Secondary salinization of soils and ways to prevent downstream of the Amu Darya

Abstract

In the history of irrigated agriculture there are many cases when due to severe soil salinity the yield was so low that it did not justify the costs incurred for cultivation of crops. Such lands were classified as unsuitable and were left without use for crops. Lands from suitable ones turned into unsuitable ones and were also often left out of use for irrigated crops, thus, among the old irrigated land masses there were many fallow lands, fallow fields and other vacant lands. The growth of salinity of irrigated soils in the Central Asian republics in the last 30-35 years has become almost ubiquitous. Both old and new irrigation systems bear heavy losses from growing soil salinity. More often secondary salinization in irrigated soils begins to appear even at relatively deep groundwater (3.5-4) in the form of seasonal (during summer) spot salinization of soils on microrelief elevations, on spots of irrigated fields bare from cultural vegetation.