华北平原冬小麦相对蒸散与叶面积指数及表层土壤含水量的关系

The relationship between relative evapotranspiration and leaf area index and surface soil water content in winter wheat field of North China Plain

摘要: 冬小麦相对蒸散(农田蒸散量ET 与自由水面蒸发量ET_o之比)表征冬小麦受土壤水分和作物生长状况制约下的耗水规律。冬小麦生长季利用大型蒸渗仪测定农田蒸散，用E601型水面蒸发器测定水面蒸发，并用平行观测方法测定叶面积指数，分析冬小麦相对蒸散与叶面积指数和表层土壤含水量的关系，并建立了冬小麦返青～收获期相对蒸散与叶面积指数和0～60cm表层土壤含水量的经验公式为RE=In ( )*(1．03+0．68LAI)。在田间条件下由RE和ET_o推算出小麦耗水量ET,并可用于冬小麦适时、适量灌溉管理。

Abstract: The actual evapotranspiration and water surfaca evaporation are observed by weighting lysimeter and E601 evaporation pan in the growing season of winter wheat in the North China Plain．The relative evapotranspiration of winter wheat(the ratio of the actual evapotranspiration to water surface evaporation)shows the characteristics of water depletion of winter wheat determined by soil water content and crop factors．Based on the analysis of the relationship between relative evapotranspiration and leaf area index and soil water content．an empirical function has been constructed ：RE =1n(1+ )(1．03+0,68 LAJ)．In the fie1d condhitions，the eva1uation of actual evapotmnspimtion by re1ative evapotranspiration and water surface evaporation provides a helpful information for irrigation scheduling of winter wheat．