Plot, to the Potatoes, = Straw | produ |
| 1876-1901. Yield | Weight per, per Acre. | per Acre.
Unmanured since. per Acre. | Bushel. |
| —— — ———__—_ —— —— — ——E |
: Previous ‘Cropping: Potatoes, 1876- 1901; Barley, 1902 and 1903 ;
Oats, 1904 ; Barley, 1905- 1911; Oats, 1912.
- Bushels. | _ Ib. cwt. | Te
Unmanured ... aS 18°4 56°6 92 2093
| 2 Unmanured 1882 to 1901, |
previously Dung only... 25°6 572 12°2 | 2854
3 Dung 1883 to 1901 ... doh 34°2 273 YE) 3930
4 Dung 1883 to 1901 ... oe 33°7 by fa 17a 3896 |
Previous Cropping: Potatoes, 1876-1901; Barley, 1902- 1903; - Oats, 1904 ;
Plots 5, 7, 9, Cow Peas (failed), 1905; Plots 6, 8, 10, Red Clover, 1905 ;
1906-1911, all Plots Red Clover ; ; Oats, 1912.
| )
5 | Ammonium Salts... ane 29°0 | 56°6 13°8 | 2405
Ba Nitrate of Soda is a 30°6 | 363 13°9 3302
| » |{Ammonium Salts and :
A | Mixed Minerals sail iid 37 20°9 4889
, {Nitrate of Soda and } rs
2 { Mixed Minerals FS i se lie 201 +768 )
9 Superphosphate ay ae 3379 56'8 15°8 | -37ae |
10 | Mixed Minerals bi rae 35°9 STZ 16°6 | 3935

29

LEP TLe HOOS FIELD, 1904-1913.

RESIDUAL VALUE OF VARIOUS MANURES.
(See ‘‘Guide,’’ 1913, pages 45—47.)

TOTAL PRODUCE—Grain aa Seaw or Roots and Leaves, per acre,
1908 and since.

p-*

Series

and Manuring. Swedes pagley lwheat pare Wheat Swedes |
Plot. s 1908. | 1909. | 1910. | 1911.] 1912.* 1913.
Tons. lb. lb. | Tons. IBushels. Tons.

Setyeumanured .... ... 4.24 | 14°0 | 3792 | 2270 | 116 | 19°4 86
2 | Dung (ordinary), 1904, '8 &’12 | 191 | 5128 | 2572 | 13:9 | 343 871
aes. f 1905, '9 & 13 | 14°5 | 5544 | 2681 | 141 | 269 83

4 ; A 1906 & 1910 15°5 | 4057 | 2406 | 12°5 | 29:2 1s:

5 * ‘ 1907 & 1911... | 17°3 | 4581 | 2358 | 15°8 | 26'8 69
B1 | Dung (cake fed), 1904, ’8 & 712 | 22°4 | 5362 | 2386 | 141 | 35°6 86
2 | Unmanured ... ae -. | 243 13862 | 2260 |\-12°0' F -21°8 78

3 | Dung (cake fed), 1905,'9 & 13 | 14:2 | 6641 | 2921 | 14:2 | 2974 66

4 a » 1906 &1910...| 16°9 | 4400 | 3502 | 144] 265 | 1:5
es =~ » 1907 & 1911... | 19:0 | 4298 | 2369 | 17-1 ST aca
C1 | Shoddy, 1904, 1908 & 1912 19°7 | 3969 | 2205 | 114 | 284 | 94
2 5, 1905, 1909 & 1913 16°3 | 4558 | 2387 | 116 | 261 | 107

3 | Unmanured oan an 15a 3850 | 2561 | 11°7 242 | ae iO

4 | Shoddy, 1906 & 1910 . 19°1 | 4466 | 3461 | 14:0 | 30°74 56
5 » 1907 & 1911 22°2 | 5448 | 2560 | 14-7 | 29°8 72
D1 | Guano, 1904, 1908 & 1912 20°9 | 3608 | 1742 | 10°5 | 28°8 5
2 - 1905, 1909 & 1913 15°3 | 6834 | 2114 | 115 | 241 | 107

3 f 1906 & 1910 15°9. | 4053 |3582°)\ 11-1) 22°5 | 74

4 Unmanured ne 17°4 | 4510 | 2739 | 11°8 Z26'9)| 616

5 Guano, 1907 & 1911 15°7_ | 4014 | 2374 ; 142 26°3 | 6'8
E1 | Rape Cake, 1904, 1908 & 1912 19-7 3750) 2180.) 107 | 27% | 82
2 % 1905, 1909 & 1913 | 15°71 | 5203 | 2242 | 11°7 | 22°3 55

