南疆种稻改良盐土的问题

种稻改良盐碱地是我国的传统措施之一.各地实践证明,种稻前后相比较,土壤脱盐效果显著,一般都能减少总盐量的20—80%,在整个剖面中以表层脱盐最高,为后作创造一个淡化土层,有利于作物生长.根据南疆各团场生产实践表明,有些种稻条田当年脱盐以后,在回旱一年、两年或三年的时间内,盐分又回升,有的恢复到原来的含盐水平.为什么土壤积盐的速度与强度如此迅速,要怎样才能巩固脱盐效果,这与土壤改良条件有着密切的关系.

THE RECLAMATION OF SALINE SOIL BY RICE CULTIVATION IN SOUTHERN XINJIANG

In the Tarim basin,one year of rice cultivation on soils of high salinity brought about a decrease in salt content to the extent of 20 to 80%.In the soil profile,desalinization is most remarkable in the ploughed layer.Under equal conditions,the longer the period of rice cultivation is prolonged,the thicker the layer of desalinization is formed.A great changes have taken place in the composition of the soil salts after rice cultivation.In a farm near Aksu,for example,the main component of salt in soil was mainly chlorides,which changed into sulphates ranging from 60 to 90% of total anions after four years of rice cultivation,at the same time,the sodium was replaced by calcium as the main component of cations up to 50-80% of the total cations.The desalinization and changes in the components of the salts after rice cultivation provided a favorable conditions for the succeeding crop.