塔里木灌区棉田的水盐动态和水盐平衡问题探讨

Studies on Water-salt Dynamics and Balance of Cotton Crops Land in Tarim Irrigation Region

利用2004年在极端干旱的塔里木盆地绿洲棉田灌溉试验数据,对常规地面沟灌和膜下滴灌棉田在不同灌溉定额下水盐动态进行了研究,对节水灌溉与农田水盐平衡问题进行了深入探讨.主要结论包括:①在2700m3/hm2灌溉定额时,常规地面沟灌和膜下滴灌棉田在生育期0～60 cm土层积盐,膜下滴灌的积盐率(12.4%)要高于常规地面沟灌的积盐率(3.4%);②在小于6000m3/hm2的4种不同灌溉定额条件下,生育期棉田1 m土体上总体表现为积盐;③对于土壤初始含盐量高的新垦荒地,灌溉淋洗的作用要好于土壤盐分本底值低的土壤;④为了保持农田的水盐平衡,在极端干旱区需要进行非生育期以淋洗盐分为目的的灌溉.

Based on the experimental data of cotton crops land in Tarim Basin, it is described that the water movement and sah transport in arid cotton crops land under different irrigation norms and different irrigation methods. The related water-salt balance problems in irrigated farmland are also discussed in this paper. The main conclusions are as follows： ①the sah is accumulated in the 0- 60 cm soil layer under drip irrigation or ditch irrigation with the 2700 m^3/hm^2 irrigation water during cotton growing period. The salt accumulated rate is 12.4% for under-film drip irrigation and 3.4% for ditch irrigation.②It is universally existed that the sah accumulated in the 100cm soil layer during cotton growing period when the irrigation water is less than 6000 m^3/hm^2 with ditch irrigation. ③For the new cultivated wasteland with higher initial salt content, salt leaching results is better than the old farmland with lower salt content when the irrigation water is same. ④For keeping the water-salt balance in extremely arid agriculture land, irrigation is necessary during the non-crops growing season for salt leaching purpose.