Irrigation of the cultivated area with groundwater from vertical drainage wells

Abstract

In recent years, there has been a shortage of water resources in the basins of the Amu Darya and Syrdarya rivers, which is the result of the development of new lands for irrigation and the inappropriate use of water and land resources. A side effect of irrigation and land reclamation is the increasing flow of collector-drainage waters every year, which leads to a deterioration in the land reclamation state and pollution of water resources, which can lead to the ecological disaster of land and water resources. Currently, in the Republic of Uzbekistan, from the total volume of water resources of the Amu Darya and Syrdarya rivers, up to 68% is used for irrigation. Of this volume on the Republic territory, about 12% of collector-drainage waters of deteriorated quality are formed. With a shortage of water resources, they are used for irrigation. But irrigation with saline waters can lead to a deterioration in the land reclamation state. In this regard, new irrigation technologies are proposed, which can save both irrigation water and it is advisable to use underground pumped water for irrigation. Field experiments were carried out in the farm "Khozhilkhon-hozhi" in the farm named after A. Niyazov, Kuva district, Fergana region. A feature of the soil conditions in this farm is the small thickness of the covered fine earth, underlain by highly permeable gravel, strong and increased water permeability, with a deep groundwater level (GWL> 3 m). Large water losses are observed during irrigation. The calculation task was to determine how many hectares of land can be irrigated from one vertical drainage well, taking into account the irrigation time, inter-irrigation period, etc. The water-salt balance of the reclaimed lands for 2017-2019 was compiled. The water-salt balance showed that water supply and filtration from canals and atmospheric precipitation play the main role in the inlet part. In the consumable part, the main place is occupied by evapotranspiration and drainage flow. In general, a negative balance is formed on the territory annually by the type of a small salt carryover within 2.85 t / ha. On the territory of the farm and the experimental plot, cotton of the S-6524 variety was sown, the flow rate of the well is 30 l / s, the furrow consumption is 0.5 l / s. The composition of hypothetical salts in the pumped-out waters is calculated After the first irrigation of our field, the pumped-out water is diverted to the neighboring fields, while the first inter-irrigation period is 20 days. In the interval of these 20 days until the second irrigation of the cotton of the original field, it is possible to irrigate the same fields 5 hectares 8 times, in total 40 hectares of land. The experiments showed that irrigation with pumped water from vertical drainage wells did not have a negative impact on the yield of cotton. And the use of the recommended irrigation technology will reduce the shortage of irrigation water and improve the ecological situation of water resources.

The ways of using collector drainage waters for irrigation

“…), timely reclamation, and operational techniques (field planning, the use of advanced technologies and irrigation methods, the organization of optimal operating modes of irrigation and drainage systems, carrying out desalination measures, maintenance groundwater levels, etc.) [10][11][12]. The republic's territory has specific soil and climatic conditions; due to insufficient natural drainage and a high level of groundwater mineralization, a number of territories are "primarily saline".…”

Establishment of additional norms for irrigation water

“…where Km -coefficient, degree of mineralization of water (according to Km can be taken within 1.2-1.4). [5] For predictive calculations, the established patterns of actual reclamation regimes were calculated during long-term field studies of soil reclamation processes and elements of the water-salt balance.…”

River water quality Amudarya in territory of Karakalpakstan

“…Surface waters within the Republic of Karakalpakstan in the lower reaches of the Amu Darya River are polluted due to return waters with increased salinity, contaminated with mineral fertilizers and pesticides, as well as due to discharges of untreated industrial and domestic wastewater from settlements located in the upper and middle flow of the Amudarya River basin [5][6][7].…”