3 - 1906 & 1910 14°5 | 3866 | 3486 | 11°5 }. 22:2 67

4 « 1907 & 1911 15°2 | 4661 | 2516 | 145 | 2571 i

5 | Unmanured nee 147 | F155 278e aa 7 OT eae
F1 | Unmanured.. 141 | 4814 | 3166| 87] 316 | 64
2 | Superphosphate, 1904, "8 & 12 | 169 4726 | 3223 | 10°9 | 33°4 82

3 . 1905, ’°9 & 13 | 14°6 | 4973 | 2922 | 11:°7 | 31°9 8°6
4 - 1906 & 1910... | 16°0 | 5280 | 2682 | 12°8 | 34°9 62

5 2 1907 & 1911... | 164 | 5641 3190 | 142 | 35°4 64
Gi _ Bone Meal, 1904, 1908 & 1912 167 | 4445 3345); 99 | 528 75
2 - 1905, 1909 & 1913 14°3 [:4922-) 3657 | 9°9 |, 32°7 74

3 raced z oo | 127 SP 4247; STOOL 92. 2936 a5
4 | Bone Meal, 1906 & 1910 142 | 4711 | 3263 | 10°5 | 31°8 39

5 Ee 1907 & 1911 19°9 | 5285 | 3512 | 126 | 344 | 5°8
H1 1 Basic ee 1904, 1908 & 1912 13°8 | 4182 | 3564 | 11°5 [e35°7 63
Zz | y 1905, 1909 & 1913 13°6 | 4530 | 3596 | 12:0 | 33°7 66
| * 1906 & 1910 13°6 | 4431 | 3943 | 12°5 | 2971 374
om rs 1907 & 1911 14°4 | 3860 | 3804 | 12°0 | 32°5 371

| 5 | Unmanured ee 11°4 | 4511 4005 | 10°5 | 30°71 2°2
The yields = the plots to which Hie pantie was Barna — any sen year are printed in heavier type.

* Dressed Grain only.

30

COMPARISON OF THE YIELD PER ACRE OF OATS AND BARLEY
GROWN TOGETHER, AND EACH ALONE, WITHOUT MANURE,
AFTER SWEDES.

; SAWPIT FIELD, 1912.
LITTLE KNOTT WOOD FIELD, 1913.

Dressed Grain.

e 2 S Total
Yield Ww eight raw. Produce.
Plot. Crop. Bere per Bushel.
1912. 1913. 1912. 1913. | 1912. | 1913. | 1912. 1913. |

“Riss Bushels. | Bushels. | Ib. Ib. cwt. cwt. | | Ib.
1 Oats and Barley ALT 26'2 | 4970'.|, 50°35) 26: 3a elo 4318 3046
2 Oats alone ae Li Se Oey, 33°1 | 41°2 | 2674) 1225 Sa8 ) 2200 |
3 Barleyalone ... 36°2 32°4 50°5 | 53°6-| 26°8 |, 18°4 oem 3800 |

CHALKING EXPERIMENTS.
BARLEY (Plumage Cross.)

LITTLE KNOTT WOOD FIELD, 1913.

_ Dressed Grain. |
pat ace, aay. Total |
Yield. Weight Produce. |
per Bushel. |
} Bushels. ] Ib. cwt. ie —
Wnehalked | 39° | o#5 | 2341 5994 |
Chalked....| 68°2. | -546 ||" 26°6 6760 |
|

Both plots manured with # cwt. Sulphate Ammonia and 23 cwt. Superphosphate
per acre.

SEEESSESEEEEEEEEEEESse

A GENERAL ACCOUNT of the Rothamsted Field Ex-
periments is given in The Book of the Rothamsted
Experiments, by A. D. Hall, M.A., price 10/6 (John
Murray).

A short summary is given in The Guide to the
Rothamsted Experimental Plots, 2nd Edn., 1913,

price 1/- (John Murray).

Lawes Agricultural Trust.

TRUSTEES.

Right Hon. A. J.

alrour, Ac; FBS... MP:
J..Francis Mason, Esq., M.P.

