基于SIMDual_Kc模型估算非充分灌水条件下冬小麦蒸散量

为研究关中冬小麦植株蒸腾和土壤蒸发规律,利用2 a冬小麦小区控水试验实测数据,率定和验证了双作物系数SIMDual_Kc模型在关中地区的适用性.用大型称重式蒸渗仪的实测蒸散量值(或水量平衡法计算值)与模型模拟值进行对比.结果表明:SIMDualKc模型可较准确地模拟关中不同水分条件下冬小麦蒸散量,且模拟精度较高.模型估算的平均绝对误差为0.643 3 mm/d.模型估算的冬小麦初期、中期和后期的基础作物系数分别为0.35,1.30,0.20.另外,模型还可以较准确地估算不同水分供应条件下的土壤水分胁迫系数、土壤蒸发量和植株蒸散量.冬小麦整个生育期,土壤蒸发主要发生在作物生育前期,中期较低,后期略微增大;植株蒸腾主要发生在作物快速生长期和生长中期,整个生育期中呈先增大后减小的趋势.

Estimation of evapotranspiration of winter wheat under deficient irrigation based on SIMDual_Kc model

In order to estimate the evapotranspiration(ET),crop transpiration of winter wheat and soil evaporation in semiarid areas in Northwest China,a 2-year controlled irrigation experiment was conducted in the winter wheat field to calibrate and evaluate the SIMDual_Kc model for ET estimation in se-miarid regions.Evapotranspiration was observed by a large-scale weighing lysimeter or calculated by water balance approach,the observed evapotranspiration with the simulated ones was compared.The results show that the SIMDual_Kc model can accurately simulate the evapotranspiration of winter wheat under different irrigation treatments in Northwest China.The average absolute error is 0.6433 mm/d.The simulated value of basal crop coefficient for winter wheat at the initial-,mid-,and late-season growth stages is 0.35,1.3 and 0.2,respectively.In addition,the model can simulate the soil water stress,soil evaporation and crop transpiration accurately.During the whole winter wheat growing season,the soil evaporation mainly occurs in the early growth stage,decreases in midseason and slightly increases in late season.