灌溉后不同处理方式对土壤水分蒸发过程的影响

土壤蒸发是土壤损失水分的重要途径,在北方旱区土壤蒸发失水量可达同期降水量的50%或更多,小麦全生育期棵间土壤蒸发占农田蒸散量的66%。因此,研究土壤水分蒸发过程和减少土壤表面水分蒸发途径对于寻找高效合理的水资源利用方式具有重要意义。利用称重式蒸渗仪初步研究了灌溉后不同处理措施对土壤水分蒸发过程的影响。结果表明,秸秆覆盖和高留茬对土壤水分蒸发的抑制作用主要表现在灌溉后土壤含水量较高的阶段内;天气晴朗条件下日蒸发强度在10:30左右即达最大值,秸秆覆盖和高留茬处理使其出现时间滞后;土壤含水量较高时松土对土壤水分蒸发无抑制作用,而在土壤含水量降低到一定程度时松土能明显抑制土壤水分蒸发。

Influences of Different Treatments on Soil Evaporation After Irrigation

Soil evaporation (Es) is considered to be an important component of evapotranspiration (ET). In dry land of North China, the amount of water loss from soil through evaporation can take up to 50% or more of precipitation in the same period and during wheat growing season, evaporation can take up to 66% of field evapotranspiration. Research on soil evaporation and how to reduce soil evaporation is significant to find an approach to an efficient use of water resources. This preliminary study was conducted to examine the influences of different treatment measures on soil evaporation using a weighing lysimeter system. Results show that straw mulching and high stubble can restrain soil evaporation after irrigation when soil water content is high. In clear weather, soil evaporation intensity reaches the maximum at about 10:30 am, but straw mulching and high stubble can make it later. Loosing soil when soil water content is high cannot restrain soil evaporation, but it can significantly restrain soil evaporation when water content is reduced to a certain degree.