M. of L. and A.
Department of Agriculture

OF THE ^i

COLLEGli OF /

THE NATURE OF

T

to

Of

imlmil Field.

With 21 illustrations.

By V. Q. ^OTMISTROy, :
Director of the Odessa Experiment Field.

Translation from russian.

ODESSA.

t'l

Printers, Lithographers & Book-binders ^^^i.Skalsky,Kolontaev8ft.St^eei'OwnHouse,18

1 9 1 3. ~

M. of L. and A.

Department of Agriculture

THE NATURE OF DROUGHT

accorflii to tie eviieiice of tlie Oilfissa Immil Fieli

With 21 i I i u st ratio n s.

By V. Q. ROTMISTROV,
Director of the Odessa Experiment Field.

Translation fronn russian.

ODESSA.

Printers, Lithographers & Bool(- binders •i^^i. I. Skalsky,Ko!ontaevsk.Street,OwnHouse,ll

19 13.

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Contents.

Preface 1

I. The stale of the drought question 3

II. The method of investigation 13

III. The laws of the circulation of water 16

IV. The root -system of plants and their role in the water regime

of the soil 24

V. The yearly water regime in the root-inhabited layers of the soil 28

The periodically or upper humid layer 29

The permanent humid soil layer or lower humid layer . 31

The intermediate dry layer 31

The permanent humid layer 33

VI. The appearances of drought 35

VII. Measures for contending against drought 43

320867

Detected errata in translation.

For the terms -„black, bare and ploughed fallow" -is to be understood
fields which are ploughed after the harvest in autumn and left unoccu-
pied through the following year until winter plants are sown in the follow-
ing autumn.

For the terms — ^spring and winter corn" — red „spring and winter
growths".

The frase is left out on page 6, line 38 of motion „and the

liquid water found on the surface of the layer is also transformed into
a hard condition and consequently cannot move".

Pages Lines Printed It must be

1 32 and i. e.

2 1 so with the „Nature of drought" so the essential of drought
4 of manure of black mould

6 of fibrous of alluvial

4 la. 4 of manure of black mould

31 are proof can hold out

32 Local District

5 10 forestry their forestry

„ 34 of 1890 of the eighties

6 8 the direct controlling influence a direct controlled determina-

played by tions of

8 21 comes in early appear suddenly
22 the sub-surface the surface

9 20 of deep of various depths
39 snow-water soil -water

10 19 dinimish lower the level of
26 sub -soil soil

11 18 consideration condensation
34 in is

41 frequent limited

13 15 90 20

18 2 m.m. 2 cm.

14 22a. 28 circumference volume

II —

Pages

Lines

Printed

It must be

15

15

layer under

layer 1 or 2 metr. and more

„

31

unmowed

unsowed

-

37

the decisions of the
partament

control de-

subsequent verifications in late
years

23

26

1094

1904

26

11

Uoung soots

young roots

29

15

position

position downwards

31

15

irrigation

agriculture

32

10

is

in

14

under

above

33

9

sid

rid

28

precipitation

fall of atmospheric water

38

thick

thin

35

15

gets

acts

36

20

on

including

„

26

moist

deep

37

31

treecourse

three course including

38

11,

27, 31 water

useful water

39

26

10

70

42

his

this

40

21

high

light

41

10

of farms

of field culture

^^

15

about

above

42

1

The presence of drought

The „nature of drought"

^,

2

of spring

of autumn

„

21

in an insoluble con

dition

undissolved

43

24

the threathing

the thrashing

45

1

every

every pood

28

of the form

of the field culture

^,

37

from

theirefrom

46

18

the farming thickness

the good thickness

PREFACE.

The present treatise forms a continuation of my previous
work intitled „The circulation of water in the soil of the Odessa
Experiment Field" which first appeared in the „Review of
experimental Agronomy for 1904 and later in 1907 in the
form of a separate pamphlet based upon my report in the
Odessa experimental field.

When the material, gathered up to 1904, concerning
soil humidity was subjected to analytical investigation, many
sides of the question were not then so clear so they are at
present. The intimate relation between the phenomena of plant
growth and soil humidity, their dependence one upon the other,
was so apparent that it was scarcely possible to work upon
one question without entering upon the related study of the
other. Commencing my investigations into soil humidity in 1895,
I found myself obliged in 1897 to take up the study of the
morphology of root-systems as applied to our cultivated plants —
their dimensions, the tendencies of roots of different orders,
and their distribution in the soil. So that it was not until the
year 1904 that 1 felt myself on firm ground and from that
time up to 1909 in a position to clear up the most impor-
tant points of that Section forming the subject of my treatise
„The root-system of cultivated plants of one year's growth"
which was published in the same year (1909). In this way
both questions — soil humidity and root-system both recei-
ved parallel investigation from 1895 to 1909, a period, of
fifteen years.

It was natural, of course, that certain phenomena con-
cerning the circulation of water in the soil could not become
clear to me, until I had grasped the part played by root-
systems in that process.

And as drought entirely depends upon certain laws of
water distribution in the soil and the lack of water in cer-

tain soil -belts, so with the „ Nature of drought" — its chara-
cteristics appear when studied in connection with types of soil
approaching that of the Odessa experinnental field a choco-
late colored clay containing from 3 to 6 per cent of manure.

However, the attention of the reader of my results may
be transferred to all blackearth soils resting on beds of fi-
brous clay such as the Russian steppe belts of the south and
the black-earth governements of the East.

During the last two years 1 have demonstrated the dia-
grams of the annual course of humidity embodied in this
treatise to very many people attending the Odessa experi-
ment field. They all insisted upon the quickest possible publi-
cation of my results, but it is only lately that all the details
of the desired work have fully developed. Circumstances outside
my control have hurried the publication of this work so that
certain parts lack somewhat in completeness. I consider it my
duty to express my thanks to the former supervisor of the
meteorological station on the Odessa field, K. N. Verzilow,
who gave me m.uch assistance in investigation soil-humidity
of root-systems.

y. I^ofnj/sfrow.

I. The state of the drought question.

..Drought and the means of striving against it" — in an ever-active
theme as ancient as agriculture itself, and much has been written on this
subject: for unbroken drought in some districts and, periodical drought
in others, prevents the agriculturalist from working peacefully and always
leaves him in a helpless position; for even now the means of preven-
tion are far from decided upon, inasmuch as drought itself, the na-
ture of drought has not been explained. At times it seizes upon great
areas — tens of million of acres or again limits itself to a trifling area.
They appear on the plains of Russia with singular force and persistence;
but here they carry quite an individual character frequently blighting
separate districts, separate farms.

The latter case — drought in separate farms — offers peculiar interest
inas much as it shows that drought may be a local phenomenon
limited to a given farm with its faulty peculiarities in the technical pro-
cess of farming. Should these faulty peculiarities of technical farming
affect whole districts then the droughts becomes not a local, but a ge-
neral phenomenon. For that reason the means of contention shoued bear
a local character only in regard to separate farms; and only certain parts
L'f them should be applied to such as may come under the influence of
the governement or district for the attainment of simultaneous and simi-
lar treatment.

The most detailed account of drought and the means of contending
against it was first give by A. Shishkin about 40 years ago.

He brought down the means of contending against drought to the
following points:

1) To establish, if possibls, connection between the bed-water and
the soil layer.

2) Deep mellowing (the mellowing of the sub-soil should be re-
peated approximatively every 5 years) of the soil for the greater accu-
mulation and better storage of water for better developement and deeper
penetration of the roots and for the attainment of firmer structure.

3) In the corporation of the soil a structure expedient for regulating
the penetration and evaporation of water.

— A —

4) Increasing the quantity of manure in the soil to improve the
relations betweens soil and water and to obtain more durability of structure.

5) Manuring the soil with dung, artificial manure and salts for the
accumulation of manure in the soil: for rich and more complete develop-
ment of roots and for more productive expenditure of water.

6) Seasonable tillage of fields for a larger accumulation of humi-
dity in the soil.

7) Constructing open ditches and using the mole-plough instead of
the ordinary subsoil plough to catch running water more completely.

8) Introducing ploughed fallow for accumulation more humidity in
the soil.

9) Using implements for spring tillage which do not turn over the
upper layer.

10) Early promotion of spring sowing in order that plants should
reap greater benefit from the humidity accumulated during winter and
give shade to the soil more quickly.

11) A perfect system of sowing and unremitting attention to plants
during growth.

12) Suitable selection of cultivated plants, species and seed and a
corresponding suitability of cultures.

13) Improving of productiveness of fallow-land and.

14) Looking out for lands lowly situated where there is a supply of
ground water for cultivating lucern, esparcet and rhizocarps.

All the above measures may be arranged in the following main
groups :

1) The adoption of mechanical tillage of the soil.

2) Improving the properties of the soil by chemical means.

3) Capillary raising of ground — water to the roots of cultiva-
ted plants.

4) Accumulating water in the soil by means of open ditches.

5) Selecting cultivated plants which are proof against drought.

6) Local steppe forestry.

I dwell upon the details of A. Shishkins work because most of
the later writers give preference to this method of contending against
drought.

Thus, P. I. Kostichew points out as a measure of fighting against
drought, that during autumnal ploughing in order to accumulate autumn
and winter reserve water in the soil, thus „for the protection of plants
against drought it is necessary to bring the soil into such a condition
that it is able to preserve better and hold more water out of a usual

quantity of rain", to this end the author advises the extirpation of weeds
in their initial stage, the destruction of crust on the surface by means
of harrowing etc.-- identical measures recommended by A. A. Shishkin.

P. F. Barakow also recommends measures very similar to those of
A. A. Shishkin.

His views are as follows:

1) The strictest possible preservation of forests and steppe silvicul-
ture, especially in the form of protective plantations.

2) Forbidding the tillage of steppe declivities of valleys and
forestry.

3) Irrigation of the steppe by the aid of running water and especially
by means of the retention of snow and snow-water (the watering of mea-
dow land).

4) Diminishing the area of ploughing and enlarging the meadow
and hay fields by means of artificially sowing grass seed.

5) Improving generally agricultural technic, and above all introdu-
cing a rational working of black fallow, which is 'he corner-stone of
steppe farming, and depends entirely upon a timely — that is to say as
early and at the same time as deep as possible tillage of the soil
(black fallow).

6) The introduction of farmyard manure, not only in order to enrich the
soil straight away with nourishing matter — azote and phosphoric acid,
minute quantities of which undoubtedly exist in the soil, - but also in
order to save moisture and economise in the expenditure of it by the
plants themselves: the dung being previously applied in the form of a
pall or covering.

7) Correct rotation of crops requiring the utmost diversity of
culture, especially leguminous (beans) and thorough ploughing plants.

8) Improving the sowing seed, by means of carefully selecting, clea-
ning and sorting them.

Comparing the above with A. A. Shishkins propositions we find the
following novelties; prohibiting ploughing on the declivities of valleys and
the retention of snow on the fields. As regards the accumulation of snow,
this question was raised at the end of 1890.

P. J. Kostichew and P. A. Barakow strongly supported the idea of
making use of accumulated snow as a means of fighting against drought
and worked up the question very completely.

At that period many authors dealt with this theme. It was sugge-
sted, that fields should be enclosed by living hedges being constructed
at a distance of 23 yards from one another (Kostichew), the rearing of

— 6 —

tall plants the stalks of which should remain standing over winter (Ba-
rakow, Batalin), even ploughing over snow, making furrows to hold
later snowfalls; and sowing over the winter land spring plants — such as
mustard —which would hold the snow between its stalks withered by the
winter cold (Batalin).

All these propositions regarding the utility of accumulated snow ba-
sed themselves on logical considerations without taking into consideration
the direct controlling influence played by the moisture in the soil
when under a pall of snow at certain periods, commencing in autumn,
continuing through winter and finishing in spring

Then the forced, as it were, cultivation of tall-stalked plants not
always suitable to given climatic conditions and the problem of organi-
sing plans for each farm, did not find acceptance, and the expectations
based upon accumulated snow have not been justified up to the present.
And if there are still defenders of these old principles, it is only because
they are founded on the easily misleading proposition: — that melting snow
is almost wholly absorbed in a liquid condition into the soil and raises
the quantity of water held there to a considerable extent.

It is out of this supposition • — that snow water saturated the
soil — that the misunserstanding arises. And I shall dwell on this mat-
ter rather fully in order to dissipate any misleading ideas regarding the
process of snow thawing in spring and its absorbition into the soil. This
comes so much easier for me to do, because the Odessa Experimental
Field carry on investigations into the temperature of the soil at the fol-
lowing depths: — o (on the surface), 2. 6, 10, 14, 20, 40 and 80 cm. In the
ploughable layer there are therefore five thermometers that is to say there
is all the data required for the most accurate explanation both as regards
the melting of the snow as well as the thawing of the soil.

It is only possible for snow to lie on the fields in a case where
both snow and soil have a temperature below zero. If the soil had a higher
temperature its warmth would be transmitted to the snow, which would
melt by degrees, the resulting water being absorbed by the soil.

We may observe this in autumn, when snow falls on unfrozen
ground. Then the snow thaws quickly. Up to the commencement of spring,
the soil layer freezes to the depth of one metre and more, in Central
and Nothern Russia, and to 40—50 — 80 cm. in the South. Throughout
the frozen layer the temperature is so low that water finds itself in a
hard condition and consequently incapable of motion. Briefly, so long as
the frozen layer does not attain a temperature above zero, the water
therein remains hard and motionless; and so long as the snow holds
out, the temperature of which^ of course, is always below zero, the upper

7 —

surface of the soil-layer is protected against any invasion of warmth from
the air; and underneath, the temperature of the whole frozen layer is also
below zero, the cold from thence travelling upwards. Therefore the upper
surface can only thaw when the snow attains a temperature above 0",
that is, turns into water. Now even if a part of this water penetrates into the
minute cracks in the depths of the soil, it will be turned into a solid
state and arrest the trickling water from above. At the same time, the
water on the surface of the soil gets warm, a part evaporates in the air,
and a part warms the lower layer of soil and water, raises the temperature
and saturates the thawing belts of land.

