CC BY
3
СОВРЕМЕННЫЕ НАУКИ И ОБРАЗОВАНИЕ
Khakimov A., candidate of technical sciences
associate professor Andijan Institute of Agriculture and Agrotechnology
Tursunov P.I., master Andijan Institute of Agriculture and Agrotechnology
Sirochov A.M., master Andijan Institute of Agriculture and Agrotechnology
WAYS TO IMPROVE THE EFFICIENCY OF WATER RESOURCES
USE ON IRRIGATED LANDS
Annotation: Analyzing the water balance equations at close (h = 1.0 -1.5m) and at (h = 3.0m) relatively deep occurrences of the groundwater level and using the data of a number of authors, it has been established that the maximum value of total evaporation is typical at close occurrences (h = 1.0-1.5 m) groundwater level. A decrease in the groundwater level leads to a decrease in the amount of total evaporation. This circumstance will make it possible to reduce the irretrievable losses of groundwater for evaporation.
Key words: water resources, total evaporation, salt balance, groundwater, irrigation rate, root layer.
The formation of various soils is associated with a different ratio of the main components of the water and salt balances, and different costs of water resources. This circumstance was reflected in the works of N.M. Reshetkina, I.P. Aidarov, E. Karimov, and others, who believe that the greatest consumption of water resources is typical for irrigated lands with a close (1... 1.5 m) groundwater occurrence (1,2).
To assess the difference in the consumption of water resources on irrigated lands, under different reclamation regimes, we analyze the changes in the total water balances at a close occurrence of the level (1... 1.5 m) of groundwater and its decrease to 3 m. m) equation (at h = 1... 1.5m) we get:
A Wo= ( O/'-O'r ) + (Fk" - F'k ) - ( E"- E' ) + [ ( P - O_)" - ( P_- O)' ]± + ( R" - R' ) - (D" - D' ) - ( "S"- "S' )..........(1)
Here: Or - net irrigation norm; eepage losses from the canals of the irrigation network; E - total evaporation (per year); P - O - underground inflow and outflow; P - pressure feed; D - drainage runoff;
C - surface discharge. Indices Or" and O'p refer respectively to balance sheets at h > 3 m and h = 1......1.5 m.
Consider the changes in the components of the blanc. Irrigation norms net. The results of summarizing numerous data on the values of net irrigation norms, at different levels of fresh groundwater, are shown in Table 1 (3,4,5,6,7, etc.).
Table 1
Changes in net irrigation norms for cotton-alfalfa crop rotations depending
on the level of groundwater.
UGV 1,0 1,5 2,0 2,5 3,0 4,0
"Or = Or I / Or 1 1,0 1,22 1,44 1,55 1,64 1,70
The given data show that Or" > O'r.
