不同植被覆盖条件下土壤水分蒸发的比较

 为探讨不同植被对当地土壤水分动态变化及其蒸发过程的影响,于2001年7—10月,对宁夏固原县4种不同植被覆盖下土壤水分蒸发做了对比研究。在观测期内,不同条件下土壤水分蒸发的强弱依次表现为,弃耕地>华北落叶松林地>铁杆蒿+长芒草地>中国沙棘林地;各种条件下,土壤水分蒸发在生长季的旺盛时期(7—8月)要显著高于生长季后期(9—10月)。土壤水分蒸发的昼夜分段测定表明,在观测期内,土壤水分的蒸发在夜间出现了“负平衡”,尤其进入9—10月以后,这一现象更为突出,说明夜间凝结水数量大于相应的蒸发量。

Comparison of soil moisture evaporation under different vegetation coverage conditions

To probe into the effect of different vegetations on dynamic change of soil moisture and its evaporation process, soil moisture evaporation under four different vegetation coverage conditions were compared from July to October in 2001 in Guyuan county of Ningxia. The results indicated the order of soil evaporation intensity was abandoned land> Larix principis-rupprechtii Mayer. stand>Srtemisia vestita Wall.+ Stipa bungeana Trin. stand>Hippophae rhamnoides Linn. stand in the observation period. And soil evaporation in the quick-growth period (from July to August) was stronger than that in the later growth season (from September to October). Meanwhile, test of soil moisture evaporation day and night by stages showed that soil moisture evaporation in the night in the observation period appeared negative because especially after September and October, which indicated that amount of condensation water in the night is more than that of evaporation accordingly.