COMMITTEE OF MANAGEMENT.

eure ). 1. Thorold, Bart. LL.D.
(Chatrman).
er. Muller, LL.D., F.R-S.
(Treasurer).
Ecor. H. E. Armstrong, LL.D.,
FURS.

Prof. R. H. Biffen, M.A., F.
Dr: He E. Brows LE Dee
Proto’ joes Farmer, M.A., oe
Dr. A. B. Rendle, D.Sc., F.R.S
Dr. J. A. Voelcker, M.A., Ph.

ey

The Incorporated Society
for Extending the Rothamsted Experiments
in Agricultural Science.

MEMBERS OF COUNCIL.

His Grace the Duke of Devonshire, P.C., G.C.V.O. (Chairman).
J. F. Mason, Esq., M.P. (Vice-Chairman).

mor. H. E. Armstrong, LL.D.,
F.R.S.

Prof. k. H. Biffen, M.A., F.R.S.

Sewer, .. Brown, LL.D., F.R.S.

The Right Hon. Sir John T.
Brunner, Bart., P.C.

The Most Hon. the Marquess of
Lincolnshire, K.G., P.C.

Prof. J. B. Farmer, M.A., F.R.S.

Robert Mond, Esq.

Capt. J. A. Morison.

Dr. Hugo Miller, LL.D., F.R.S.
(Treasurer).

Sir W. S. Prideaux.

Dr. A. B. Rendle, M.A., D.Sc.,

F.R.S.

Sir J. H. Thorold, Bart.

Dr. J. A. Voelcker, M.A., Ph.D.

J. Martin White, Esq.

E. J. Russell,
Hon. Secretary.

32

Subscribers and Donors
to the Rothamsted Experimental Station,
1904 and since.

The Goldsmiths’ Company

(Endowment for Soil Investigation).

J. F. Mason, Esq., M.P. (The
“James Mason” Laboratory).

The Chilean Nitrate Committee.

The Permanent Nitrate Com-
mittee. .

The Fertiliser Manufacturers’ As-
sociation.

The Potash Syndicate.

The Sulphate of Ammonia Com-
mittee.

The Nitrogen Fertilisers Ltd.

The Clothworkers’ Company.

The North-Western Cyanamide
Company.

A. D. Acland, Esq.

The Right Hon. Lord Avebury,
Heit.

Capt. Clive Behrens.

Messrs. F. W. Berk & Company.

The Right Hon. Lord Blyth.

A. Brassey, Esq.

J. F. L. Brunner, Esq., M.P.

The Right Hon. Sir John T.
Brunner, Bart., P.C.

CUA. ;)..Butter,:- Esq:

Sir E. Hildred Carlile, M.P.

W. T. Coles, Esq.

Sir Kk. P. Cooper, Bart.

H. Shepherd Cross, Esq.

His Grace the Duke of Devonshire,
Pes Creve.

Harold W. Drewitt, Esq.

Messrs. Ellis & Everard.

Sir John Evans, K.C.B., F.R:S.

Sir Walter Gilbey, Bart.

Sir Eustace Gurney.

Sir A. Henderson, Bart.

H. Tylston Hodgson, Esq.

A. B. Holinsworth, Esq.

A. Howard, Esq:

The Right Hon. Lord Iveagh,
K. Pie

Messrs. W. B. Keen & Company.

H. H. Konig, Esq.

Sir Charles Lawes-Wittewronge,
Bart.

Col. H. Mellish.

R. Mond, Esq.

Capt. J. A. Morison.

W. Morrison, Esq.

A. Mosely, Esq.

Dr. Hugo Miller, F.R.S.

Henry S. Nunn, Esq.

E. Packard, Esq.

Marlborough R. Pryor, Esq.

G. Radford, Esq.

William Ransom, Esq.

The Right Hon. Lord Rothschild,
G.G.V.O.

B. S. Rowntree, Esq.

Frederick Seebohm, Esq.

Hugh E. Seebohm, Esq.

Edward Speyer, Esq.

B. Stanier, Esq., M.P.

G. Stephenson, Esq.

Messrs. Sutton & Sons.

Dr. J. Augustus Voelcker, M.A.

Messrs. Walter Voss & Company.

Phillip F. Walker, Esq.

The Right. Hon. Lord Walsing-
ham, F.R.S.

Sir J. Wernher, Bart.

J. Martin White, Esq.

T. Wilson, Esq.

W. R. Woolrych, Esq.

And the subscribers to the Lawes and Gilbert Centenary Fund.