利用时域反射仪测定的土壤水分估算农田蒸散量

简要介绍了时域反射仪（TDR）测定土壤含水量的原理和方法，根据TDR实测的土壤水分和农田水量平衡原理，估算了冬小麦生育期内不同供水条件下的农田蒸散量，探讨了TDR探针不同埋设方式对测定土体贮水量以及对估算的农田蒸散量的影响，根据充分供水区测定的最大可能蒸散量、非充分供水区的实际蒸散量，以及用气象资料计算的参考作物蒸散量，分别计算了冬小麦生育期内的作物系物Kc和土壤水分胁迫系数Ks。

Estimating Field Evapotranspiration Using Soil Water Determined with Time Domain Reflectometry

The principles and methodology for measuring soil water content by time domain reflectometry (TDR) are described. Based on the determined soil moisture of different irrigation plots, the evapotranspiration (ET) of winter wheat is calculated with a field soil water budget model. The impact of the different insertion ways of TDR probes on measuring soil water storage and estimating ET is also discussed. According to the maximum passible ET values obtained in the fully-wetted root zone, actual ET under water stress root zone and ET of reference crop from meteorological data, the crop coefficient Kc and soil moisture stress factor Ks for various growth stages of winter wheat are calculated, respectively.