When the groundwater level drops from 1.....1.5 to 3 m, the net irrigation
norm for the cotton-alfalfa crop rotation increases by ~ 50%, which will require additional costs for the construction of the irrigation network. In accordance with what has been said
F"k = — Op" > F'k
■ O ' Op
(2)
R R
Much more difficult is the estimation of total evaporation, depending on the level of groundwater. This is due to the fact that total evaporation significantly depends not only on the regime of groundwater, but also on the moisture content of the root layer of the soil, the degree of shading by plants, salinity, and other factors. In this regard, we will evaluate the dependence E = f ( h ) for the main agricultural crops (cotton and alfalfa) with a known
approximation, using the available lysimetric data at soil moisture ( 0.6.....0.9)
HB ( 2.3, 4,5,6,7,8,9 etc.). As part of the collected data, there are evapotranspiration values that differ markedly from the general level (Table 2). To exclude the outstanding observations from processing, the critical values E" were used, selected from the condition so that their probability was not lower than the significance level a = 0.05, that is
R (Xp> x +tc ) = aiR (xi < x - to ) = a.....(3)
where xp and x1 are the maximum and minimum values of total evaporation;
o is the standard deviation; t is the normalized deviation depending on the significance level and sample size ( 10).Tablitsa 2
Cotton p ant Alfal fa
1,0m 1,5m 2,0 m 2,5 m 3,0 m 1,0m 1,5 m 2,0 m 2,5 m 3,0 m
14670 11886 8370 10900 7470 16450 13900 16700 13000 13630
9670 12619 8195 7030 13780 9320 17242 9570
6320 11552 7525 13210 12360 14871 9800 15060
7394 9880 9505 9713 14500 9200 17325 17730
16764 12280 8721 9037 15200 12568 15080 10800
13440 11460 7023 8731 8077 11737 9300 7300
7993 7512 7092 14218 8700 10400
9624 9068 7424 15738 10800 10800
9603 9845 6926 13641 10200 16631
5933 7816 6888 14934 7700 15181
13099 11098 12370 10460 15809 13610
12045 9803 8653 16163 10981 10864
11598 9540 6281 15240 12191 13562
8985 10201 10037 14059 15029
9110 8985 8776 12117 10723
6604 8806 11960 15223 15164
7537 9670 11221 15088 12001
8006 11880 11045 10727 14720
4751 1280 9386 9405 14832
4897 10867 9340 11997 13406
5623 12267 10450 11862 10420
7100 9346 10454 15352
14760 9014 8532 15694
10711 10400 12672 12910
14260 9270 13932 14760
13150 9584 7684
10945 9587 9300
12167 9020
12427 6570
10549 8191
12546
10934
12677
13333
11000
16060
12410
12450
14200
13380
The results of generalizations of data on the value of total evaporation are shown in Table 3.
Table 3
Values of "E" depending on the level of groundwater, thousand m3 / ha
culture The value of "E" at the level o ? groundwater, m
1,0 1,5 2,0 2,5 3,0
Cotton 10,9 11,6 9,9 9,8 9,6
plant Alfalfa 13,7 13,9 12,7 12,5 12,4
Rotation Weighted Average 11,7 12,3 10,7 10,6 10,4
The data obtained show that the maximum values of total evaporation are typical for irrigated soils with a close occurrence of fresh groundwater ( 1.... 1.5m ). A decrease in the groundwater level leads to a decrease in the amount of total evaporation, mainly due to the non-vegetation period.
Thus E" < E'. The decrease in E is small and amounts to 10....15%. The nature of the dependence E = f(h) is in good agreement with the dependence of the yield on the groundwater level (Figs. 1 and 2). [2,9,11].
The difference between the underground inflow and outflow (P - O )" - (P - O)' after lowering the groundwater level will increase due to an increase in inflow P" > P' and a decrease in outflow O" < O'. The pressure supply R" > R'
will change similarly, since Ah" > Ah'. When improving the irrigation technique, S = O or S"- S'. To assess the change in drainage flow, consider the balance
of groundwater:
y =
ymax
0,9 0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1 0
<j
A i ^^Y i xr * •tH ' S 5 ( ; ° X
X X * ( > • > /M 1 . K x W koO ' ¿X 1 X c * <1 -i—
i „ ; & 1 X 1 0 ( » o o * X J * S
K 9 o I
)
o-a
-i- • <..
1,0
3,0
3,5 h
sr
1,5 2,0 2,5
Figs. 1.1 Dependence of cotton on hgr 1-according to Legostaev; 2-according to Kiseleva; 3- irrigation regimes and hydromodular zoning of the UzSSR
1,5 2,0 2,5 3,0
Figs. 2.1 Dependence of yA- alfalfa on hgr 1-According to Amanov; 2- according to Efimov.
