Open Journal of Forestry
2012. Vol.2, No.3, 116-120
Published Online July 2012 in SciRes (
Copyright © 2012 SciRes.
Fundamental Environmental and Landscape Forming Influence of
Close Grass Cenosis on the Moisture Circulation
Alexander Y. Rakov
The Stavropol State Scientific Institution of Agriculture, Stavropol, Russia
Received February 21st, 2012; revised March 25th, 2012; accepted April 8th, 2012
The condensation of transpiration and advective water fallows (further—the phenomenon) under the
close grass cenosis can be compared to the quantity of precipitation. The phenomenon depends on physi-
cal and meteorological features of the closed grass cover. For instance, close grass cover halts a large part
of solar radiation at the daytime. Effective emanation and turbulent exchange cool the soil to a dew point
and lower. The phenomenon forms another landscape. There are also a number of other fundamental
consequences of the phenomenon. Thus, biologolisation of farming and forestry: Growing of forests and
agrocenosis with grasses (present-day weeds) that may serve as activators for forests and grasses; Culti-
vated plants selection, allelopathically compatible to some definite weeds; as a result of such a selection
weeds may be found and transformed into activators. To fight against drought, desertification the impor-
tance of the phenomenon is obvious. Flooding in the Western Europe may be connected with the named
phenomenon as this resource in connection with climate change is, probably, growing.
Keywords: Condensation; Transpiration; Fundamental Consequences
It is very important to define the elementary unit of (agro)
landscape—facies, as an atom in physics or a molecular in
chemistry. Sukachyov (1972), Ramensky (1971) have shown
the leading part of vegetation in such allocation. Beruchashvili
(1990) has proved the geophysical approach to this allocation:
facies’ borders are the lines dividing territories with different
fito-, geo- and energy mass—solar and other kinds of energy,
vegetation, soil, hydro- and geology.
As for agrolandscape, such an approach is the most rational.
It is obvious that borders of agrofacies are the borders of crop
rotation fields. As a result, agrofacies, as well as crop rotation
fields, are changing not only in space, but also in time.
Main phyto- and geomass in agricultural production is crop.
At the beginning of the XX-th century wheat yield of 6 - 8 hun-
dredweight per hectare was considered as a good crop. Nowa-
days in droughty steppes wheat yield reaches 60 - 80 hundred-
weight per hectare without an irrigation that is equivalent to
18 - 24 hundredweight per hectare of general dry organic sub-
stance. Even if we take into consideration all the precipitation
during a year, for example 500 mm (0.5 m—forest-steppe) and
refer to this crop quantity, the final field transpiration coeffi-
cient will make only 0.5 × 104 hundredweight per hectare pre-
cipitation forest-steppe tons of water ÷18 or 24 = 208 - 278,
where 104 is the area of 1 hectare in square metres and ÷ is a
division mark.
At the same time all the irrational expenses are ignored: ex-
penses on evaporation, drainage, filtration. This elementary
mathematics shows that except precipitation there is another
very powerful source of humidifying. In our opinion, this
source of humidifying is, first of all, the condensation of tran-
spiration vapour at the daytime. While cooling the active sur-
face by effective emanation, turbulent exchange and with the
flow of humid air: before and during the precipitation at the
vegetation period and in winter at advection of warm humid
air—the process of water vapour condensation is being ampli-
fied by the mentioned advection.
It is also well-known that a close grass cover and a water
vapour halt a large part of solar radiation. All these factors to-
gether create a favorable conditions for condensation of tran-
spiration and advective water vapours in soil (further the phe-
nomenon) under the herbage.
The majority of researchers conclude the insignificant quan-
tity of the phenomenon in soils without herbage. But Ko-
loskov (1937) has assumed the possibility of the advective fal-
low condensation after strong cooling of the soil and the tran-
spiration fallow at the daytime under the quite strong produc-
tive herbage, considering the latter not as the coming of water,
but as the savings of discharged water from soil. Indirectly this
phenomenon is proved by a strong variation of field transpire-
tion coefficient within one crop. This hypothesis is proved by
of Izmailsky (1949) at the end of the XIX-th century, who has
defined that the soil under more productive crop cenosis is
damper during a year in comparison to the less productive de-
graded virgin soil.
As for foreign authors, R. Sleiter and I. Mackelroy (1964) as-
serted that the maximum possible dew takes place under a high
bushy vegetation in deeply mulched soil. In their opinion the
quantity of maximum condensation (–Emax) is proportional to
radiation balance and was determined by the following formula:
(–E)max = (s ÷ (s + γ)) × /R ÷ L/,
where s—the quantity connected with specific moisture;
γ—psychometric constant;
/R ÷ L/—the module of the radiation balance relation to the
latent heat of vaporization;
÷ and ×—division and multiplication marks.