The whole question, therefore, comes to this: how quickly does the
soil thaw and how much snow-water succeeds in percolating. If the
thawing of the soil only proceeded from below upwards, then it might
happen that all the snow-water would be absorbed.

But // not only proceed upwards; but downwards as well from above
simultaneously.

To illustrate this I have traced the course which the process of
spring thawing took in 1907 in the soil of Odessa Experiment Field [fig. 1].
In general this process runs just so every year, the only difference being
the thickness of the frozen layer and the time the thaw commences: in
in the south it sets in earlier; in the North — later.

February

20 n

March

Fig. 7. The proccess of thawing of the soil in spring.
(The frozen layer is hatched).

Up to the 20-th February the thermometers showed that the soil
had frozen to 80 cm. from the surface [the frozen layer is shaded].
On the 20-th of February the layer thawed to 14 cm. from the surface,
and the rest remained frozen. From the 1-st to the 8-th the same layer
of 14 cm. was again frozen up. On March the 9-th the layer thawed
again to 10 cm. and on the 10-th of March to 14 cm. and remained
in that condition until the i-st°f April.

— 8 —

The lov/er layer commenced to thaw on the 26-th of February, when
the thermometer rose above 0° at a depth of 80 cm. At a depth of 40
cm. the thermometer remained below zero until the 4-th of April. This
temperature evidently extended deeper than 40 cm. until the 4-th
of April.

After the 1-st of April the upper part of the frozen layer began to
thaw quickly, getting ever thinner, so that by the 3-rd of April it was
no thicker than 10 cm. and lay at a depth between 35 and 45 cm.
On the 4-th of April both processes of thawing, the upper and the lo-
wer, met at a depth of 40 cm. and all the thermometers on that day at
all depth rose above zero. And all the water in the soil -layer turned
into a liquid condition.

Many years direct investigation of soil moisture at a period of full
thaw — this moment always coincides with the commencement of spring
field work has not shown any quick movement of soil water from the
upper belts into the lowers ones; and this alone should prove that very
little snow-water had found its way into the soil. As far as I know no
statistics have been furnished on this matter.

A small accumulation of water, about 3 to 4 per cent, in the
upper belts near the surface to a depth of 10 to 20 cm., may be obser-
ved in certain years, when spring comes in early. But if the thaw is
protracted, owing to a cold spring, the sub-surface gets extremely dry.
And by the time spring work begins, we find less water than there was
during the course of the winter.

The accumulation of large masses of snow in woods and especially
in artificial steppe plantations in the form of narrow strips or belts, give
a somewhat different effect. Here the snow holds out one or two weeks
longer than on the neighbouring fields; and when the soil of the conti-
guous fields has already thawed at all depth, it is still in a frozen con-
dition in the woods, under the snow. Water from the melting snow in
the woods getting into the soil on the boundary between the frozen and
the thawed parts is almost wholly absorbed and serves as a sourse for
the accumulation water for the forest.

J. Jukow recommends strewing ashes over the surface of the
snow in strips; and affirms that under these strips the snow melts quicker
than it does on the neighlouring clean snow strips, and that by this
means the snow-water is imbibed into the soil. Of course, if there was
no evaporation, the water thus formed would remain on the surface until
a certain thickness of the soil layer thawed. But the process of evapo-
ration is a reality and is particularly powerful in spring. Towards the
period when spring tillage commences the ash-strewn strips dry up and

_^ 9 —

the others remain damp and we get unequal sprouting. This one cir-
cumstance is sufficient to show the impossibility of using these means of
watering the soil, for such a motley on the field would exclude every
possibility of having the field work done in good time.

I have dwell on this question because much that is improbable and
fantastic has gathered round it without having been proved by accurate
and reiterated investigation of the moisture in the soil; and also because-
up to the present, serious importance has been attached to the accumula-
ting of snow on fields with regard to the question of fighting against
drought. In the extreme southern zone, about 100 versts from the Black
Sea, this means of fighting against drought has less importance as there
is little or no snow there in winter.

Resuming our deliberations on the rest of the proposed measures I
shall stop to examine some of A. Shishkin's as he has touched this ques-
tinn from very various points of view.

Deep mellowing of the soil which all the writers on this subject
unanimously regard as a matter of a great importance with regard to
fighting against drought, has also very little real significance. On the
Odessa field there have been more than 1000 experiments made on
the effect of deep ploughing for winter and spring crops, and no difference
in favour of deep [lO''-.' inches] or even mediate ploughing [7 inch.] was
obtained in the harvest. Investigations into the humidity of the soil also
showed no difference in that respect between deep and shallow [3' 2 inches]
ploughing.

The argument in favour of deep ploughing, that deeply mellowed
soil imbiles more atmospheric residue, falls through, because little residue
settles on the sfeppe districts and it all enters the soil whether deeply
ploughed o- not. On certain types of soil und in more northern regions
deep ploughing may have a beneficial effect for other reasons - airing
the soil etc. — but not as regard opposing drought.

As for manuring black-earth, which drough attacks very severely,
with dung and mineral manures, this question even now, abont 40 years
after the appearance of A. Shishkin's work, is not solved decisively. And
this is good proof that the effect of manure on black -earth is not so
telling as on other soils. Experiece with manuring on southern fields
points to a negative answer to this question. A more probable explana-
tion of the reason why dung acts negatively may be thus: -that the
higher concentration of liquid in the soil, by introducing manure into it
from outside, when there is very little reserve snow-water, brings with
it a diseased condition of the plant organisms. And this, instead of raising,
may even diminish the crops, as practical observation proves often enough

— 10 —

The choise of hardy, drought proof [xerophilous] plants or species
may undoubtedly weaken the withering effect of drought, but only to a
certain extent. At present this measure against drought is mainly theore-
tical, inasmuch as practical farming has set apart only bearded winter
wheat [triticum vulgare, cereale hybernum] and edible 6 - rowed barley
[Hordeum vulgare genuinum] as being more hardy and at the same time
more prolific. At the preseut moment it is difficult to say what a well
follov/ed np selection of plants would give us as regards xerophilous
forms. One consideration however must be born in mind: -that in moist-
years the drought resisting qualities of the plants would be thown away;
and if there was a run of 3 or 4 such years then those qualities might be
lost entirely. To preserve the xerophilous type in all its purity is would
be absolutely necessary to have a reserve of seed, therefore, for several
years, and, this is not adaptable to detached practical farming here, with
its settled organization.

Steppe arboriculture as a means of fighting against drought, seems
to have lost favour within the last decade. Investigation [H. Morosow,
N. Adamow, H. Wisotzkii, P. Ototzkii and others] has shown that „woods
dry up the sub-soil intensively, diminish the ground-water, thickening it
in salt solution, and on the neighbouring fields, especially on those sur-
rounded by woods they not only fail to equalise, but quite noticeably
increase the daily variation of temperature [Wisotzkii]. Then again seve-
ral failures with regard to steppe arboriculture created a certain bias
against it. It may be that this came about through the steppe arboriculture
itself having been put on a different level to that required by certain
considerations. With cur dry steppe sub - soil and extremely deep -lying
ground water one cannot count upon success in creatingforest as thickly wooded
as those in northern regions. A few years after the trees have been
planted, owing to the extreme thickness of the interlaced roots, the re-
serve soilwater disappears, and as the atmospheric residue of water is
insufficient the trees perish through drought in the deep soil layers.

Steppe arboriculture must be understood as tree-planting and the
most rational way of undertaking it is to arrange the trees in one or two
rows, not more. They are then able to benefit by the moisture from the
belts of soil contiguous to both sides of the rows of trees.

Then it is necessary to bear in mind another circumstance: that
trees, even if only a scant, single rowed plantation, minimise the injurious
effect of wind, which acts so destructively on unprotected steppe growths.
If the deep soil layer, which is out of reach of annual cultivated plants,
has a paucity of water under tree plantation, all that water evaporates
in to the air the humidity of which increases and at the same time in-
creases the chance of rain.

— 11 —

In a word, tree plant ant ion, but not in the shape of thick woods
shows itself to be a powerful weapon against drought.

With regard to A. Shishkin's method of accumulating water in the
soil by means of open ditches, one must treat it as a theoretical consi-
deration only for it is too expensive and therefore unattainable.

Amongst the others methods of fighting against drought A. Shishkin
mentions: — „Establishing if possible connexion between the ground-water
and the soil-layer" for the purpose of leading the ground water into the
upper soil belts. It is scarcely necessary to speak seriously of raising the
ground water on the steppe, where it lies at a derth of 140 feet and more
and when the only possible way is by capillary action. Kembell's s'milar
notion of capillarily raising, not the ground — water, but the sub-soil wa-
ter, will also not bear criticism, and is not confirmed by statistics. I shall
not stay to analyse the capillary raising of water in the soil here in the
introductive port of this work, but shall do it later in a chapter on the
movement of soil-water.

Several authors [Golovkinski, Bliznin, Barakow and others] point to
the consideration of watery vapour in the so'l as a condition favourable
to restrain or check drought. They consider that as a conseqnence of the
fluctuation of temperature in different depth of the so'l and the resulting
change in the elasticity of the vapour thereby the latter condenses into
liquid drops of water. Golovkinski in his experiments used a glass vessel
which he buried in the soil; expecting that the accumulated water in
the soil above the vessel would penetrate deeper and would be collected
in the vessel. Water was, in fact, found in the vessel but as my expe-
riment have proved this water came from condensation of the glass walls
of the vessel and funnel placed above it: for in the soil belt nearest to
the upper edge of the funnel there was no humidity, even approching a
saturated condition, from which alone liqnid drops of water could trickle
down. A. Lebedew brings certain statistics regarding water in the sandy
dunes of Anapa [of North Caucasus] bnt whether this water was an
atmospheric deposit or condensed from air vapour has not been proved
experimentally. Even if vapour condenses into liqnid drops in the soil
the process in very insignificant and in reality does not effect the balance
of soil water. But it is possible in spring and autumn when on the one
hand, the difference between the deeper belts and cooling of a'utumn
and heating of spring on the other may be considerable that water may
be precipitated and condensed on the boundary between them.

An analysis of these proposed measures of fighting drought has
shown that they do not appear reliable and further that they do not
clear up the nature of drought, the reasons of its frequent appearances
and do not give solidity to the comprehension of the interdependence

-— 12 —

between the technical methods of agriculture and their effects on the
water regime of the soil. The lack of sufficient statistics on the humidity
of soil, or various methods of investigating soil-water in the root inha-
bited soil layers and as a consequence of this the ignorance of the
laws regards the circulation of water in the soil made it difficult to
gather deductions regarding the latter or which is the same thing regar-
ding the phenomena of drought.

The Odessa Experimental Field has several thousand sets of sta-
tistics at its disposal got together in the course of 15 years. And this
makes it possible, in my opinion, to get nearer to the truth.

II. The method of investigation *).

In every experimental 'nvestigat^on, method is the deciding factor;
and the incontestability of the facts gained hereby, depend entirely upon
the directness and the nearest approach to truth, of the method adopted.
It is therefore necessary first of all, to consider the adaptatibility of the
method, to the work before us.

In studying the humidity of the soil, investigations kept to the
method of average quant'ties, in the first period of their treatment, of
this question during the lact two decades of the past century; (A. A.
Ismailsky and H. I. Bliznin amongst others.

By this method, evidence as to the state of soil - humidity may be
obtained if a sample from a layer of soil of a certain thickness, be
obtained in such a manner, that it shall contain a similar quantity of
soil from all parts of the layer; which means, that a column should
be taken from the soil, of a length equal to the thickness of the layer —
from the surface to a depht of 10 cm., from 10 to 90, from 20 to 30,
and so on, or from the surface to 35, from 35 to 50 cm. e. t. c; and
as the weight-should not particularly heavy — from 20 to 30 gram — the
thickness of the column should not exceed 1 or 2 m.m.

If the experimenters in this method, had made use of samples,
taken from the vertical walls of open pits, they coold have taken an
equal proportion from each layer at all levels and the samples would
then, have held a similar quantity of soil from each horizontal depth.

But pit-digging comes expensive and takes up a great deal of time.
So that instead of th's inconvenient method of selecting samples, a
soil-borer is used. Those investigators who adopt the method of average
quantities use, for significant thickness of soil-layer borers, wilh a long
spoon or trongh, split down its entire lengtn of from 10 to 15 cm. The

^■") Here, thismatter is treated as briefly, as possible, but it i may be
found, worked out in detail in my treatise. ,,The circulation of water in the
soil of the Odessa experimental field", published in 1904 (the Journal of expe-
rimental Agronomy. Book VI), to which I refer all those, who are interested
in this branch of my work.

