华北平原作物棵间蒸发占蒸散比例及减少棵间蒸发的措施

The proportion of the evaporation to evapotranspiration and the measures to reduce the evaporation in North China Plain

利用棵间小型蒸发器测定了华北平原主要作物冬小麦、夏玉米、大豆、谷子、高粱和棉花生长期间棵间蒸发占蒸散比例随生育期的变化。结果表明 ,这几种作物在整个生育期中棵间无效耗水大约占总耗水量的 1/4～ 1/3。影响棵间蒸发速率的主要因素除气象条件外 ,还有土壤表层含水量和作物群体叶面积指数。秸秆覆盖、中耕锄划、调控表层土壤根系分布等可作为减少土壤蒸发的有效措施。

The proportion of evaporation to evapotranspiration in different growth stages of main crops in North China Plain including winter wheat, summer corn, bean, millet, sorghum and cotton was determined by micro lysimeter. The result shows that one fourth～one third of total field evapotranspiration is consumed by the soil evaporation under canopy. The topsoil water contents and leaf area index (LAI) can affect greatly the soil evaporation under canopy except the meteorological factor. Straw mulching, cultivating and hoeing, regulating the root distribution in the topsoil are effective measures to reduce the soil evaporation.