It is necessary to underline that the radiation balance is de-
fined, first of all, by a daytime solar radiation.
According to the researchers, quantity (s ÷ (s + γ)) varies
from 0.4 to 0.8 and the condensation rating can reach hundreds
in mm.
Research Technique
To study this phenomenon not analytical, as before, but
synergetic approach is acceptable: soil and plant are integration.
Researches were carried out in 3 agroclimatic zones of the
Stavropol territory: the extremely droughty (I zone: Achiku-
lakskaya scientific research experimental forestry station—
SREFS), droughty (II zone: Prikumsky experimental breeding
station—PEBS and the Limited Liability Company “Stavro-
pol-Caucasian”) and insufficient moistening area (III zone: the
experimental production farm “Mikhailovskoe” and the educa-
tional farm of the Stavropol State Institute of Agriculture). At
first moisture measurements in different agrolandscapes were
carried out by a thermostatic weight method at a depth of 11,5
m, then by a neutron moisture measurement—up to 25 m. The
data were processed by computer programs—statistically. The
total loss of moisture (balance): all the precipitation from the
moment of crops sowing plus loss of moisture from the ob-
served soil profile were referred to all the crop. The dew point
of the air under the herbage was defined and then compared to
the soil temperature. The possibility of the phenomenon was
defined lysimetrically and by difference calculation of accepted
transpiration and field coefficients (TC and FC), that is [450 –
208 (278) × 18(24)]/= 310 or 581 mm. Values in brackets mean
variations, ×—a multiplication mark. The results of the re-
searchers are resulted in Table 1.
The general crop of dry organic substance of agricultural
crops is equal to the tripled grain yield, doubled hay yield or
dry above-ground mass. Tables 1 and 2 are interconnected:
from the data of the first one the data of the second follows.
Results of Researches
We (Rakov and others, 1982, 1994, 1997, 2004, 2007, 2008,
2009) have proved the hypotheses of Koloskov (1937), R. Sle-
iter and I.Mackelroy (1964) of the possible importance of tran-
spiration or advective water fallows condensation and the si-
multaneous display of these processes.
The analysis of soil temperature and dew point according to
our data (Rakov, 2004, 2008) and the data described in litera-
ture (Shulgin, 1972) shows their favorable combination under
the close herbage for the named phenomenon beginnings. Un-
der it the soil temperature (12˚ - 18˚) at the daytime at the
depths to 30 sm, as a rule, is lower or is equal to a dew point
(13˚ - 21˚) at the 10 cm height of the soil surface.
It is known that soil thermal capacity and heat conductivity is
high enough that promotes the heat abstraction, allocated at
The most favorable conditions for the phenomenon take
place during the downpours and after them under the vegetating
close herbage, because: 1) the soil is cooled not only by effec-
tive emanation, but especially intensively by a wind, precipita-
tion, physical evaporation (a turbulent exchange); 2) intensive
advective fallow of atmosphere is raising a dew point; 3) ther-
mal capacity and heat conductivity of soil are at maximum.
It is proved by experimental data: while precipitation the
moisture level under the close herbages often exceeded their
quantity and ground waters have raised. Minimum accumula-
tion of a moisture during the autumn-winter period in observed
profiles was marked as well (for example, from 04.09.72 to
14.03.73 in Achikulakskaya SREFS). We connect it with the
establishing of equilibrium state since autumn (Rakov, 1997,
2004). This state hides the condensation phenomenon, espe-
cially during the vegetation period.
The most considerable moisture losses take place after har-
vesting and during cultivations that is typical for all our obser-
vations (Table 2).
Lysimetrical measurements also helped to establish the fact
that there are periods when to a lysimeter with the model of
surrounding soil under the close herbage comes more water,
than it comes to a soil raingauge. It is possible only at the ex-
pense of condensation of advective or transpiration water fal-
lows or each of them together. The quantity measured in such a
way is reduced by physical evaporation. However quantities
(45.9 - 75 mm) were received comparable to precipitation that
is proved statistically (Rakov, 1982, 2004).
Possibility and importance of moisture condensation quantity
Table 1.
Field transpiration index and phenomenon rating depending on crop and yield under multi closed grass.