— 14 —

soil borers of Voislava and Bliznina, belong to this type. They have
however shown themselves to be utterly unsuitable, for the simple reason
that soil enters the spoon in so promiscuous a fashion as to preclude
any possibility of making an accurate partition of that which falls into
the spoon, through the slit, and from which, the sample is obtained by
cutting a certain thickness of the layer, the whole length of the slit. It
may happen, that soil particles from only the upper and lower layers of
the bored depth — or from only the middle impinge against the slit; in
short there is not, and cannot be any assurance that an equal quantity
of soil from all depths passed through, by the borer will get into the
sample, through the slit. Therefore a sample selected from the spoon
cannot be an average for the pierced depth; it may show a much larger
or a much smaller proportion of water, than the average for the whole
penetrated layer depending upon whether more soil, from the moist or
from the dry strata, gets into the slit of the spoon. Another objection to
the spoon — borer, is that it collects the soil in a very compact or com-
pressed condition; and if the ground under investigation contains a large
quantity of water, the compression of the soil will cause a part of that
water to be pressed ont of it. This water will undoubtedly take the line
of least resistance; which means, the slit of the spoon-borer. Therefore
in a sample collected from the slit may be fomed water pressed ont of
the whole circumference of the spoon, in consequence of which, a
sample may be obtained containing a lot of water from a moderately
moist soil. On the other hand firm ground, containing an insignificant
quantity of water, will give a sample with still les water in it; for the
friction caused by the spoon-borer in piercing firm ground, is so great,
that it may be heated to 60 or 70 degrees, and this entails the loss of
water, by evaporation in the whole circumerence of the soil, in, and
surrounding, the spoon on every side, and consequently heated on every side.
These two defects — the impossi bility of getting an average example from the
bored depth, on the one hand, and the probability of always getting either an in-
creased or a dimished quantity of water in the sample taken fromthe spoon
on the other hand — condemn the use of the spoon-borer in investigating the
humidity of the soil with anything approaching accuracy.

Thus the idea itself the method of arriving at average quantities
of humidity in more or less significant layers of soil, turned out owing
to the adoption of imperfect soil-borers, to be infeasible. Indeed, work
carried out be this method has not cleared up the most essential factors
of the water processes in the soil. The method of getting the average
quantities of water in significantly thick layers of soil could not resolve
the main qnestions of the balance of water therein, inasmuch as it
could not deal with the limit line between layers having a plentiful and

- 15 -

those having a meagre supply of water; and it involuntarily glossed over
the characteristies of the distribution of soil water, which only themsel-
ves come out in the perceptible deviations of the contents of two, or
more contiguous soil layers.

The sharper these deviations are defined, the more they explain
the process of water distribution and it's circulation in the soil.

In order to explain these processes- distribution and circulation
it is necessary to fix a point of observation frow whence these processes
with all their modifications, may be kept in view for a long time.

These point of observation should be fixed at certain depths of
strata in the ground in which, during the course of one or more years
accurate est-'mates of the quant'ty of water are carried out from time to
time, and if these layers are disposed as near as possible to each other
as regards depth, then every variation in the amount of water they con-
tain may be fixed accurately in the soil layer under investigat'on of
horizons lying as near as possible one to the other these principles 9 have
followed in my own work. I may add that in ieach horizons a layer of soil
was investigated 1 5 c. m. in thickness. To take a sample from such a
thin layer of soil with the spoonborer is not possible; therefore I con-
structed a soil borer of a special type which rendered it possible to obtain
a vertical sample at any depth of the bored hole by means of a ringshapod
cut in the walls of the hole. There also in the hole at the same depth,
the sample falls at once, into a zinc box which only closes in the open
air after having been taken out of the hole'-).

The method adopted by me, during a period of one or more years,
in investigating soil humidity, was the registration in a soil layer of 1 or
2 metres, of the amount of water contained in layers of 1 - 5 c. m. thick-
ness at every 5 or 10 c. m. That is to say that layers from 5 to 6 — 5 c. m.
10 to 11,5 c. m. 15 to 16,5 c. m. and so on, were kept under observa-
tion. The registration of humidity was carried out on fallow land, both
unmowed and under maize, potatoes, flax, pumpkins and castor plants,
then, unber winter wheat, barley, oats and other grasses; on unploughed
land lying fallow for many years.

The total number of estimates of moisture on the Odessa experi-
mental field, amonut to about 60,000, and should show themselves
ample for arriving at more or less precise results which have been
confirmed in every case by the decisions of the control department.

*) A more detailed description of my borer may be fonnd in my work
„ Circulation of water in the soil" Which also describes the whole technical side
of taking a vertical sample and of drying it.

III. The laws of the circulation of water.

In order to explain the phenomena of drought, it is necessary to
investigate the processes of water distribution in the soil previous to the
droughe, and to keep them under observation during the period of drought.
Undoubtedly this will be possible, if the laws of water circulation in the
soil be established, both in superficial layers and in deeper ones, but
accessible to the roots of plants.

Water circulates in the soil upwards, downwards and sideways.

As regards the circulation in an upwards direction, there exists a
wrong impression, which our literature has almost made a household
word. It is maintained that water can rise to the surface from the deep
layers by capillary action. I shall not name the authors who maintain
this theory — they are too numerous: but I do not know of a single
author who could prove this proposition. Of course, by „deep" soil layers
almost any measurements may be understood: 50 or 200 cm., 35 or 70
feet. But it must be admitted that deep layers, from which it is desired
to raise water into higher ones, are those, the water of which is inacces-
sible to the roots of plants unless it be raised: if it were otherwise,
there would be no object in drawing the water upwards, inasmuch as
the roots would get at this water, if it existed in accessible layers,
although perhaps not until they reached a somewhat late development.
Consequently by the word ,.deep" must be understood those layers into
which the roots of cultured plants do not strike.

The root-system of cnltivated plants and its role in the distribution
of water especially its upwards movement bu the roots will be treated more
fully belov/. As regards the mechanical raising of water however by ca-
pillary action it may be assured that the limit from which water can
make its way upwards, lies much higher than the limit accessible to
roots. All laboratorial experiments have shown that the upward movement
of water in dry soil due to the mechanical composition of the latter, is
comparatively very small for a given space of time — not more than a
few centimeters in coarse sand, and from 20 to 30 cm. in very fine soil.
In soil from the Odessa Experimental Field, sections of which were kept

— 17 —

in glass tubes about 10 sq. cm., water showed a rise of 82 cm. in three
m.onths. But a rise of only 30 cm. was observed in sections of 900 sq.
cm. (30x30) enclosed, in wooden boxes. Evidently, its circulation up-
wards by capillary action proceeded very slowly.

But it must be borne in mind that such a slow upward movement
of water is observed only when the bottom of the pile of soil is sunk in
the water, a condition scarcely ever observed in fields, where the ground-
water lies comparatively deep. On the steppe for instance it lies at a
depth of several tens of fathoms.

Direct observations of soil humidity, carried out on the Odessa Expe-
rimental Field showed, that in the course of l'-.' to 2 months drought,
a field with a compact surface void of vegetation, loses water in a layer
not deeper than 30 cm. But in the deeper lying layers, commencing at
40 to 50 cm. no decrease of moisture was observed. And this period
gave ample epportunity of seizing the phenomena accompaning drought,
for a ramless couple of months is an actual drought in every sense. If a
process of raising soil-water by capillary action from significantly deep
layers, really went on in fields, it could, be determined or registered.
And this could be done all the more easily if the humid layer diminished
in thickness, for then it would be possible to affirm with confidence that
the whole of the humid layer had been transferred upwards; and an im-
poverishment of water would be observed precisely in the lower belts of
the humid layer. If such a process of raising or moving soil-water up-
wards existed in nature generally, it would not only be possible to verify
it during a period of drought, but as a result of the action of roots; and
in that case the absorption of water by the roots in the upper and mid-
dle parts of the humid layer should be reflected in the lower parts in
the shape of a diminished ratio of water. But during the course of fifteen
years observation on the Odessa Experimental Field no such facts have
been brought to light; for when the ratio of water diminished in the lo-
wer parts of the humid layer, an impoverishment of the water in the
middle and upper parts was simultaneously observed. Therefore the
existence of a well ordered, simultaneous circulation cf water at all thic-
knesses of the humid layer cannot be confirmed. It is only those layers
into which roots penetrate that lose water, and the thickness of the
impoverished and partially dried layer corresponds to the length of the
roots in the soil; thus, if winter wheat be sown in a field under black
fallow having stored up v/ater in a layer of over two metres, there will
be found by harvest time, an impoverished layer of from 120 to 130 cm.;
for this depth is the limit required by the roots of winter wheat for their
development (table I).

IJ

Table T.
Winter wheat on bare fallow ploughed 10' l in deep.

CO

-^

t^

lO

»o

r^

^

"Z »2

B
o

>
o

S

o

CD
Q

>-3

o

•^

'E
<

CO

3
>-:)

5

19,2

7.2

20,3

18,8

20,5

20,2

16,3

10,0

9.1

13.8

10

20.4

11,3

20,0

19,2

20,4

19,1

16.6

11,4

10.1

9.8

15

19,9

15.6

16,5

18,4

20.7

19,4

17,7

12,3

10.5

9.7

20

20,1

17,3

19,7

18,0

20.8

19,0

18,3

12,6

10,8

10.6

25

19.4

18,4

17,8

19,3

20,6

19,2

18.6

12.4

10.6

10.5

30

18,8

16,5

17,1

20,1

20,6

18,7

18.1

12,5

10.7

10.5

35

18.0

17,1

17,2

18,7

20,0

18,2

17.6

12,6

10.5

10.4

40

17.5

16.4

16.7

18,3

19,3

18,4

17.3

12.8

10.4

10.4

45

17,3

16,3

15,5

17,6

18,5

17,4

17,4

13,7

10.4

10.2

50

16,8

16,3

16.0

17.2

17,9

16,7

17,1

13.0

10.4

10.4

55

16,8

16,4

15,9

17,3

17,2

16.1

16,8

13,2

10.2

9.9

60

16,9

16,1

16.0

16,7

16,4

16,1

16,7

13,7

10.2

10.0

65

16,7

15,5

15,6

16,5

16,0

16,0

16.3

14,0

10.3

10.1

70

16.7

15,9

15,8

16,0

16.0

16,0

16.9

14,6

10.3

10.3

75

16,1

15,3

16.0

15,6

16.1

16.1

17,1

14,2

10.6

10,6

80

15.8

15,1

15,9

15,4

16.3

15,5

16.6

14,1

11.0

10.8

85

15,1

15,3

15.4

16,0

15,3

15,8

16.6

14,2

11.0

10.8

90

15,9

15,6

15.8

15.8

15.6

15,5

16,1

15,2

11.2

10.9

95

14,8

15.6

15.6

15,6

15.9

15,5

16,7

15.3

11.4

10.8

100

15,3

15.4

15.9

15.6

16,0

16.2

16,4

15,6

11.5

11.1

105

16,0

15,3

15.4

15.6

16.0

15,5

16,1

15,7

12.4

11.4

110

15,8

15,5

15,5

15,2

15.7

—

16,3

15,5

13.0

11.6

115

15,7

14,7

15.6

15,2

15.5

15,9

15,5

15,5

14.0

11.6

120

15,5

15.4

15.3

15,4

15.8

15,5

15,1

15.7

14.8

11.9

125

14,8

15,5

15.0

15,5

15,1

15,4

15,2

15.7

14.8

12.4

130

15,4

15,1

15,0

15,4

14.5

15,1

15,0

15,5

14.5

12.5

135

15.7

15,0

15.1

14,9

15,0

15,0

14,9

14,9

14.1

14.8

140

15,5

15.3

14,9

—

14.8

15,0

14.7

14,6

14.1

13.7

145

15,4

15,2

14,8

15,0

14,8

15.0

14.9

14,0

14.0

14.1

150

15,6

15,0

14,8

14,8

14,8

15,2

14.8

14,5

14.1

14.2

155

14,5

14,9

15,0

14,7

14.8

14,9

14,8

14,0

13.8

13.9

160

14,7

14.7

14.7

14,6

14,8

14,7

14,9

14.3

13.9

13.8

165

15,5

14.6

14,5

14,3

15,3

14,9

14,1

13,9

13.7

13.8

170

15,5

14,3

14,6

14,0

15,0

14,9

14,6

13.7

13.3

14.1

175

15,3

14,2

14.3

13,0

14,6

15,0

14.5

14.2

13.4

13.5

180

15,4

13,9

14,4

13,8

14,6

14,7

14.2

14.9

13.1

14.0

185

15,6

14,4

14.3

13,7

14,3

14,7

14.1

14,1

13.0

13.4

190

15.3

14,5

14,3

13,6

14,4

14,6

14,3

13,9

13.1

13.1

195

15.2

14,3

14,1

13.8

14,1

14.7

14.5

13,8

13,4

13.5

200

15,3

14,1

13,9

13,8

14,3

14,5

14,3

13,9

13.3

13.5

— 19 —

How the process of the upward transference of water in the soil
is carried on, under conditions of a non-saturated soil, and in the ab-
sence of an available sourse of water in the immediate vicinity that is
to say whether the water gets to the top in a liquid or in a state of
vapour-it would be difficult to say with certainty in the present state of
this question with its lack of precise evidence founded on fact.

But there is one consideration which tells in favour of the mo-
vement taking place in a state of vapour and not in the state of liquid drops.
It is the following: — the so called capillaries in dry soil form an extre-
mely irregular network of hollow spaces of various, size and shape. They
do not resemble in any way those glass capillaries or tubes which
are used for experimental purchases in the laboratory and with which
they are usually compared. For the glass walls of these tubes prevent
any air from entering from the sides, a condition which does not exist
in the soil; and for that reason the condition of water circulat'on in so;l
contained in glass tubes will be different from that in the soil of open
fields, In a strict sense, capillaries or „tubes" as some authors call them,
no more exist in the soil than they do -to give a familiar example — in
a heap of small-shot of various sizes, which, with their interstices, may
be compared to the soil. -- When the soil is not fully saturated with
water — and this is always the case in fields — a certain proportion of the
interstices between the particles are filled with air. and the others with
water; in consequence of which water is found in these interstices :n the
form of separate drops cut off one from an other by air. If under any
circumstances whatsoever an upward movement appeared in a signifi-
cant thickness of soil, that movement could only concern the more mo-
bile parts viz: the air, which circulates in the free empty spaces not
taken up by water — and the drops of water could remain where they
are: or because of their weight sink downwards. All these considerat'ons, and
the absence of facts to the contrary, lead to the conclusion that an up-
ward movement of v/ater only goes on in soils saturated with water;
whereas those in a non saturated condition suffer a loss of water whe-
rever a drop lies, by evaporation in the air surrounding that drop. For
this reason the loss of water in the superficial soil layer goes on very
slowley even when the layer is in a compact condition, Campbell's sys-
tem so much spoken of latterly, will not bear criticism in regard to its
main thesis: — increasing the capillary process in deep soil layers and
leading water from them up into those layers near the surface.

