Soil salinity dynamics in irrigated fields and its effects on paddy‐based rotation systems in southern Kazakhstan

Abstract

AbstractAgricultural production in southern Kazakhstan has experienced significant economic difficulty since the 1980s, accelerating agronomic problems including the salinization of irrigated fields. A thorough understanding of the up‐to‐date situation of soil salinization and its effects on cropping systems is necessary in order to establish sustainable agricultural systems with avoiding land degradation for the region. This study examined the relationships between soil salinity, crop yield and affecting factors including local terrain for two farms. Both farms are characterised by a gentle slope, flat area and localised depressions. Most of the paddy fields showed wash‐out of salts during the irrigation period except in waterlogged fields situated in depressions. Rice yield was adversely affected by the remaining soil salinity, deep ponding water and insufficient drainage capacity in the lower part of the irrigation system. Salt accumulation in the upland fields appeared to increase with cropping years, and was associated with groundwater depth that became shallower at the lower parts of the irrigation systems, adversely affecting the crop growth in most fields. Since the cropping patterns had recently changed in the region, each pattern was compared against the recommendation of this study. Most patterns were concluded to be potentially effective for preventing soil salinization if conducted under an optimum economic and social system. Copyright © 2007 John Wiley & Sons, Ltd.