Introduction
Uzbekistan is situated inside the limits of two river basins of Central Asia AmuDarya and Syrdarya, occupying their western and northwestern parts, where mountain systems of Pamir-Alay and Tin Shan drop down to flatlands. It stipulates a comparatively low flow of rivers in Uzbekistan as against Tajikistan and Kirgizia and dependence on neighbors in secured provision by surface waters, as only11-12% of all water resources in Uzbekistan are formed in its territory.
Water shortage and degradation of water and land resources quality are observed in the country everywhere. A substantial part of irrigated lands of the Republic suffers from salinization, high level of groundwater depth and watererosion, losses of agrobiodiversity nd other dangerous processes.
(Shavkat Khamraev, deputy minister of Ministry of Agriculture and Water Use of the Republic of Uzbekistan, cited from http://www.cawater-info.net/5wwf/national_report_uzbekistan.htm)
Agriculture in Uzbekistan is highly dependent on irrigation. Seventy-nine percent of land under wheat production is irrigated, and similarly high figures apply for cotton. Further, 93 percent of freshwater withdrawals go to agriculture. Due to the spatial variability of soils and climate, and access to water, infrastructure, and other inputs, many areas of Uzbekistanoutside of the Piedmont zone are unsuitable for high-value vegetable production and hence the reliance on more resilient, less input-intensive crops such as fodder for livestock in the desert and steppe zone. Most agricultural areas are within the Amu Darya and Syr Darya river basins, and these rivers provide approximately 70 percent of irrigation water (World Food Programme 2008).
The most pressing problems in agriculture in Uzbekistan include inefficient water use, soil salinization, wind soil erosion, and water soil erosion. Uzbekistan also has a need for proper drainage. Salinity costs Uzbekistan US$1 billion per year. Uzbekistan’s soils are high in salts, and irrigation leaches and deposits salts into groundwater or further along the catchment. Reusing water downstream for irrigation and rising groundwater cause problems with salinity. Specifically, 51 percent of irrigated land is salt effected, of which 4 percent is strongly saline, 17 percent is moderately saline and 30 percent is slightly saline. Of the 4.26 million ha of irrigated land, 20,000 ha are abandoned yearly due to soil salinity and uneconomically high pumping lifts (World Bank data). Soil erosion is also a pressing concern. FAO states that erosion from winds affects 50 percent of irrigated land and a significant area of rainfed and pasturelands, and water erosion affects 6 percent of irrigated and 20 percent of rainfed lands (FAO 2006). Anthropogenic effects that accelerate erosion and contribute to land degradation include poor cultivation practices, overgrazing, and salinization. ( Read more...)
A major concern in Uzbekistan as in many other countries is the declining productivity of crops, especially of rice, cotton and wheat. This is mainly due to water-induced land degradation (salinization, sodification, waterlogging or groundwater depletion), and loss of soil fertility with the sustained removal of nutrients associated with more intensive cropping and the inappropriate use of heavily subsidized nitrogenous fertilizers…
Experience of Central Asia demonstrates that an irrigation regime of agricultural crops is closely connected with natural and economic conditions and besides plants water consumption is determined by a number of factors:
1) Depth and mineralization of underground water,
2) Irrigation engineering (irrigation technique, irrigation and collector-drainage networks,
3) Mineralization of irrigation water,
4) Agro technology of cultivation
Thus regime of irrigation of agricultural crops on salted and drained lands should be based on complex analysis of water and soil conditions of the areas. (Ergash Karimov, 1974, Read more …)
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