Compression with the subsoil roller causes the soil particles to
adhere closely, expels the air from their interstices, at the same time
satiating this compressed layer with water — and nothing more. It cannot
be doubted that the conditions for the growth of seeds, sown on such a

— 20 -

dense area, are improved thereby; inasmuch, as a certain portion of
water can be actually squeezed, into the upper part of the compressed
layer by intense pressure, and the seeds can benefit inmediately by this
moisture. So that subsoil rolling is beneficial only just before the sowing
of winter corn. As regards capillary ra-'sing of water from the deep layers,
the less said about it the better.

On the other hand the constant movement of water downwards,
both in the upper and lower, even in very deep layers, cannot be de-
nied. In my treatise of the circulation of water in the soil -). I gave nu-
merous examples of the downward percolation of water at big depths
from 95 to 105 cm. (3 cases) and an insigneficant depths -from 35 to
45 cm. (2 cases), at a speed of 15 to 20 cm. per month'-*) on old
ploughed fields and twice as slowly on unploughed soil.

All the data at my command regarding moisture on the soil of the Odessa
Experimental field, point only to one conclusion viz: that water percolating
beyond a depth of 40 to 50 c. m. does not return to the surface except
by the way of roots; all the water not seized by the roots goes down
into the deep layers, moving at the rate of about 7 feet yearly. In order
to verify this theory a pit was dug 1040 cm. deep on unploughed land;
that is on soil covered with vegetation. And as this pit lay in a hollow,
where rain water collected but had no outlet, there was a certain
surplus of water every year, which not being Imbibed by the roots, per-
colated into deeper layers, as stated above at a speed of about 2 metres
per year (table II). At 260 to 330 cm. remains of the previous years
1903, water were fonnd and at 460 to 530 cm. the surplus water which
had percolated thither in the course of 2 years (from 1902) previously.
If it be taken into consideration that the extreme limit of the Super-
ficial humid layer was fonnd to be at a depth of 130 cm., then the
foremost or leading part of the previous years (1903) humid layer should
have been abont 330 cm. deep but was fonnd at 330 cm. The fore-
most part of the 1902 layer should have been about 530 cm. deep and
was found at that depth. In both cases the remains of each year's wa-
ter have a distance of about 2 metres between them.

Therefore there is no doupt about the process of water transference
from above downwards and its significant preponderence over the pro-
cess of the supposed capillary raising of soil water to the surface. The
formation of ground water goes on, not only at the expence of water
oozing into the depths from ponds, hollows and snow water in planta-

■•) Circulation of water pp. 30 and 81.
"'■■''■•) Ditto page 32.

— 21 —

T;il>lo II.

■■i

centi-

_ X

«/o

1 1

O/o

Q S

0 '
0

/ 0

5

14.0

210

11.4

610

11.9

1010

14,3

10

16.3

220

11.4

620

12.1

1020

14.2

15

17.0

230

11,6

630

12.1

1030

14.3

20

17.7

240

11.6

640

13.6

1040

14.3

25

18.1

250

11.1

650

14.4

30

17.8

260

11.7

660

14.4

.

35

17.5

270

12.4

670

14.0

40

17.0

280

12.4

680

15.1

45

16.3

290

11.8

690

14.6

50

15.7

300

12.6

700

14.9

55

15.7

310

11.2

710

14.7

60

15.7

320

10.5

720

14,8

65

16.0

330

11.5

730

14.4

70

15.9

340

10.4

740

14.3

75

15.1

350

10.1

750

15.1

80

14.7

360

10.1

760

14.9

85

15.0

370

9.5

770

15.1

90

15.0

380

9.1

780

15.0

95

15.0

390

10.1

790

14.5

100

15.0

400

10.0

800

14.6

105

14.5

410

10.4

810

14.8

.

110

14.4

420

10.6

820

14.0

115

14.1

430

10.7

830

14.5

120

12.2

440

10.4

840

125

10,5

450

850

14.4

130

10.7

460

11.7

860

14.7

135

10.4

470

11.7

870

14.1

140

10.5

480

11.9

880

14.0

,

145

10.6

490

12.7

890

14.0

150

10.7

500

12.2

900

14.3

155

10.7

510

12.4

910

14.3

160

11.0

520

12.4

920

14.3

165

10.9

530

12.4

930

14.7

170

10.8

540

11.9

940

13.9

.

175

10.4

550

12.0

950

14.0

180

11.0

560

11.4

960

14.1

_.

—

185

11.1

570

11.9

970

14.0

190

11.5

580

11.7

980

14.3

—

195

11.2

590

11.8

990

14.2

—

—

200

11.1

600

1000

14.4

— 22

Tahle III.

8 pit-holes dug on lay-land at a distance of 35 centimetres one

from another.

Depth in centi-
metres

I pit-hole

1— (

>—<

IV pit-hole

V pit-hole

Y\ pit-hole

■&

1— (

>

rS

5

7.9

8.3

9.8

18.2

14.0

9.4

5.6

6.9

10

8,4

9,7

11,1

18,3

16.3

11.0

9.3

8.5

15

8.8

10.0

12,7

18.2

17.0

11.6

9.9

9,7

20

9.5

9.7

14.6

18.1

17.7

11.1

10.7

lO.O

25

10.2

10.3

15.0

17.8

18.1

11.8

10.9

10.9

30

9,9

10.3

15,1

17,8

17.8

11.1

10.8

10.9

35

10,0

10.4

14,7

16,1

17.5

13.1

11.2

10.5

40

9,9

10.0

14.2

17,4

17.0

13.6

10.7

10.4

45

8.0

10.2

14.1

15.7

16.3

12.0

10.4

10.3

50

9.8

9.9

14,8

15.3

15.7

12.1

10.2

10.1

55

9.9

9.8

14.3

15,9

15,7

12.4

10.2

10.0

60

9.6

9.8

14.3

15.2

15.7

11.6

10,0

10.3

65

9.8

9,7

12.8

16.1

16.0

10.6

10.4

10.4

70

9.7

9.7

11,8

16.1

15.9

10.2

10.1

10.5

75

9.7

9.9

11.2

15.5

15.1

10.2

10.3

10.6

80

10.0

10.1

11.2

15.6

14.7

10.6

10.6

10.5

85

9.9

10.0

10,7

15.6

15.0

10.6

10.4

10.7

90

10.4

10.3

10.6

15.5

15.0

10.6

10.3

10.8

95

10.4

10.1

10.5

15.1

15.0

10.8

10.8

10.7

00

10.4

10.4

10.4

15.2

15.0

10.6

10.6

10,4

05

—

10.5

10.2

14.3

14.5

10,7

10.6

10

_

10.4

10.4

14.3

14.4

10.6

10.5

—

115

—

10.5

10,5

13.2

14.1

10.8

10,2

—

120

—

10,8

10,8

11,0

12.2

10.8

10.4

—

125

_ .

10.5

10.3

11.4

10.5

10.8

10.5

130

10.8

10.0

10.7

10.7

10.8

10.1

—

135

—

10.8

10.2

10,8

10.4

10.7

10.2

—

140

—

11.0

10,2

10.8

10.5

10.7

10,0

—

145

—

10.6

10.4

11.0

10.6

10.7

10.2

—

150

—

10,5

10.7

11.0

10.7

10.8

10,3

—

155

—

—

10.7

10.8

10.7

11.0

—

—

160

—

— .

10,1

10.8

11.0

11.0

— .

— .

165

—

—

10.7

10.1

10.9

10.9

—

—

170

—

—

10.9

10.8

10.8

11.0

—

175

-

....

11,1

10,8

10.4

10.4

—

_

180

—

10,8

11.0

—

—

—

185

—

10.2

11.1

—

—

190

—

—

—

10.2

11.5

—

—

—

195

—

—

--

11.1

11.2

_

—

—

200

11.0

11.1

- 23 -

tions, as A. A. Ismailsky imagines, but as will be seen below, preemi-
nently from surplus water not used up by the vegetation on the surface.

Finally a third process of water circulation side ways, in a hori-
zontal direction undoubtedly goes on. In order to elucidate this process,
the following experiment was carried ont on the Odessa experimental
field on a piece of waste land in August when the soil for a certain
depth was dry. A fine jet of water (about 2 m.m. in diameter) from a
wooden cask was by means of a syphon turned on to a certain spot for
several days. Then, on a straight line drawn through the point to which
the jet of water had been directed eight pit holes were dug at a distance
of 35 cm. from each other, and samples were taken from all the pit-
holes at every other 5 cm. of depth. The following picture of water
distribution was secured thereby.

At similar d'slances from the source of the water, in pit holes I
and VIII a most layer at 25 to 35 cm. depth was found, in II and VII —
from 20 to 45 cm., in III — from 5 to 80 cm. But in VI, which occupied
an analogous position to III, from 5 to 60 cm. In IV from 0 to 125 cm.,
and in V— from 0 to 120 cm. (table III).

And as there was a distance of 122,5 cm. between the source of
the water and the edges of pitholes I and VIII, and as the water perco-
lated to a depth of 125 cm. it is evident that water was imbibed in a
horizontal direction on all sides for a distance equal to the depth of its
percolation downwards. Consequently, water diffuses itself in the so'l
horizontally, with the same energy as it does vertically.

In conclusion I must admit that the propos'tions which I put for-
ward previous (in 1094) regarding the circulation of water, somewhat
differ from those conclusions presented by me now, which have been
arrived at by subsequent evidence.

The real developement of „the critical horizon" as I then called it,
goes on precisely in that depth (50 to 70 cm.) where the formation of
a very large number of roots takes place; and falls in May or June,
when the greatest number of roots are first developed.

Clearly fhe crackmg of the humid layer at a depth of about 70 cm.
does not result from any cause of a mechanical character, such as
the raising of water by capillary action, but simply from the absorpt'on
of water by the roots of plants.

IV. The root-system of plants and their role in the
water regime of the soil.

It was stated above that the root-system of plants has an impor-
tant significence in the water regime of the soil.

But first I shall deal briefly with the root-system of various plants,
for without a knowledge of their dimensions and the distribution of small
roots it is difficult to explain the water processes in the soil ••).

. The roots of plants develope very rapidly after the germination of
the seed, and already in 7 to 10 days time after the appearance of the
sprouts they reach 35 to 40 cm. in our cereals, going far beyond the
limit of the average ploughed depth. At the beginning of the bushing
period the roots of spring cereals attain a depth of 50 cm. (fig. 2) and
towards the commencement of flowering the developement of the root-
system finishes, or the growth of the roots after that to the attainment
of maturity is insignificant. In the case of winter crops, a certain growth
of the roots goes on in the interval between the period of flowering and
the period of maturity (fig. 2).

This peculiarity the cessation of the root growth after flowering —
distinguishes cereal plants from flowers and dictoyledons, whose roots con-
tinue to grow after flowering.

Then cereals have a second peculiarity. They have always three
or more main roots (fig. 3) from which lateral roots branch off whilst
dicotyledons have always one main root (fig. 4). Then the main root of
cereals leave the root-head in a lateral direction, almost at right angles
one to another, forming a polyhedrous pyramid; whilst the main root of
dicotyledons grows vertically.

The limit to which the roots spread downward and sideways (the
dimensions of the root system of various plants their length and lateral
spread is seen on table IV") is very large towards the end of the vege-
tating period. — Spring cereals (fig. 5) reach' a depth of 110 c m. and

*) A more detailed account of root-systems is included in my work „The
root-systems of plants of one years growt".

p I

Kidney

bi'jins.

c5

s

15

26 25

30 40

28

64 65 100

64

96 104

9984

Trench
beans.

Q

15

28

35

12

Horse
beans.

Su

s

Q

40

46

48

24

28

62 60

85 60

5100

80

84

110 84

9240

Winter plants

Winter
wlieat.

Winter
barley.

Vicia
villosa.

RING

LAN

Twii-iiiv

Slllllllirl
IliUlc.V.

Summer
wheat.

Local
oats.

Canary
oats.

Summer
rye.

Setaria
italica.

Black
sorghum

Yellow
sorshum

Kidney

Trench
lieans.

Horse
beans.

Summer
vica.

White
poppy.

Came-

lina

sativa.

Sunflo-
wer.

Castor.

Cucum-
ber.

Ai the a|i|icnniiii'(' nf

LiWlllS

Ai UifheKinniiiKiifllie Inid-
ilinu' pcriiBl III herbaceous
Pliinls

.\l llie I)eg:iniiiiij5 iif tbeearing
period otherbaceous plant.s

At the beginnin;; of tbeflowe-
ling period

At the beginning of the ma-
lurafion iieriml (milky) of
hrrliawiins |ili\nts. .

Fliiiit tijctfirient (tlie i)ro(Uict
lit the lenglh of the root
by its diameter) .

../^■^ ■^<,..^.y ^

:v^-

£^' -yMS^^^

/^^/

.N. >^

V-^^

i^£i^

Fig. 2. parley (Hordeum uulgare genuinum.) at the bushing period.

^'sJ^

^^L

f;"\V,

/^/^. 2. parley (Horcleum vulgare genuinuni.) at the bushing period.