A W'g= q" - R' + ( P_- O)' - D'............ (4)
A W"g= q" - R" + ( P_- O) " - D".............( 5)
insofar asq" > O;q' < O; R" >R'; (P- O ) " > (P- O ) ' we get: A D= A q+A( P-O)+AR >O that is D" > D' Thus, changing the reclamation regime of irrigated lands in the Saz zone by increasing the depth of groundwater makes it possible to reduce unproductive evaporation and obtain additional water resources necessary for the further development of irrigation in the Syrdarya basin.
This gives grounds to say that a change in the reclamation regimes of irrigated lands in the Saz zone is a necessary element in the reconstruction of existing reclamation systems in the Syrdarya basin, which should precede the transfer of part of the Siberian rivers to Central Asia.
However, changes in the reclamation regime, with a decrease in the level of groundwater, are associated with a violation of the ratio between the components of the water and salt balances of irrigated lands, which requires an assessment of possible changes in soil processes and soil fertility. The main possible changes are due, on the one hand, to the fact that an expense item appears in the balance of surface and soil waters, in the form of descending currents of irrigation water (q), and on the other hand, a change in the water regime of the root layer of soils and a decrease in yield (Fig. 1 and 2).
These processes together lead to a certain decrease in the content of humus in soils, and an increase in the removal of mineral nutrients (NDK) to groundwater. A generalization of the literature data shows that there are no significant changes in soil fertility; the decrease in humus content does not exceed 20%, PPK - 5... 10% ( 13.14, etc.)
References:
1. Reshetkina N.M. O proektirovanii meliorativnyx rejimov na oroshaemyx zemel. - V sb.: Borba s zasoleniem oroshaemyx zemel. M.Kolos, 1967, p.31-36
2.Aydarov I.P., Karimov E. Nekotorye voprosy obosnovaniya meliorativnyx rejimov oroshaemyx zemel pri proektirovanii orositelnyx sistem. - Water Resources, 1974, № 2, pp.105-113.
3. Kisileva I.K. Regulation of water-salt regime in Uzbekistan. Tashkent,; Fan, 1973. - 145 p.
4.Vaksman E.G.Melioratsiya zasolennyx pochv yugo - zapadnogo Tadjikistana. Dushanbe,: Donush, 1976. -198 p.
5. Kats D.M. Influence of orosheniya on groundwater. M.; Kolos, p. 7-55
6. Reshetkina N.M., Yakubov X.I.Vertical drainage.M.: Kolos, 1978.-310p
7. Chapovskaya E.V. Isparenie gruntovyx vod v techenie goda (pri vozdelyvanii xlopchatnika).V kN.: Hydrogeologiya i melioratsiya pochv Tadjikistana. Dushanbe,: Irfon, 1969, pp. 21-37
8. Хакимов А., Карабаев А. Н. ОСОБЕННОСТИ ФОРМИРОВАНИЯ ПОЧВ САЗОВОЙ ЗОНЫ В ЕСТЕСТВЕННЫХ УСЛОВИЯХ //Universum: технические науки. - 2021. - №. 11-2 (92). - С. 72-75. https://cyberleninka.ru/article/n7osobennosti-formirovaniya-pochv-sazovoy-zony-v-estestvennyh-usloviyah
9. Хакимов А., Сабитов А., Саттиев Ю. Определение влагообмена между почвенными и грунтовыми водами //Актуальные научные исследования в современном мире. - 2020. - №. 2-2. - С. 86-89. https://elibrary.ru/item.asp?id=42781157
10. Мониторинг работы вертикальных дренажей при мелиорации орошаемых земель / A. Хожиматов, А. Хакимов, Д. Д. Хусанов, Ф. Х. Абдулхдков // Актуальные научные исследования в современном мире. -2019. - № 12-2(56). - С. 136-139. - EDN KYUOWZ. https://elibrary.ru/item.asp?id=42489774
11. Сабитов А., Хакимов А. Рациональный способ освоения склоновых массивов //Актуальные научные исследования в современном мире. - 2019. - №. 12-2. - С. 129-132. https://elibrary.ru/item.asp?id=42489772
