秋浇条件下季节性冻融土壤盐分运动规律

针对内蒙古河套灌区春季地表反盐的问题,采用田间试验的的方法对秋浇条件下季节性冻融土壤的盐分运动规律进行了分析。结果表明,秋浇在短期内只是将上层土壤盐分淋洗至下层,冻结初期才是盐分从田间排走的主要时期;在冻结和排水的共同作用下,冻结期土壤盐分运动规律复杂,导致冻结层储盐总量变化不大,而主要的返盐过程则发生在消融期。在经历整个试验期后,0～100cm和0～150cm土壤储盐量均有不同程度增加,说明秋浇并没有完全达到淋洗盐分的目的。另外,良好的排水条件在一定程度上抑制了盐分的向上累积,这一点在冻结期表现最为显著。

Salt movement of seasonal freezing-thawing soil under autumn irrigation condition

In view of severe salt accumulation in Hetao irrigation district, Inner Mongolia, during spring, salt movement of seasonal freezing-thawing soil after autumn irrigation was analyzed based on field experiment. Results showed that soil salt only leached to deeper layers in a short time after autumn irrigation, and they were mainly discharged from field during early freezing period. Influenced by both freezing and discharging process, salt movement was complex and resulted in little salt storage change of frozen layer during the freezing period, while the main process of salt accumulation happened in the thawing period. After the whole experiment period, salt storage in the layer of 0-100cm and 0-150 cm both increased, which indicated that the autumn irrigation did not accomplish leaching salt absolutely. It was also found that good drainage conditions inhibit salt upflowing in some degree, which presented significantly during the freezing process.