^

^

On blacl^soil. On sandy.

Fig. 4. Xucerq in the 1-st year before flowering.

i i

11^--

y^ m%

:yz^

'■. ',4f''' iM '^\ ■" '

/^/^. 5. Surqrrjer wheat „UlI^a" at the beginning of period of maturity.

' ■■■•■■ ^^'V

4 A -ijij^ }

Fig. 6. jyfaize of 76 days' growth. The upper half of the root-system

is reared on very humid soil, the under on somewhat dry.

(The hydrotropism of the roots).

>']

y'-

i/^n

' ' i T'•>..'•
>■• AJ^''

'A

On blacl^soil. On sandy.

Fig. 7. peas after the period oj flowering.

op.

/.^A:

OJo*n.A^^^

t^

\hV.

,J^^(^'^-\

\

Z^/]^. i^. ^eaqs at the period of fruit-bearing.

^ ^

lli

At the period of fruit-bearing.

Fig. 9. potatoes.

Of 7 days' growtli.

— 25 -

spread out to almost the same extent. Maize is an exception, for its root-
system is greater in width (up to 150 cm.) than in length. The root
system of winter cereals is longer than that of spring cereals and reaches
130 c. m. (rye). Then in wheat it is flatter from top to bottom, and in
rye it is stretched lengthways, Amongst dicotyledons, sunflowers and
beetroots haee very long root-systems (over 4h'-> feet): others like flax,
cress, poppies, peas (fig. 7), beans (fig. 8) and cotton have very short-
ones (about 100 cm.); potatoes (fig. 9) very short (about 60 cm.)

Cereals (fig. 5) have a much denser root network than dicotyledons
(fig: 4 and 7) which have a comparatively weakly developed root-system,
especially flax with small roots of the 2-d, 3-d and lower orders. It must
be noted here that t/ic thickness of the root network is almost equal thro-
ughout the soil layer which they occupy. But small roots are always
deuser in that layer which holds the most moisture whether it be the
upper, intermedeate or lower part of the root-inhabited layer (fig. 6).

Perennials like green fodder, shrubs and trees extend their roots
several fathoms deep, sometimes over 10; green fodder, like lucerne,
send their central root down to 8 even 10 fathoms; laterally the side
roots do not extend beyond 60 or 80 cm. The side roots of trees extend
from the central one to 5 or 6 fathoms, the white acacia (Robinia pseu-
dacacia) even to ten fathoms.

These morphological properties of the roots of our field plants must
be kept in view in order to understand the role played by them in the
distribution of water; for the principal, almost the only factor in that
distribution, is the root-system (as regards soil layers deeper than 50 cm.
at any rate). The denser the root network of a plant, the easier it will
be for that plant to find water of course. But plants with a weakly deve-
loped root-system, like flax and cress, must have at their disposal a
plentiful supply of water. This apparently explaius the preponderating
culture and independent growth of grasses on dry steppe areas, for their
denser root network can abtain the requisite quantity of water with gre-
ater facility.

The data worked out by me last year concerning the depth pene-
trated by the root-system of various plants of not less than 110 cm.
(31;'l> feet) for certain others much deeper — indicates that in order to ob-
tain an abundant harvest the root-inhabited layer of soil should be moist
throughout and should hold a sufficient quantity of useful water; that is
of water which the plants can benefit by. It must not be forgotten that a
certain quantity of water is contained in various soils which roots cannot
make use of. The finer the soil, the more useless water it contains, and
in certain types of soil it exceeds lO^/o.

— 26 —

The roots of cultivated plants cannot nnake use of this water, the-
refore in considering the percentage of water containd in the soil, this
factor must always be kept in view, for the figures „12"/()" may really
mean that in a given soil the useful water amounts to only 10, 8,
4 and even 2" 'o.

The soil on the Odessa experiment field holds about 10", 0 useless
water and in the following statements the serviceable water will be prin-
cipally taken into account; that is, the quantity of water over and above 10"/o.

In studying the laws of water circulation and the role played therein
by the roots the following consideration must not be lost sight of.
Uoung soots hold so much water (80" o and more) that their growth is
only possible where there is liquid water, and the more frequently the
tips of the rootlets meet with water drops in the soil, the more normal
will be the growth of the root. Therefore the ideal surroundings for roots
are those where all the interstices between the hard particles whether
of soil, chaircoal or other matter, are replete wixh water. Then the root-
covers will meet with no difficulty at any point in obtaining water and
the grov/th of the root will be continuous.

Now suppose that the interstices of the soil are not all filled with
water, but that some contain air, as stated above. The more frequently
such vacuities are met with the more difficult will be the growth of the
root; and it may happen that the d'stance separating the drops of water
is too great for the growing tips of rootlets to traverse, without the aid
of the requisite water on the way. Developement in the growth of the root
will cease; and if many roots of the same plant happen to be in such a
dry vicinity their developement as well as that of the whole plant will
cease or the growth may proceed more slowly if the rest of the roots
find water. And the oftener any part of the roots of a plant finds water,
the better will be the developement. For that reason the whole root- system
of a separate plant may show a far from equal developement in all its
parts. The hydrotropism of roots (fig. 6) is met with on our dry steppe
soils in a very severe form.

All the stages of this process may be found in the same soil: part
of the roots may find themselves in an horizon saturated with water;
further on, air gaps may be met v/ith at intervals; then, more frequently,
but small in extent and mterrupted, spaces filled with water drops; then
only a few drops of water dispersed simply or several together, in a
fairly large area of soil; and lastly we find no drops of water at all in
the soil but only that which has adhered to the upper surface of the soil
particles in the shape of an extremely thin layer. In the last instance
we have useless water; for when the tip of a rootlet comes into contact

— 27 —

w

ith it, the rootlet itself is so replete with water, and the area of contact
between rootlet and the soil particles is so small, that the water cannot be
imbibed. If the air between the soil particles becomes ever dryer the water
adhering to them will evaporate and leave the soil bone dry. In arid steppe
country, both the soil and the plants grown thereon suffer every year
from all the above mentioned stages regarding conditions of moisture.
All these inter-relations between humidity of the soil and plants are sup-
ported by facts in the following statements; where, out of numerous sta-
tistics at my disposal. I shall only cite those observations relating to the
yearly soil water regime of fields sown with barley, winter wheat, maize,
and potatoes, on waste land, pasture, etc.

V. The yearly water regime in the root-inhabited layers

of the soil.

The root-inhabited layer, taking into consideration the depth penet-
rated by the root-system, is for certain plants like potatoes and flax equal
approximately to 2'/:^ feet (70 to 80 cm.) For others like sunflower and
beet-root about 4'/-2 feet (150 cm.). But for the majority of cereals it is
about 31/2 feet ( 100 — 120 cm.). On the Odessa experiment field, experiment
fixed the soil layer at 7 feet (200 cm.), that is, the horizon lying deeper
than the root-inhabited layer was also investigated.

The observations showed that the root layer became more humid or
got dryer according to the time of year and the quantity of atmospheric
deposit. I call it the periodically humid layer. Under it, to a depth of
160 to 180 cm. is fonnd a layer which is almost constantly in a dry
condition — or only contains useless water — and which I call the interme-
diate dry layer. And finally, under this layer, begining from a depth of
160 to 180 cm. lies the permanent humid layer, containing 2 to 3" 0 in
the upper and 7 to 8"/() in the lower horizon, of useful water and exten-
ding to the ground water.

When the intermediate dry layer moistens and the soil becomes
moist from the surface to the ground -water we get an uninterrupted
moist layer.

The diagrams illustrating the yearly course of soil humidity have
been drawn up from tables, printed in the reports of the Odessa expe-
riment field")

••) In all the following diagrams the unshaded parts denote dry soil wit-
hout any serviceable water, but with about lO'-'/o of useless water. Soil con-
taining 1 to 20/0 of serviceable water is shaded a light grey colour, and 2 to
7'\'u dark grey. In general the presence of useful water is shown on the dia-
grams by grey shading of various depths; the more water, the darker the shade.
There are also several blended deviations from the normal course, arising out
of some accidental feature of the spot from which the soil sample was taken.

29 —

The periodically or upper humid layer.

Many years observation of soil humidity on the Obessa Experiment
field, permit the following principle deductions to be made.

Every year, at the end of June or the begineni^ of July — and with
a dry spring season at the end of may — our cereal grasses consume all
the reserve water which has accumulated in the whole thicl^ness of the
root-inhabited layer (110 — 150 cm.) during autumn, winter and spring;
that is to say, that towards autumn no useful water remains in reserve
for the following year or for the subsequent culfvated plants, when grasses
have been grown on the soil. The submitted diagrams (10, 11, 12 and
13) show this clearly. Thus diagram 10 shows the early course of soil-
moisture sown with barley (in 1905). The accumulation of water in the
superficial layer commenced from november of the previous (1904) year.
By winter the thickness of the humid layer had attained 35 c. m. and
remained so the whole winter because the whole layer froze and the
water was in a rigid condition and consequently could not shift its posi-
tion. After the frost, from the end of march until the end of april the
water sunk downwards about 10 c. m. and the layer attained a thickness
of 45 cm. which constituted almost a third of the soil-layer neccessary for
the normal developement of the root-system of barley. As we know, from what
has been already said about the developement of root-systems, the roots
of barley reach a depth of 50 cm. 31 days after sprouting; and as the
barley was sown in 1905 at the begin-ng of march, its roots had already
penetrated the whole humid layer by the end of april. Notwithstanding,
the growth of the roots ceased at a depth of 45 c m., or a little deeper,
because the root-tips theu reached a dry layer void of serviceable water.
To make up for this, the barley increased the developement oi its lateral roots in
the upper and more humid layer. The increase in the quantity of roots is such
an insignificant soil layer as 50 cm., instead of a normal 110, must have
involved an increased expediture of water in the humid layer. In fact, by
the middle of may the reserve of useful water was exhausted neither a
light nor a dark grey shading is to be seen in the periodically humid
layer. The plants must have perished in the absence of rain but during,
the period of vegetation (81 days) there were 39 falls of rain giving 68,4 m.m.,
out of which there were 6 useful ones of from 5 to 10 m.m. With a
sufficiently thick humid layer and such a plentiful supply of watery
deposit there should have been a good crop; but the thinness of the hu-
mid layer produced another effect; — the crop barely ripened by reaping
time (2-nd June) and was very poor -about 30 puds (98 s-t). Palpably
the thickness of the humid layer in spring at seed time is of final impo-
rtance, if there is not plentiful rain later on. And so by the middle of may

0^-

in

808 o 800 qoQq Q 00 qo 0000

I I

o

^-

3-"

?3

>

=s

3

>

CO

C3

":>,

'-/I

OO OnOOOOo RnOO O OOOQo^

XGOOoOOOQOqOO o q O O O O Q

0^-

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0^

^

■n

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m ro

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^

oono^ooogooooooogo^

— 30 —

the soil was denuded of all lis reserve oj water in the root-inliahitahle
layer.

There were also other cases analogous to the above (see fig. 11. 12, 13).
The downward movement of the water (fig. 11) did not cease from
October to april, because the soil was not frozen up during winter dee-
per than 40 cm., and water confined to percolate into the layers deeper
than 40 cm. up to april. But by that month the roots of the barley sown
on the 25-th of february 1906, had already penetrated to such a depth
that they took up even the lowest horizon of the humid layer and the
percolation of water into deeper layers ceased by the end of June; r/;7r/ <-//
the period of reaping all the reserve water in the root layer was expeuded.

In the next instance (fig. 12) we have to deal with wild instead of
cultivated plants - intermediate (June) green fallow in 1905. Here also the
accumulation of water, or, which is the same thing, the thickness of the
humid layer commenced in the previous autumn of 1904. During win-
ter the condition of the humid layer remained unchanged owing to the
whole layer freezing up and the water becoming solid and immovable.
Although the lowest horizon of the humid layer reached a depth of 100
cm. in may 1906 (fig. 11) and only reached 45 cm. in april 1905,
nevertheless, in both cases, no surplus of serviceable water remained, at
the begining of July. In both cases (fig. 11 and 12) the water was consu-
med by cultivated and wild plants. It is evident therefore that as regards
the consumption of water there is no difference between wild and culti-
vated plants. By midsummer all the reserve of serviceable water in the
root layer is utterly exhausted.

It is not only spring growths that entirely consume the whole of the
useful water by the end of the period of vegetation. The same is observed
in the case of winter growths. In iig. 13 the state of humidity is depic-
ted on fields sown with winter wheat following a crop of barley (rota-
tive culture) and after black fallow (fig. 14). In both of these cases the
reserve water in the root layer is expended by reaping time.

Maize (f'g. 15) impoverishes the reserve useful water somewhat la-
ter that grasses — not before august.

Potatoes (fig. 16) and flaxx stand out quite separately from all cul-
tivated annuals at least from those investigated by me. As short-rooted
plants, they do not require a deep layer, and from 1 to 2"/o ol useful water
remains in the soil after their maturity in august.

On diagram 17 the yearly course of humdity in the soil of waste
land in shown as observed from year to year. Usually the humid layer
here, in spring, is not thicker that 40 or 50 cm. and often about 30
cm. Towards midsummer it gives up all its useful water to the roots the-
rein and then remains dry until autumn. But what is particularly inte-

x;

.>.

