黄土塬区农田蒸散的变化特征及主控因素

发布时间：2019-07-21 20:32

【摘要】：蒸散是水量平衡和能量平衡的重要组成部分,也是农田生态系统水分消耗的主要途径。为探究黄土塬区农田蒸散的日动态变化规律,运用涡度相关法、土壤水分及常规微气象观测系统等,于2013年作物生长季(4—10月)对试验区农田作物(冬小麦、春玉米)蒸散特征及影响因素进行分析。结果表明,降水对蒸散的影响较为显著,降水过后的日蒸散量较降水前会有所增加;农田0~100 cm土壤含水量变异系数较大,土壤水分变化剧烈,作物根系的集中分布范围在0~80 cm之间,因此0~100 cm土壤水分主要参与蒸散过程;晴天蒸散的累积量大于阴天,晴天和阴天的日均蒸散量分别为4.5、3.8 mm d-1,相差0.7 mm d-1。阴天蒸散开始的时间较晴天晚,阴天条件下的蒸散更易受到气象因子的扰动;不同天气条件下净辐射均为蒸散的主要影响因子,蒸散速率与净辐射变化趋势一致,但在时间上滞后于净辐射;在不同的土壤水分环境条件下,蒸散的过程和强度差异较大,水分胁迫条件下,全天蒸散量水平较低,"蒸散高地"的持续时间较长;而水分相对充足时,全天蒸散水平较高,"蒸散高地"持续时间较短,维持较高的蒸散速率的时间较长。
[Abstract]:Evaporation is an important part of water balance and energy balance, and it is also the main way of water consumption in farmland ecosystem. In order to explore the diurnal dynamic variation of farmland evaporation in Loess Plateau, the characteristics and influencing factors of farmland crop (winter wheat, spring corn) evaporation in the experimental area were analyzed in 2013 crop growth season (April to October) by using vorticity correlation method, soil moisture and conventional micrometeorological observation system. The results showed that the effect of precipitation on evaporation was significant, and the daily evaporation after precipitation was higher than that before precipitation, the coefficient of variation of soil water content in farmland was large, the soil water content changed violently, and the concentrated distribution range of crop root system was between 0 鈮，

本文编号：2517397