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Section 11. Agriculture
Section 11. Agriculture
Mirkhasilova Zulfiya, Tashkent Institute of Irrigation Agriculture and Mechanization Engineers Tashkent city, Uzbekistan E-mail: [email protected]
WAYS TO IMPROVE THE WATER AVAILABILITY OF IRRIGATED LANDS
Abstract: The development of the use of water resources for irrigation leads to a deficit of fresh water, which leads to an aggravation of the problem of the distribution of water resources, the problem of salinization of soil degradation and a decrease in the productivity of agricultural production. The article deals with collector-drainage waters of the Ferghana Valley, which can be an additional source of irrigation. Most of these waters are discharged from irrigation fields and groundwater from vertical drainage wells, which have a mineralization in the range 1.0-1.5 g/l and can be used for irrigation.
Keywords: water resources, hydrological, mineralization, drainage, water hydro-geological, region, problems, vegetation.
Introduction. In Uzbekistan, water resources play a decisive role in the development of the national economy of arid regions, they are the main limiting factor in achieving stable levels of social development. At the international conference devoted to the water problem in Tashkent and other forums, it is said about developing measures to protect the environment: it is necessary to consistently improve the protection of the republic's water resources; continue to implement a set of measures to protect water bodies, as well as improve the state of rivers and reservoirs; improve the efficiency of sewage treatment plants and installations; ensure the rational use of land and water resources. It is noted that at the present time various kinds of natural disasters are expected around the world, some of which are related to global warming. One of the inevitable consequences of this process, according to leading experts, scientists, will be the change in the existing hydrological cycle of regimes, which will cause various negative consequences depending on the geographic location of the region. Almost now we are witnessing that in Uzbekistan there is a sharp increase in the number of low water years, which leads to an aggravation of the problem of distribution of limited water resources and their use, problems of salinization of soil degradation and a decrease in the productivity of agricultural production [1, 30-35].
Materials and methods of investigation. These circumstances dictate the need to develop a scientifically grounded complex of water-saving, meliorative, ecological and other
measures that ensure stable high yields of agricultural crops with the least expenditure of water and logistical resources, which determines the urgency of the problem.
The development of the use of water resources for irrigation and industrial needs leads to a deficit of fresh water, which is especially acute in Uzbekistan in recent years. At the same time, there is a rather large volume of collector-drainage water in the republic. Currently, in the Ferghana Valley, the total drainage of collector-drainage water is 80 m3/s in the Fergana region, 36 m3/s in the Andijan province, and 50 m3 /s in the Namangan region.
Most of these waters are discharged from irrigation fields and groundwater from vertical drainage wells, which have a mineralization in the range of 1.0-1.5 g/l and, according to the assessment of the quality composition, are quite suitable for irrigation of crops (Figure 1).
However, the pumped water is discharged into the collector and, in case of possible use, is taken by the pumps already in the form ofcollector-drainage waters ofdeteriorated quality. Taking into account the fact that pumped water is an internal reserve of each farm, these waters could serve as an additional source of fresh water for irrigation during the growing season. The most promising are the farms of the Kuva, Rishtan and Altyaryk districts, where a sufficient number of vertical drainage wells are concentrated with an average production rate of up to 40-50 liters per second and with a mineralization of groundwater not exceeding 1-1.5 g/l. The use of pumped out water can be
WAYS TO IMPROVE THE WATER AVAILABILITY OF IRRIGATED LANDS
carried out by transferring the vegetation irrigation of certain sections of the economy to full provision with pumped-out wa-
ter. One of the important issues is the establishment of areas for which the volumes of pumped water are sufficient [2, 294].
Figure 1. Mineralization of groundwater occurrence areas in the Fergana region
The possibility of transferring vegetation irrigation to the full provision of pumped-up water taking into account the hydro-geological and meliorative conditions of certain areas of the Fergana region is justified by the solution of the following issues:
- Identification of a zone with fresh groundwater horizons in conditions. The existing vertical drainage well system;
- determination of actual production rate of vertical drainage wells by zones fresh horizons of groundwater;
- evaluation of the meliorative state of irrigated lands;
- allocation of specific farms and areas of potential for translation vegetative watering pumped by existing water; Vertical drainage wells;
- evaluation of technical condition of vertical drainage wells;
- development for some farms of technology of transfer of vegetative watering with pumped-out water of vertical drainage.
In the region 1264 wells ofvertical drainage are exploited. The condition of the low-water year provides for the maximum operation of the vertical drainage wells for the use of pumped water for irrigation. Forecast calculations of general and private water-salt balances are based on the operation regimes of vertical drainage wells in low-water years under which the maximum effect on the creation of favorable water-
salt regimes of soils from the rational operation of drainage will be ensured.
Results of studies and their discussion. Taking into account the work of the vertical drainage wells and the technical condition of the horizontal drainage, and also on the basis of predictive calculations of water-salt balances for the conditions of the low-water year, the possible resources of collector-drainage waters are determined by regions and their qualities are estimated. Taking into account the quality of the collector-drainage water and the categories of drainage of the old irrigation zone, the volume of collector-drainage water is recommended for use in irrigation of crops in low-water years. In order to ensure uniform water availability, to reduce the damage to the harvest in the region based on calculations of the quantity and quality of mineralized waters, soil conditions with a planned linkage according to drainage categories, we recommended, on the basis of calculations, a redistribution of the water limit from the source between the areas within the established limit for the region.
By covering the deficit of irrigation water with drainage water and rational redistribution of the water limit from the source, the water availability in the districts between the districts is equalized and 50-70 percent, water availability in the region will increase from 0.68 to 0.98 percent.
References:
1. Yakubov M. A., Yakubov H. E., Yakubov Sh. Kh. Collector drainage runoff in Central Asia and assessment of its use for irrigation // Scientific Information Center of the Interstate Water Commission.- Tashkent-2011. From P. 30-45.
2. Mirhasilov Z. K. Ways to reduce the discharge of polluted water into rivers and the possibility of full provision ofvegetative irrigation with pumped-out waters of vertical drainage in the farms of the Fergana region // Collected Scientific Works for the 80th Anniversary of SANIIRI them. VD Zhurina From - P. 294-296.