OnOOOOogoOOOO

Q o Q. o o

Oyc6^ioco-t-coo5Q = CN!C2^iocDr^gg

00 91 O

CM

qO oooooooOcoo

':::h

S5

-vi O) CJi -^ CO to —
O O O C O O O

>

— 31 —

resting is th's: that below the humid layer on old ploughed soil lies as
we saw before, a dry layer, which however contains about 10" ,, of wa-
ter (useless). But on waste land th's dry layer (show on the diagrams
by vertical lines) has only 6 to 8" ,, that s to say it 's much poorer
in water than the old plougled fields. Comparing the two cases— the
course of humidity on oldploughed and waste land — we see that in the
former case the humid layer is thicker and the underlying dry layer
holds more water. Consquently, the yearly balance of water in root-inha-
bitable layers of waste-land is undoubtedly less than in old ploughed soil,
and that is the defective side of leaving fields to lie fallow, as a remedy
against drought. For th's old-fashined point of view is diametrically
opposed to the truth. The tillage of virgin steppe does not encourage
drought, but minimizes it, changing waste land into old ploughed land
with its larger yearly balance of water. Therefore // must be admitted
that allowing afield to lie waste /or seueral years is injurious to irrigation.

The /jermanent humid soil layer or lower humid layer.

On old ploughed fields (fig. 10 and others) at a depth of 160 to
180 cm. (4' ■_' to 5' -j feet) the permanent humid layer commences, which
holds a certa'n quantity of useful water — about 1,2 or 3"',, — all the year
round. It extends without interruption, to the ground water, on our step-
pes to 140 or 175 feet. On waste land the permanent humid layer lies
far deeper than on old ploughed land about 14 to 30 feet. The perma
nent humid layer on old ploughed land is shown at the botton of the
diagrams by grey shading, but on waste land it is not noticed even at
a depth of 240 cm. — This simple fact — the layer lying at several fathoms
on waste land and at a few feet on old ploughed land shows that the
depth where the permanent humid layer lies is not constant; and the
more the farmer endeavous to accumulate water in the soil, not by let-
fng the land lie idle, but by its culture, the nearer, the permanent hu-
mid layer will get to the surface.

7y:e intermediate dry layer ■■).

Between the upper humid layer of soil, periodically moistened by
atmospheric residue on the surface, and the lower permanent humid

*) H. N. Visotzkii calls this layer „The dead horizon of dryness", but we
cannot agree to this title, for, as we shall see later, one year under black fal-
low would make the soil „alive" and habitable for plant roots. The role of the
intermediate dry layer is only mentioned by H. N. Visotskii as iar as it con-
cerns forest growths.

— 32 —

layer, lies the intermediate dry layer, containing only about 10"/,, of use-
less water which is not shown on the diagrams. If the upper humid
belts have not got into the proper condition requ'red of a normal root-
inhabiting layer (110 to 140 cm.) the roots developing therein always
meet with an insurmountable barrier, the intermediate dry layer; for they
cannot penetrate into this dry sphere void of useful water.

We saw above that the most essential factor for a good crop ofan-
nual plants, whose root-systems do not reach so very deep (100 to
150 cm.) is the thickness of the humid superficial layer. Perennials-
clover, shrubs, trees— differ is that respect. Their root-system must
penetrate several fathoms deep in order to enable the plant to develope
normally.

If the intermediate dry layer is injurious to cultivated annuals, pre-
venting full developement of the under ground parts when the upper
humid layer is less than the root-inhabited layer and the root-system,
cannot develope normally, then the effect of the intermediate layer on
perennials is to exclude every possibility of their culture. Annuals may
develope luxuriously if their root-inhabited soil layer (to 150 cm.) is
mo'st. Per ennials, which develope their root-systems during many
years, extending them for several fathoms, must have moist soil in the
whole of the depths they penetrate. And if they meet an intermediate
dry layer in consequence of which their roots (the upper lateral roots
turn downwards after several months and do not differ in size from the
main roots) cease their growth, the lateral roots commence to increase
their developement. The humid layer gets crowded with a network of
side roots which rapidly consume the reserve of useful water and by au-
tumn the whole root-inhabited layer dries up-the plant neverthelless
continnes to vegetate weakly far into autumn.

In the following spring the strongly developing lateral roots com-
mence early to exhale large quantities of water and by the end of may
or the begining of June all the reserve water is expended. Thus the
plant, in the second year of its existence, has to live through the hottest
summer period, v/hen useful water is absolutely necessary owing to the
heightened process of evaporation, in soil which has become dried up.
Usually the plant cannot outlive this period and perishes.

The systematic failures experiences in cultivating perennial edible
herbs and trees in dry steppe places can only be explained thus; that
these plants are treated under conditions only suitable to annual plants.

A perennial plant cannot satisfy itself with the upper humid layer
above; it must be able to stretch out its roots into the lower permanent
humid layer which, uninterrupted by dry belts capable of arresting the farther
downward progress of roots, extends to a depth sufficient for the roots of

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perennial plants. However between the periodically upper and the per-
manent lower humid layers, there usually lies the separating intermediate
dry layer. And in order that the roots of Perennials may reach the per-
manent moist layer, the intermediate dry layer should not be there, or
it should be also moist. Therefore l/ic norma/ cotulilion of existence for
perennials require that there should be a humid layer at their disposal as
deep as the whole leni^th of their root-system.

The permanent humid layer.

There is but one way of getting sid of the intermediate dry layer
or, which comes to the same thing, of moistening it; and that is by lea-
ving the field in clear black fallow. On fig. 18 the course of humidity
on black fallow is shown.

Here the accumulation of water 'n the upper layer also commences
in autumn, as it generally does on all fields under wild or cultured plants.
From spring onwards the soil water percolates deeper and deeper until,
by auntumn, the period of sowing winter corn, the thickness of the upper
humid layer may become so great that the intermediate dry layer gets
humid through, upper and lower humid layers meeting and running
together. In that case the soil will contain a certain quantity of good
water, from the surface to the ground-water, and we get an uninterrupted
humid layer (fig. 18 — in September).

In such a continuous layer, roots of perennial plants will find good
trxkling water in all its depth, which it will be able to penetrate whet-
her it be 3 or 70 feet.

But it may happen that the water accumulated under black fallow
does not sink into the lower permanent humid layer during the first year
and that there still remain the intermediate dry layer between the humid
ones. With an average years precipitation the upper humid layer will
not be less than 100 cm. (3' •_> feet) and the lower one will commence
from a depth of 160 — 180 cm. as we said before. Therefore the dry
layer remains towards winter about 60 to 80 cm. During the winter the
water will percolate deeper even in a certain depth of the upper humid
layer freezes. If the percolation goes on only at the minimum rate —
10 cm. per month the upper layer will reach the lower one in the
course of the winter and towards the beginning of spring will form a con-
tinuous humid layer. In very moist years, which to tell the truth, are
comparatively rare here, the atmospheric residue does not accumulate in
large quantities in a thick layer of soil, but soaks though a very thick
layer of 130 to 150 cm. In such a year the soil find's itself in the same
state of saturation as it does under black fallow.

— 34 —

Therefore the role played by black-fallow in dry steppe localities
is of the highest importance, because it is only by its application that
deeper soil horizons, even those inaccessible to the roots of perennial
plants, can be made moist.

These horizons inaccessible to annuals having received water, hold
it and form a permanent humid layer. Than water sinks deeper than the
root-inhabitable layer in wet years, whatever plants are under cultivation;
and it does the same in average years as regard moisture, when certain
plants like potatoes and flax are cultivated. This surplus of useful water
percolating beyond the limit of the root-inhabited layer goes towards the
formation of a permanent humid layer.

VI. The appearances of drought.

Having become acquainted with the laws of water circulation in
soil under various technical modes of culture such as leaving fields in
clear black fallow, green June fallow, waste land, and then under culture
of various plants, we shall proceed to examine those concrete cases where
plants are exposed to drought, and must inevitably face its.

A temporary scarcity of water in the soil, affecting plants and hol-
ding back the normal course of their life processes, is what is known as
drought. But the scarcity of water in soil does not only depend upon a
small quantity of atmospheric residue (rain dew etc).

The farmer way lose many of the advantages of the falling residue --
principally in the form of rain-through bad management: the adoption
of an incorrect mode of tilling the soil when preparing it, for sowing or
when attending to plants, an unsuitable rotation of crops, one after anot-
her, and finally an irrational organisation of the whole farm.

We have already seen that leaving fields lying waste, gets injuri-
ously upon their state of moistness. By spring, only a small thickness of
layer is moistened, and the expediture of water increases from the begin-
ning of the vegetation period. Naturally the extremely compact surface
of waste fields prevents water from accumulating therein, for a conside-
rable portion of rain-water runs off the slopes and declivities. And it
must be remembered that the same quantity of rain falls on waste fields
as on the neighbouring ploughed ones.

It may be seen from the following figures, that insufficient advan-
tage taken of the falling residue, may have a great deal to do with the
appearance of drought. There falls in the sonthern governement of Russia
from 320 (the v/estern part on the Black Sea) to 400 mm. of residue per
year. If we exclude a third of this quantity (about 30" n) such as small
deposits which evaporate quickly from the soil, and certain fractions which
run off the surface without being absorbed we have still remaining not
less than 150 mm. which enters the soil and may be used by cultivated
plants. Bearing in mind that 1 mm. gives 650 poods ") of water to a dessiatin*")

") Pood=36,ll pounds.
^•^) Dessiatin^2,70 acres.

— 36 —

and that the development of one pood of dry mass of the crop in bulk —
straw and grain requires on an average about 400 poods of water
(according to Haberlandt about 375) for its growth then from every mil-
limetre of residues we should get 1 ' ^ poods of crop, and from 150 mm. —
about 225 poods. Spring cereal give twice as much straw as grain (ro-
ughly estimated, although barley give about equal quantities ot each)
therefore an average crop of 225 poods schould give 75 poods of grain.
Such schould be the average fertility of spring cereals in our southern
governements if the whole of the water entering the soil is taken advan-
tage of. Nevertheless, the average fertility according to statistics equals
about 40 poods. Evidently, the cultured plants do not get the benefit of
the whole of the water. As the height of the crop in our southern gover-
nements depends exclusively on the quantity of the water in the soil,
the deficiency in the harvest must be attributed to the farmers bad use
of the soil water which was at his disposal and of which he did not take
full advantage.

Let us see how the accumulation and expenditure of water goes
on under the various combination of farming — the various alternations or
rotations of crops.

We will take the simplest cases: a three-course rotation on bare
fallow, a four-course rotation and a free course of cereal cultures exclu-
sively. From these combinations many other rotations may be termed,
arranging them to pit in with the diagram of the yearly course of soil
humidity.

With a three-course rotation (fig. 19) — bare fallow, winter and
spring corn — the humid layer gets so moist during the fallow course,
that when the winter corn is sown its roots, which as we have already
seen in rye (130 cm.) are longer than spring corn, can develope to a
full normal length; for they do not meet the intermediate dry layer in
the whole of their expanse.

Such a large reserve of water in the soil after clean bare fallow"")
assures the winter crop even in a dry season ""'•).

After the bare fallow, the winter corn expends all the useful water
in a soil layer of 120 cm.; but below that horizon there is still a reserve
which sinks, by degrees, to the level of the permanent humid lower
layer, by the following winter.

"") For accumulating water, green april fallow stands as high as bare fal-
low, if ploughed, when possible, at that period when the weeds are just com-
mencing their development and have not touched the reserve water.

**) In 1899, when not a grain was gathered in a distance of 40 versts,
the Odessa experimental field produced 85 poods of winter wheat sown on
bare fallow.

— 37 —

The moment of this deep exhaustion of the humid layer by the
winter corn is the commencement of the formation oi the intermediate
dry layer. In the approching autumn, after the winter corn has been
cleared away, the periodical humid layer commences to form on the
surface: and in the winter preceding the sowing of spring corn we already
find all our three layers: the upper periodical humid (from the surface to
40 cm.) the intermediate dry (from 60 ••) to 180 cm ) and the perma-
nent humid layers (from 180 cm.--"') and deeper to the ground water).

Towards the time for sowing spring corn (barley) on fig. 10 the
state of humidity with barley is shown for 1905, a dry year — the thickness
of the humid layer was about 40 c m. We saw that the lenghth of ripe
barley roots equal 110 cm. It is obvious that with a thickness of the
humid layer of 40 c m., the root will only reach that depth and then
cease their growth, having met with an obstacle which they cannot pass,
in the shape of the intermediate dry layer. The life processes in the
growth of barley, suffer from such a shortening of the roots first of all,
in this respect: that instead of long main roots the side roots will com-
mence to develop strongly and there is not sufficient water for a fresh
quantity of roots. The plants, hav'ng formed a root-system shorter than
others and proved themselves to be in a horizon of the utmost dryness,
perish in various spates of development. Others, forcing their roots a littl
deeper give a v/eak crop of partly developed grain; and finally those
which reach the deep horizons before the others give a more or less
normal grain. In 1905 the crop was certainly very poor-about 30 poods,
comparatively ' :; of the normal, and the humid layer ot 40 c m. Was
also about ' .■•, of the normal thickness of the rootinhabitable layer for barley.

In moister years at the approach of the period for sowing spring
corn the thickness of the moistened soil layer fluctuates from 79 to 100
c m.; nevertheless, the v/ater entering the soil from the autumn, winter
and spring deposits, are insufficient to moisten the intermediate dry layer.

Therefore, with threecourse bare fallow rotations, a part of the useful
water accumulated durind fallow remains unused by the winter grasses
sinks into deeper soil horizons and makes up the loss of water in the
permanent humid layer. Obviously, the oftener the field is put under fallow
the nearer the permanent humid layer will approach the surface with
every years fallow, and the thinner and thinner the intermediate dry
layer will become.

e

") Between 40 and 60 cm. lies the changing layer from humid to dry,
holding l"'u and not more than 2" u of useful water-shaded a light grey tone.

■•■■) Above it lies also the changeable layer, holding as much water as
the upper one-shaded a light grey tone also.

