作物需水量模拟计算结果有效性检验

Validity examination of simulated results of crop water requirements

作物需水量是确定节水高效灌溉制度、制定灌溉排水规划和水资源合理配置必不可少的重要参数。当前模拟计算作物需水量的主要方法有FAO-56双作物系数法、双涌源能量守恒模型、根系层水量平衡模型和SWAP模型,而各种方法均有利弊和使用条件。不论采用哪种方法模拟计算作物需水量,其结果必须进行有效性检验,否则不能用于上述工程项目。该文用FAO-56双作物系数法基于灌溉试验数据模拟计算了人工牧草——老芒麦、冰草的需水量,并对模拟计算的需水量采用拟合相关图法、回归分析法和残差估计误差指示法进行了有效性检验。拟合相关图法属定性检验,给出了统计相关趋势;回归分析法和残差估计误差指示法为定量检验,给出了模拟计算值与实测值间的拟合优度和残差估计误差的范围。这种定性定量相结合的方法有效地检验了需水量模拟值与其实测值间的一致性,其结果可用于工程项目中。

Crop water requirement is very important parameter for making high efficient irrigation schedule,irrigation and drainage planning and scientific allocation of water resources.At present,the main approaches used for simulating crop water requirements include FAO-56 dual crop coefficient method,two source model of conservation of energy, water balance model of root zone and SWAP model.Each approach had its own advantages,disadvantages and applying conditions.No matter which approach is used for simulating crop water requirement,the validity of modeling results should be examined.Otherwise,the simulated crop water requirement could not be used for the engineering projects mentioned above.In the paper,based on irrigation experiments data,the crop water requirements of planted Elymus and Agropyron were simulated by the dual crop coefficient approach.Fitting correlation diagram method,regression analysis and indicating residual estimation errors were also used to examine the validity of simulated results.The first approach was a qualitative test method,and gave statistical correlation trend.Second and third approaches were quantitative test methods,and indicated the goodness of fitting and the ranges of the residual estimation errors.By integrating qualitative approach with the quantitative ones,the consistency between the simulated values and the observed values of crop water requirements was effectively examined,which the simulated results can be applied in the engineering projects.