干旱区生态环境知识资源中心

In and and semi-arid regions, effluent from subsurface drainage is often saline and in the absence of natural Outlet, its disposal is a serious environmental threat. A field experiment was conducted on a sandy loam soil to evaluate the effects of conjunctive use of saline drainage water (ECiw = 7.5 - 9.0 dS m(-1); SAR = 8.5 - 12.7) and non-saline canal water (ECiw = 0.4 - 0.5; SAR = 0.6 - 1.0) in different modes on soil salinity build-up, growth and yield of wheat (Triticum aestivum) and succeeding sorghum (Sorghum bicolor). The results indicated that pre-plant irrigation with saline drainage water decreased the growth! and yield of wheat significantly. The effect was not significant when non-saline water was used for pre-plant irrigation. The mean relative yield of wheat irrigated with only saline drainage water was 63.0%. Substitution of nonsaline canal water for first two irrigations increased the yield to 97.4%. Alternate irrigations in different treatments resulted in 77.2 to 92.3% yields. Sorghum yield decreased significantly where all the irrigations were applied with saline drainage water to previous wheat crop. Increased soil salinity and alkalinity hazards were eliminated by the subsurface drainage during the ensuing monsoon period. This field study indicates that with the use of high salinity drainage water in conjunction with non-saline canal water for post-plant irrigation, good yield of wheat can be obtained without any serious soil degradation.