— 38 —

With four-course rotation (fig. 20) — bare fallow, winter corn, potatoes
(thorough ploughed plant) and sprind corn the distribution of water will
be different than with the three -course rotation which we have just
examined.

In the fallow and the following winter-corn stages the distribution
of water, that is its accumulation and expenditure, will be similar to that
which we saw in the threecourse rotation. Exactly in the same way, after
the reaping of the winter wheat the upper humid layer appears with the
intermediate dry layer below it; and still lower-- the permanent humid
layer. But in four -course rotation potatoes follow the winter corn, not,
spr'ng corn. Potatoes (fig. 16) do not use up all the reserve water
(5 to 7^';'ii). There still remains 1, 2 or 3" n in the soU (on fig. 16 shown
from august by a I'ghter grey shade) after the harvest. This remaining
unused water forms that fund which guarantees the crop of spring corn
following the potatoe crop. Other thorough ploughed peants like melons
and flax leave the field in about the same condition of humidity. Maize
does not leave any serviceable water in the soil and in this respect is
exactly like other cereals.

In this manner thorough ploughed plants give the spring growths
which follow them a clean field cleared of weeds, and leave the fields
in various conditions as regards soil water, and potatoes leave it in the
very best condition. And what is more: popatoes must be reckoned the
best predecessors of both winter and spring corns. Alm.ost as good in
that respect is flax. Under it the field gets free comparatively early, in
June, even earlier than when under potatoes. Then the root- system of
flax penetrates to a less depth than grass cereals and leaves a certain
water reserve.

After potatoes follow spring corn in a four-course rotation. Having
received, besides the remains left from the culture of potatoes, several
driblets of useful water from the autumn winter and spring deposits, the
spring culture towards harved use up all the reserve water and leave
the root layer of the soil in a dry state, with only useless water, until
the autumn months when the formation of an upper humid layer commen-
ces (on fig. 20 from September).

With tree-course rotations in the fallow stage, and with four-course
in the fallow and after potatoes, useful water remains a long time in
contact with the particles of soil in deep horizons of 80 cm. and deeper.
During this period processes of a chemical character go on energetically
through the whole thickness of the humid layer; and partly, in the su-
perficial layer, of a biological and bacteriological character. Mineral mat-
ter is transformed in entering, by ass'milation, the roots of plants. After
bare fallow and potatoes the process of transforming mineral matter into

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— 39 —

a soluble condit'on continues throughout the winter. Undoubtedly, besides
accumulating water, these methods of culture also enricher the water
so'l solution with mineral matter, and raises the potential of the crop of
that plant wh'ch will be sown on such a field.

The distribution of water in the soil assumes an entirely different
complexion under a permanent culture of corn (fig. 21).

This farming method -the absense of rotation is adopted in sou-
thern Newrussian governments. On our illustration the series of cereals
are- winter wheat, barley, barley. There may be other combination
spring wheat, barley, winter wheat, barley, winter wheat and so on. The
order of succession is here indifferent; it is only important that neither
fallow nor thorough ploughed plants take any place in such farming, and
our local thourough ploughed culture — maize — as we have seen, uses up,
by harvest time, all the reserve useful water in the root layer.

Every year the formation of the upper periodically humid layer
commences from autumn, generally in October, and by the time the
plants sown therein are ready for reaping, it has become dry, only use-
less water remaining. The distribution of water may be thus depicted.
From the surface to the lower permanent humid layer, which, under such
conditions cf culture, often lies deeper than on old ploughed land (160
to 180 cm.), the soil layer remains dry for many years, and only in the
superficial parts, from late autumn even from december to July, that is
during seven or eight month, moisture appears in a soil layer of 40 to
50 cm. In very moist years, like that shown on fig. 21, 3-rd year, it
reaches 10 cm. and more. After such an unusually moist year a part of
the useful water in the lower parts of the periodically humid layer may
not be expended; then it comes in for swelling the reserve useful wa-
ter in the permanent humid layer, as may be seen on fig. 21, 1-st year,
usually upper humid layer is, in spring not thicker than 40 to 50 cm.
It is moist for 7 or 8 months in the year. During that time, the proces-
ses of transforming mineral matter into solution, and the preparation of
food for the coming sowing, goes on therein. But as regard the soil
layer from 40 to 50 cm. to a depth of 160 to 180 cm., // may remain
in a dry state for many years with only useless water, and processes of
a chemical character will he either absent or proceed on an insii^nificant
scale; and no transformation of mineral salts into solution may take place.

The soil gets impoverished through lying in dry state for a long
time, because more water is required to turn the quantity of mineral
salts necessary to the plants into solution than in rich soils, where mine-
ral matter is found in a soluble condition, ready for use. And the longer
his dried up layer of soil is without a supply of atmospheric water, the

— 39 —

a soluble condit'on continues throughout the winter. Undoubtedly, besides
accumulating water, these methods of culture also enricher the water
so'l solution with mineral matter, and raises the potential of the crop of
that plant wh'ch will be sown on such a field.

The distribution of water in the soil assumes an entirely different
complexion under a permanent culture of corn (fig. 21).

This farming method the absense of rotation is adopted in sou-
thern Newrussian governments. On our illustration the series of cereals
are — winter wheat, barley, barley. There may be other combination
spring wheat, barley, winter wheat, barley, winter wheat and so on. The
order of succession is here indifferent; it is only important that neither
fallow nor thorough ploughed plants take any place in such farming, and
our local thourough ploughed culture — maize — as we have seen, uses up,
by harvest time, all the reserve useful water in the root layer.

Every year the formation of the upper periodically humid layer
commences from autumn, generally in October, and by the time the
plants sown therein are ready for reaping, it has become dry, only use-
less water remaining. The distribution of water may be thus depicted.
From the surface to the lower permanent humid layer, which, under such
conditions cf culture, often lies deeper than on old ploughed land (160
to 180 cm.), the soil layer remains dry for many years, and only in the
superficial parts, from late autumn even from december to July, that is
during seven or eight month, moisture appears in a soil layer of 40 to
50 cm. In very moist years, like that shown on fig. 21, 3-rd year, it
reaches 10 cm. and more. After such an unusually moist year a part of
the useful water in the lower parts of the periodically humid layer may
not be expended; then it comes in for swelling the reserve useful wa-
ter in the permanent humid layer, as may be seen on fig. 21, 1-st year,
usually upper humid layer is, in spring not thicker than 40 to 50 cm.
It is moist for 7 or 8 months in the year. During that time, the proces-
ses of transforming mineral matter into solution, and the preparation of
food for the coming sowing, goes on therein. But as regard the soil
layer from 40 to 50 cm. to a depth of 160 to 180 cm., // may remain
in a dry state for many years with only useless water, and processes of
a chemical character will be either absent or proceed on an insignificant
scale; and no transformation of mineral salts into solution may take place.

The soil gets impoverished through lying in dry state for a long
time, because more water is required to turn the quantity of mineral
salts necessary to the plants into solution than in rich soils, where mine-
ral matter is found in a soluble condition, ready for use. And the longer
his dried up layer of soil is without a supply of atmospheric water, the

— 40 —

less soluble mineral matter there will be therein, and the more impove-
rished the soil will become.

In this manner an uninterruplcd culture of cereals br/n,s;s about,
as an unfailing consequence, an intense, systematic drying up of tiie lower
lialf of tJie soil layer inJiabited by tlie roots of cereal grasses (the depth
of the layer inhabited by them equals 110 to 130 cm. but only 50 or
70 c. m. moistens yearly at the best of times) and an almost complete
cessation tiierein of the cliemical transformation of mineral salts into a
soluble condition, or, which is the same thing, a systematic impove-
risfiment there of.

These chronic absense of useful water in an important part ot the
root-inhabited layer, explains the „ poorness" of the peasants fields. If these
fields sometimes, exclusively in moist years, receive water enough to
moisten the whole root layer, that water dissolves but an insignificant
unnormally small quantity of mineral salts; and in order to assimilate
and use them in building up their tissues, the plant must expend all the
water; that is to say, that from a large guantity of water a small quan-
tity of mineral salts is extracted. Obviously the abundance of soil water
does not go to the benefit of the plant in this case; it must exhale water
energetically, its cells hold too much water, the stalks become spongy,
easy to break, and high coloured.

In this way one very moist year amongst a whole row, not of dry,
but even of average moist years, guarantees the crop: but that crop will
be far lower than it might have been, had the mineral matter been in a
higher state of solubility through the presence of water in the root layer
during the preceding years.

Have looked into the distribution of water in three-course, on bare
fallow, and four-course rotations and then in uninterrupted culture, we see
that in a three - course rotation, when spring corn is sown after winter
corn, we get a condition favourable to the appearance of drought. On the
removal of the winter corn, the whole root layer turns out to be dry, and
the whole future of the barley crop depends exclusively on the autumn
winter and spring deposits. If they happen to be sufficient we can rely
upon an harvest; but if they chould be small the layer only moistens to
30 or 40 c. m. and there can be no hopes of a good harvest even with
a decent quantity of deposit like that of 1906 (page 29). Only an uncom-
monly moist spring, which so rarely happens in southern black -earth
districts, can raise the crop above the average.

In a four-course rotation winter corn is followed by potatoes, the
root layer for which is not great. Therefore an important thickness of
humid layer is not requisite to guarantee the crop. Here, a complete
faillure cannot be expected, and even a moderately moist spring guaran-

— 41 —

tees the crop of potatoes. Then, after potatoes, a certain reserve of useful
water remains in the soil for the next spring corn, and with a moderately
moist spring the crop of barley is guaranteed by a small reserve of wa-
ter, and a clean soil, after the culture of potatoes. Therefore in a four-
course rotation, there is no moment in the culture which could create in
the root layer a condition favourable to the appearance of drought.

With an unbroken culture of cereals every year, the reserve of
useful water is entirely used up at the period of reaping, and every
year the farmer finds himself threatened with drought. Practice confirms
the instabilety of farms built up on an uninterrupted culture of cereal
grasses solely. There must be a change of culture, but not restricted to
changing one cereal grass by another, as barley by wheat. The root-
systems of cereal grasses are nearly alike, and so are the limits in
which they can make use of serviceable water. In a change of culture
one must reckon, not so much with, the varieties of the parts about gro-
und, as with the varieties in the dimensions and structure of their root-
systems. Maize and barley differ greatly in their above ground features,
but they both dry up the root layer, towards the reaping period, completely.

The chain of seed changes or rotation should be made with the
idea of root changes. Song rooted plants should alternate with short-rooted
and dence rooted (with a thik network of small roots) with meagre-rooted
(with a open network). In our four-course rotation after long rooted (win-
ter wheat or rye) follows short-rooted (potatoes). Then again long - rooted
(barley, oats). If after spring corn, we place thorough ploughed short and
meagre-rooted (flax) and after that agaitn long-rooted (spring grasses) we
get a six-course rotation probably the most perfect for southern steppe
black-earth of a lightish type. And so, the cause of drought is not con-
fined only to the fall of a small quant'ty of atmospherie water. The cause
of drought is more complex and is rooted pre-eminently in the incorrect
technical methods of farming-late turning up of the fallow in spring (June
fallow fig. 12), in an incorrect organisation of crop rotation and in the
system of letting land I'e untouched. The farmer himself prepare the way
for drought in the course of a whole series of years by failing to look
after the accumulation of water in the root layer of the soil and by the
way the increase in the quantity of soluble matter. Our blackearth soil,
on condition that a certain reserve of useful water is left in the root-layer
as, often as possible, gives a prolific harvest, in a year with a less than
average quantity of falling deposit; for the water which enters the soil
finds there a sufficient reserve of dissolved mineral salts; and the plants
in order to assimilate it and use it in building up their cells expend less
soil water than they would from impoverished soil, in getting the same
quantity of mineral salts.

— 42 —

The presence of drought is brought about as follows. Towards the
advent of spring the field becomes covered with weeds which appear
here after the cultured plants are cleared away. These weeds absorb the
whole of the insignificant remainder of useful water, held in the small
interstices of the soil particles in the form of small drops, which the more
exacting cultured plants could not use. The soil on such a field turns
out to be dry to a depth of 41/2 feet or more. Autumn, winter and
spring (the non-vegetation period) contributes so little water to the soil,
that at the period of spring sowing only the superficial soil layer becomes
moistered to 40 or 50 cm. The roots of the cultured plants rapidly pe-
netrate the whole of this layer with a dense network, and, meeting fur-
ther with an insurmontable barrier in the shape of the intermediate dry
layer, cease their downward growth, and give out a much more than
normal number ot side roots, which expend the reserve useful water in
a shorter time than a normal number would. In consequence of the fai-
lure of water in the soil the weaker plants commence to perish, and the
more hardy become prematurely ripe having reached the deeper horizons
of the humid so 1 layer with their root-systems.

The intermediate dry layer, lying under the upper periodically humid
layer, does not contain sufficient useful water, and the mineral salts the-
rein remain in an insoluble condition. When a favourable moist spring
arrives and the dry layer moistens, the plants use up in assimilating
mineral salts alone, much more useful water than they would on rich
soils where the mineral salts are already dissolved.

Consequently drought is preceded by two factors:

1) A part only of the root - inhabited soil layer being in a moist
condition at the period of spring sowing, instead of the v/hole layer of
110 to 130 cm.

2) A chronic perennial dryness of the intermediate dry so.l layer
lying under the periodically humid layer; and as a result of their dry-
ness, the absense therein of the chemical processes for transforming
insoluble mineral matter into soluble and

3) A deep position of the permanent humid layer owing to which,
the intermediate dry layer is of very great thickness.

