硬壳覆盖条件下土壤冻融期水盐运动规律研究  

Study of Water and Salt Migration in Soil under Concrete Mulch during Freezing/Thawing Period

作　　者：李伟强[1] 雷玉平[1] 张秀梅[1] 田魁祥[1] 

机构地区：[1]中国科学院石家庄农业现代化研究所,河北石家庄050021

出　　处：《冰川冻土》2001年第3期251-257,共7页Journal of Glaciology and Geocryology

基　　金：国家科技攻关项目 ( 96 0 0 4 0 1 0 9) ;中日合作部分研究内容

摘　　要：采用大田试验 ,研究了水泥硬壳覆盖后冻融期土壤温度、水分、盐分的变化规律 ;采用室内土柱试验 ,研究了冻融交替时期土壤中的水盐运动规律 .试验表明 ,土壤水泥硬壳覆盖后土壤的冻结时间减少 ,冻结深度变浅 ;明显抑制土壤水分的无效蒸发 ;明显抑制土壤在融冻时期的土壤返盐 .同时由于“冻层滞水”在春季的融化 ,有淋洗表层土壤盐分的作用 ,使土壤表层脱盐 .土柱冻融试验进一步说明 ,土壤经冻融过程后 ,土壤中的水盐发生了重新分布 .Temperature and migration of water and salt in soil were studied in detail under concrete mulch through two in situ experiments and one big soil column experiment. The migration of water and salt was studied during the freezing/thawing period by way of indoor experiment. Soil temperature was studied at the same time. The results show that soil temperature under concrete mulch was 1～1.5℃ higher than that in the control plot, the freezing period was shortened, and the average freezing depth decreased 15 cm under concrete mulch as compared with than that on the control plot. Therefore, if soil was mulched by concrete, freezing area in 20 cm soil profile is less than that in the bare plot. At the same time, soil evaporation and salt accumulation in the surface were reduced during the freezing/thawing period. The results show that soil water rapidly moved upwards to the freezing layer, then frozen stagnant water formed. The amount of frozen stagnant water in the mulching plot is more than that in the control plot. The experiments show that 80 mm frozen stagnant water may form in one winter. The frozen stagnant water may seep with surface salt downwards after thawing in spring. The in situ experiments show that soil salt content under concrete mulch may decrease 20%～30%. Soil column experiment shows that water and salt in soil may migrate during freezing/thawing period. Soil temperature, soil profile structure, original soil moisture and depth of groundwater are the factors that affect water and salt migration in soil profile during the freezing/thawing period. Therefore, the migration of water and salt in soil during the freezing/thawing period is very complicated. Concrete mulching is similar to plastic mulching in decreasing water evaporation and salt accumulation in the surface, but concrete mulching is better than felt or straw mulching against water and salt accumulation in the surface. All experiments show that concrete mulching is a good method for improving saline soil.

关 键 词：硬壳覆盖 冻融期 水盐运动 土壤 温度 水分 盐分 室内土柱试验 

分 类 号：S152[农业科学—土壤学]