Place, area*, year Ground layer,
m Crop General
yield h/h
Precipitation balance,
mm**** TC FC Phenomenon
rating, mm
LLC “Stavropol-Caucasian”, II, 20070 - 1 Winter wheat 18.7 366 –466 450 249 376
“The same, 2008 0 - 1 Winter barley 20.8 361 –457 258 220 79
SREFS, I, 1972 0 - 4 Winter rye 6.7 201 –136 500 203 199
The same, 1973 0 - 4 Virgin lands hay0.6 184 –214 - 3567 0
EPF “Mikhailovskoe”, III, 1987 0 - 7 Silage corn 6 81 +182 325 –303** 377
The same 0 - 9 The same 10 390 –171 325 171 154
The same, 1988 0 - 7 Triticale 7.7 430 –251 475 326 115
PEBS, II, 1993 0 - 24 Winter wheat 8 316 –274 450 342 86
The same, 1993 0 - 24 Winter barley 8 316 –184 258 230 22
The same***, 1996, May 0 - 24 Winter barley 5 195 –106 258 212 23
Notes: areas: *I: extremely droughty, II: droughty, III: of insufficient moistening; **under the silage corn with the abundance of weeds FC became zero due to the phe-
nomenon; ***per verdurous masses; ****one should take into account loss of moisture from the profile of Table 2.
Copyright © 2012 SciRes. 117
Table 2.
Moisture balance depending on the biomass.
Date Crop Yield СОВ,
hundredweight per hectare*
Rainfall for the period,
Total moisture,
Moisture balance,
Ground water
level/profile, m
1 2 3 4 5 6 7
Achikulakskaya SREFS
05.09.72 virgin lands 0 326 -/0 - 4
07.03.73 virgin lands 0 82 397 –11 -/0 - 4
26.06.73 virgin lands 0.6 (hay) 184 367 –214 -/0 - 4
11.10.73 virgin lands 0 114 260 –221 -/0 - 4
20.09.71 winter rye corn shoots 320
28.03.72 winter rye till 1,0 185 456 –49 -/0 - 4
24.05.72 winter rye 6.7 16 385 –87 -/0 - 4
26.06.72 Mowed 0.3** 42 337 –90 -/0 - 4
23.08.72 “Mowed” 0 95 308 –124 -/0 - 4
Experimental production farm “Mikhailovskoe”
till 0,5 1477 7.7/0 - 7
30.06 - 16.07.87 silage corn 6 81 1740 +182 2.9/0 - 7
crops 1158 -/0 - 9
30.04 - 02.09.87 the same 10 390 1377 –171 -/0 - 9
1 2 3 4 5 6 7
12.08.87 Mowed 0 29 1589 –180 4.7/0 - 7
03.05.88 Triticale 1.5 366 1596 –359 6.7/0 - 7
11.05.88 Triticale 2.6 34 1691 +61 7.0/0 - 7
30.05.88 Triticale 7.7 30 1768 +47 3.4/0 - 7
Prikumskaya experimental breeding station
07.12.90 virgin lands 0 2555 -/0 - 24
17.04.91 virgin lands 0.5 (hay) 116 2630 –41 -/0 - 24
22.05.91 virgin lands 0.5 (hay) 84 2623 –91 -/0 - 24
04.07.91 virgin lands 0.5 (hay) 137 2649 –163 -/0 - 24
07.08.91 virgin lands 0.5 (hay) 15 2584 –80 -/0 - 24
21.10.92 winter barley 1.0 3252 -/0 - 24
28.04.93 winter barley 3.0 178 3404 –26 -/0 - 24
24.06.93 winter barley 8.0 138 3384 –158 -/0 - 24
24.08.93 harvested 0 143 3309 –218 -/0 - 24
30.10.95 winter barley 1.0 3333 -/0 - 24
22.04.96 winter barley 3.0 153 3369 –117 -/0 - 24
21.05.96 winter barley 5.0 42 3422 +11 -/0 - 24
17.07.96 harvested 0 74 3326 +22 -/0 - 24
23.10.96 hulling 0 57 3323 –60 -/0 - 24
20.10.92 winter wheat 1.0 2926 -/0 - 24
26.04.93 winter wheat 3.0 178 2885 –219 -/0 - 24
1 2 3 4 5 6 7
23.06.93 winter wheat 8.0 138 2968 –55 -/0 - 24
23.08.93 Hulling 0 143 2910 –201 -/0 - 24
LLC “Stavropol-Caucasian” (according to М. А. Sirota)
2006-2007 winter wheat 18.7 366 100*** –466 -/0 - 1
2007-2008 winter barley 20.8 361 96*** –457 -/0 - 1
Notes: *all the dry organic substance; **after-grass.