VII. Measures for contending against drought.

Having become more acquainted with the primary causes of
drougt, we can with greater facility decide upon the means of contending
with it, because in doing so, quite definite aims must be put forward. The
first and most important aim is to increase the upper periodically hu-
mid soil layer. Tnis may be attained by the accumulation of water,
careful nursing of that already accumulated, and an economical outlay of it.

The only water that can accumulate in the soil is that which en-
ters ,t from the atmosphere. Consequently the farmer should see to it
that all the water falling on the field is absorbed by the soil and that
none of it from any reason whatever, runs off the surface; and that it
percolates into the superficial layer as quickly as possible. A spongy
ploughed surface on the field fully favours these conditions, and the fur-
rows should run across the declivities, if there are any.

Attention to the accumulate of water should be given immediately
after the crop in got in. The thing is that in July after reaping finishes
there is heavy rain for a more cr less short time all over the southern
steppe governments in certain years the most copious of all the spring
and summer rainfalls. If the iield is scaled after reaping, even to the
small depth cf 3 or 5 inches, all the water will be absorbed by the soil
and will serve as a pledge for the futur crop.

On unploughed fields a considerable part runs off the slopes, and
is lost. Our farmers treat this summer rain with criminal carelessness.
It appears to them neither beneficial nor welcome, as it interferies with
the threathing of the corn.

Nevertheless there falls (on the Odessa experiment field), on an
average for twelve years, about 45 m. m. If about 30"() of th's is lost
through evaporation, as we mentioned above, still, for all that, about 30
m. m. may be held by the soil for the future crop, or, reckoning 1' ■_>
poods to each millimetre, an addition of 45 poods will be guaranteed to
the crop, giving about 15 poods of grain. This calculation must however
be regarded as underestimated because the water which enters in the
soil, will increase the change of mineral matter into a dissolved condition

— 44 —

during the 2 or 3 summer months. It is only necessary to harrow the
scaled field after the rain.

In the Newrussian governments it is the custom to sow winter corn,
without previously preparing the field, after the first rain at the end of
august or during September. It is the custom also for that corn to give
a weak crop, because the roots of the growing plant quickly reaches the
limit of the humid layer, under which lies the dry layer, and their
growth is arrested untM the next horizon moistens, which may not happen
until autumn is well advanced. Winter corn may be sown on scaled
ground without any great risk, if the humid layer equals 50 or 60 c. m.;
but, as we saw before, such a humid layer is absolutely necessary in
order that the winter corn may bush by the advent of winter"").

The field having been scaled soon after clearing up the cereal grasses,
requiring looking after; that is, harrowing after rain and repeated scaling
or turning over whilst weeds are growing. But whoever wishes to have a
cultured field must concern himself with the renewal of the reserve water
therein, immediately it has been spent; and the sole means of doing this
is to scale off the stubble immediately after reaping, between the unbourd
heaps of corn. In preserving water in the soil, by scaling stubble off the
field, and by subsequent tillage far into the autumu, the farmer rids his
field of large quantities of weeds and destroys their seeds. The autumn
weeds, which develope so riotously in certain years, exhaust the whole
of the atmospheric water whish enters the soil after the reaping of
the crop.

By the term ^economical expenditure" of soil water should be
understood a condition preventing a simple drop of water from being
wasted on the growths of weeds, which the farmer must, by all means^
destroy. But of course it is more profitable to destroy them while they
have not yet used up the priceless water which cultured plants must
have without fail, and before they have run to seed. This is the ideal to
which the farmer should constantly strive to attain. Therefore the field,
having been scaled after the harvest, must receive the same attention
as it wauld do under culture; then the sown field should be occupied
exclysively by cultured plants, and all the processes of their cultivation
thourough ploughing, hoeind etc) should facilitate the destruction of weeds.
For that reason fallow land should be ploughed in autumn or as early
as possible in spring, before the weeds have yet touched the reserve of
useful water.

") Cereal grasses bush when their root system reaches a depth of 50 c. m.
(25 inches).

45 —

The farmer should always remember, that every of dry weeds take
away 400 to 500 poods of water from his fields- that the root-systems of
wild plants develope more rapidly than those of cultured plants; and
therefore with simultaneous sprouting, the moister soil horizons will be
seized upon the roots of wild plants — and finally that wild plants can
absorb from the soil those minute drops left from the reserve useful
water, which cultured plants cannot make use of. He should not forget
Ihal the bitterest enemy of his field eulture and the liest friend oj drought
are the weeds on his field, which by attracting the reserve water left
after cultivated plants and by using all the atmospheric water entering
the soil in summer and autumn, prepare the way for drought. By ne-
glecting his cleaned up field right away to winter and by giving it over
to the disposal of weeds, the farmer himself takes a part in creating
conditions favourable to drought. In fixing the greatest loss to the farmer,
through weeds, at an extent equal to the crop, I do not exaggerate; the
loss is undoubtedly far greater.

The second aim for successfully contending against drought should
be the transformation of the greatest possible quantity of insoluble mine-
ral constituents of the soil into a dissolved condition and that is only
possible when the root-inhabited soil layer holds permanently, as far as
possible, a certain, even a small reserve of water which will aid the
chemical processes.

We know that cereal grasses expend all the reserve water in the
root-inhabited soil layer, even if that reserve be as large as it is on the
field after bare fallow (fig. 18). On the other hand, we know that certain
thourough ploughed plants like potatoes, flax and pumpkins do not use
up all the reserve water in their root layer. Therefore the organization
of the form or in other words the roration of crops, should not de confi-
ned exclusively to grain or cereal grasses. It is necessary that one crop
should succeed another in the rotation in such a manner that one year
of intense expenditure of useful water should be succeded by an year
when water, even if only a small quantity, is accumulated. From this
is derived the main principle of rotation for our black soil steppe districts-
after grass a thourough ploughed plant must be sown, but on no aceount
a grass. The simplest of such rotations will be two-coursed: 1) a cereal
grass, 2) a thourough ploughed plant. But a combination such as 2, 3, 4,
and so on, may be taken, and we get from six and eight course rotations.
If we add to our four-course rotation (fig. 30) another thourough
ploughed growth and a grass we shall probably get the very best rotation
for steppe black soil: 1) bare -fallow 2) winter wheat 3) partly - potatoes
and partly beatroot, 4) barley or sprind wheat 5) flax or pumpkins, 6)
barley, or oats. Such a rotation besides quaranteeing a fine c re f < .

— 46 —

cereal grasses, gives the farm sufficient fodder for his cattle. Here I shall
take the opportunity of saying a few words about the sowing of grass.
Grass cannot be included in the rotations and for this reason. Perrenial
green fodder has a very long root-system even extending to several
fathoms. All that thickness of soil must hold useful water, otherwise the
roots will not develope. Meanwhile in our soil at a depth of about 3'/2
to 4' 'J feet the intermediate dry layer commences, about 2','-.' to 3' ■.> feet
thick which stops the developement of the roots profoundly. And the only
v.'ay of distinging the immediate dry layer is to moisten it that is to
leave the field under bare fallow (fig. 18). Therefore the only method
which will guarantee success in cultivating perennial green fodder in
places with a small quantity of atmospheric deposit, is to sow it on bare
fallow. The most suitable fodder for the extreme south must be reckoned
lucerne and for the more northerly esparcet. In culture of green fodder
all depends upon the quantity of water held in the deeper soil horizons
accessible to roots in the 2-nd, 3-rd and subsequent years, and this
circumstance shows, how many years the fodder will keep preserving
the farming thickness of grass when standing. In favourable conditions
lucerne can remain on one place 5 or 6 years. On the Odessa experi-
ment field there were occasions when it remained 9 years giving in the
first four year 1 or 2 mowings of hay and in the last five years-yearly
mowings for grain and, if when it was possible also for hay.

In view of all these considerations, perennial grass cannot be in-
cluded in rotations. It is more practical to sow it on field part outside
the rotation, which at any moment when the grass begins to thin out,
may be used for rotation and a new area can be put under grass.

An increase of fodder matter in farm is undoubtedly necessary for
our south, where cattle breeding has always meet with unsurmountable
obstacles in the shape of the lack of fodders.

And so a correct seed rotution based not onty on a seed chanp:e
but also on root chang,e, is a great remedy for contending against dro-
ugfit, as it averts tlie perrennial drying up of tfie root-infmbited soil layer.

The extirpation of weeds on the whole space of the land possession
and a correct rotation of crops with a persistent alternation of cereal
grasses and thourough ploughed plants, are measures of fighting against
drought which are accessible to every farmer and their accomplishment
is not dependent upon the nearest neighbours.

But for all that the quantity of atmospheric deposits in steppe
black-soil districts is so small that its increab-.ig is only desirable. If
the adoption of the above technical measures and the organization of
seed rotations depend only upon the wishe^' of separate farmers and are
under the power of every separate person, a change in the climatic

— 47 —

conditions as regard the quantity of atmospheric water may only be taken
in hand by the government or some other large administrative unit.

An increase in the qnantity of atmospheric water however improbable
it may seem, is quite possible, if the humidity of the air in a given
dictrict increases: for we know that the more the air of that district is
saturated with water vapour, the more abundant the fall of deposits. An
increase in the quantity of water vapour in the air is possible when there
is increased evaporation on a more or less wide areas of a given district;
and this latter may be possible, by opening up here wide water expanses
for the steppe — ponds for instance or by increasing the quantity of plants
which exhale a great deal of water, such as trees. The making of
ponds in the steppe valleys although not presenting any great difficul-
ties and might be made even profitable by the artificial breeding of fish
theirein. does not guarantee a favourable solution to the problem; for two
dry years in succession are capable to destroy even well made ponds.

The preservation of the existing waters and the raising of new
ones upon the ground surfaces can only be undertaken by government, as
it is not a suitable thing for private initiative.

A much greater chance of success is offered in the increase of ar-
borial plants on fields. I do not speak of making forests on the steppe, like
our steppe experimental schools of forestry did; but of planting trees rather
of a garden than of a forest character, on large steppe areas or even on
whole steppe expanses, of planting the boundaries between fields, along
paths and generally on all boundary areas not utilized now. At the pre-
sent time, with developement of our farm culture, tree planting is the
most urgent need of these farms. And the preservation of the young sa-
plings is now much facilitated here, in comparison with the peasants
fields in settlements. If mulberry trees were used for that purpose, it would
raise our silk- worm breeding which has thriven now, thanks to the easier
method of dealing with the cocoons, but held back by the absence of
mulberry trees, which have not been cultivated by our foresties in pro-
portion to the demands. Such single or double rowed tree planting, dra-
wing up water from deep soil horizons not accessible to field plants, could
screen off the wind, which blows with double force, on our bare steppes,
compared with western Europe throughout the whole year, bringing up
the speed to 14 metres per second sometimes for whole weeks.

The again tree planting on the steppe will serve as the strongest
barrier against injurious insects, as the greatest mass of them do not
rise in their flight highe .han the average height of trees. From injurious
insects especially the hessian and sweedish Hies, then the sawer, and the
winter corn worm, millions of poods are absolutely lost every year. It is
impossible on the steppe to adopte any remedy against them, and the

— 48 —

constructon of tree barriers, even single rowed, but sufficiently thick, ap-
pear to be the only means of contending against injurious insects.

Reckoning the total of all that has been written, we come to the
conclusion that the measures against drought which may be adapted by
each farmer individually are: the unsparing destruction of weeds on fields
throughout the whole year and crop rotations based on the principle not
only of a seed change but also of a root change. We saw a proof of
the incontestability of these measures in the laws governing the circula-
tion of water in the soil, and if we do not reckon with them, it means
being always under the threat of drought. The reader is perhaps not
satisfied with such a simple solution of the question: but then the truth
is always simple.

Works by the same author.

The Derebchin Experiment Field. Book I. Kieff, 1889.
The cultivation ol colza and rape. Kieff, 1892.

The work of the commission on the inventary of estates, under the
supervision of the Kieff farming society and farming industry (with
the exception of the material from the inventary of the Smeliansky
estate) under the editorship D. I. Pikhno. Book I. Kieff, 1893.
The Derebchin Experiment Field. Book VI. Kieff, 1894.
The Derebchin Experiment Field. Book VII. Odessa, 1895.
The Odessa Experiment Field. I year (1895). Odessa, 1896.
The soil-geological borer, system V. Rotmistrov. Odessa, 1897,
The project of the organization of experiment fields in Russia.

Odessa, 1898.
The Odessa Experiment Field. II year (1896). Odessa, 1899.
„ „ „ „ III year (1897). Odessa, 1901,

„ „ „ „ IV year (1898). Kieff, 1901.

„ „ „ „ V year (1899). Odessa, 1902.

„ „ „ „ VIII year (1902). Odessa, 1903,

„ „ „ „ IX year (1903). Odessa, 1906.

The circulation of water in the soil of the Odessa Experiment Field.

Odessa, 1907.
The Odessa Experiment Field. X, XI, XII years (1904—1906). Odessa, 1907.
Results of the Odessa Experiment Field. Odessa, 1907.
The Odessa Experiment Field. XIII year (1907). Odessa, 1909.
The localities in which the roots of cultivated plants of one years

growth. Odessa, 1909.
The root-system of cultivated plants of one years growth (with the

analysis of bedcultivation of Demchinsky). Odessa, 1910.
A brief precept on cultivating the cotton plant. Ill edition. Odessa, 1911,
The course of methods of field experiment. II edition. Odessa, 1912.
The Odessa Experiment Field. XIV year (1908). Odessa, 1913.
„ „ „ „ XV year (1909). Odessa, 1913.

„ „ „ „ XVI year (1910). Odessa, 1913,

„ „ „ „ XVII year (1911). Odessa, 1913.

The Odessa Experiment Field. XVIII year (1912). Odessa, 1913.

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