极端干旱区咸水滴灌林地盐结皮对土壤蒸发的影响

由于长期使用高矿化度咸水滴灌，土壤盐结皮在塔里木沙漠公路防护林带内广泛发育，它会对林带土壤蒸发过程产生重要影响。采用田间取样分析和微型蒸发器（MLS）人工控制试验相结合，分别研究了一个灌溉周期内盐结皮影响下林间裸地和防护林带内的土壤蒸发过程。结果表明，土壤水分蒸发量自表层向下层逐渐减少，且有盐结皮的土壤蒸发量小于无盐结皮土壤；土壤日蒸发量随着含水量的降低而逐渐减小，有盐结皮土壤前期高于对照，而后期低于对照；土壤累积蒸发量随着时间的变化逐渐增大，但增加量逐渐减小，有盐结皮土壤累积蒸发量小于对照；盐结皮对土壤蒸发的抑制效率随着时间的变化而不断降低，但裸地的降低速度高于林地；盐结皮抑制土壤水分蒸发的效果明显。

Effects of salt crust on soil evaporation condition with saline-water drip-irrigation in extreme arid region

Soil salt crust develops widely in the Trim Desert Highway Shelterbelt, and it has significant effect on soil water evaporation process. Field sample analysis and control experiment with Micro-Lysimeters were used to study soil evaporation process affected by salt crust during one irrigation cycle. The results showed that soil evaporation reduced gradually from soil surface downwards, and the evaporation from soil with salt crust was less than that without salt crust; daily evaporation reduced gradually with the decrease of soil water content, daily evaporation from soil with salt crust was higher than that without salt crust at earlier stage and lower at later stage; cumulative evaporation increased gradually, but rate of increment reduced gradually, and cumulative evaporation from soil with crust was less than that without salt crust; inhibition efficiency of salt crust on soil evaporation reduced gradually, but bare land reduced faster than shelterbelt; salt crust can inhibit soil evaporation effectively.