Copyright © 2012 SciRes.
Copyright © 2012 SciRes. 119
of precipitation in soil are proved by calculations of field tran-
spiration factors (FTF) when for the volume of received yield
all the spent moisture is referred, including physical evapora-
tion. In spite to it their quantity under close productive herbages
in many cases appears to be much less than common obviously
genetic ЕС (according to (Grodzinsky, 1972)—minimum quan-
tities were taken into consideration). It is possible only if the
named phenomenon has a considerable quantity, that varied at
such definition from 0 to 430 mm (Table 1). With the quanti-
ties of the phenomenon, comparable to precipitation, funda-
mentally different landscapes are formed as it was mentioned
Protective forest plantations themselves drain the soil during
the vegetation (Rakov, 2004, 2007); at the same time they pro-
vide spatial ameliorative effect on adjoining lands. The forma-
tion probability of close herbages with considerable quantity of
the transpiration and advective water fallows phenomenon in
soil is the greatest in the system of protective forest plantations.
It is well illustrated by a yield of winter crops (60 - 70 hun-
dredweight per hectare) in the “Stavropol-Caucasian” LLC at
the southern chernozems in the 2nd droughty zone without an
irrigation. This yield two times exceeds an average yield for the
last several years that considered to be rather productive (Table
FC varies depending on capacity of an observed soil profile
on moisture and the received yield. For winter wheat it varied
from 249 to 342. For rye and triticale—from 203 in the first
zone to 326—in the third that shows great moisture accumula-
tion role of close herbage, especially during the time of inten-
sive precipitation; in the case of winter barley FC decreased to
212. It had initially minimal FC, most likely being field but not
genetically caused. For corn with an abundance of weeds FC
appeared to be negative as its density reached 100%. Under this
corn (one should bear in mind the abundance of weeds and
heavy precipitation) was marked considerable accumulation of
moisture: level of ground waters has risen from 8 to 2.9 m
(Rakov, 2004). The rating of the phenomenon (Table 1) has
changed accordingly. Under the corn without weeds, but with
more yield volume FC has increased to 171. The rating of the
phenomenon has made 154 mm.
According to the received results it is possible to assume that
close herbage at plentiful precipitation functions, mainly, due to
the condensate moisture as in this case the sucking potential of
plants is minimum. The moisture t moves transit to the soil
depth till the ground waters, raising their level. Moisture supply
in this case sometimes even surpassed quantity of precipitation
The phenomenon has multipurpose value for sciences about
the Earth and on the earth: rationalization (farming biologiliza-
tion) and especially for landscape studying (Rakov et al., 2009).
And particular for:
landscape studying—the previous and following examples
shows the landscape changes under the influence of the
named phenomenon. More rational seems to be mentioned
above geophysical approach (Beruchashvili, 1990). Differ-
ently productive cenosis are different facies—units of a
landscape. This is especially rational for the agro landscape.
At the beginning of the last century the winter wheat yield
of 40 - 50 poods (8 hundredweight per hectare) was a good
crop. Now in Russia yields of 60 - 80 hundredweight per
hectare are possible mainly thanks to the named phenome-
non, selection, etc.; and this is different agro facies. Now let
us consider some examples on a landscape transformation
by a plant. Some badlands were formed on a plain (because
of the secondary salinization of soil) and on a slope (the soil
was ploughed up along a slope). By means of methods and
plant kinds of the Stavropol Scientific Research Institute of
Agriculture badlands have been transformed into productive
lands—so quite the different agro facies have been formed.
But according to the accepted theory of a natural landscape
the name of facies remained unchangeable though it contra-
dicts the common sense—they are called a plain and a
slope as before.
An irrigation—in addition to other reasons of water losses,
because of ignorance of the named phenomenon the majority
of the irrigated soils are impounded and subjected to secondary
Forestry—after the deforestation in zones of excessive
moistening in glades swamps are formed. To avoid this an
immediate afforestation is necessary.
Gardenings—it is necessary to find grass cenosis with an
abundance of entomophages to avoid chemistry downward
Selections, plant growing—it is rational to output the plant
varieties that are allelopathically compatible to some pre-
sent-day weeds. They will serve as activators for cultivated
plants. For example, wheat together with the annual lucerne
have already been grown for a long time in China. Chemis-
try application will be reduced. And so on.
To fight against drought, desertification the importance of
the phenomenon is obvious. Flooding in the Western Europe
may be connected with the named phenomenon as this resource
in connection with climate change is, probably, growing (Ra-
kov, 2007)
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