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土壤水分及氮素淋失胁迫下根系吸水过程的模拟
李玉庆, 张 存, 张文贤
西藏农牧学院
摘要:
【目的】提出西藏高原农业种植区土壤水分亏缺、氮素淋失等因素耦合作用下的作物根系吸水胁迫响应函数,并基于Penman Monteith公式构建作物根系吸水模型。【方法】于2015年春青稞生育期,在江达灌区和西藏农牧学院农田水利实验场开展同步试验,测定灌区典型田块及实验室参照模式和常规模式下的春青稞根系吸水过程、土壤水分及NH+4-N和NO-3-N淋失过程,基于全局性最优方法率定了根系吸水模型参数,采用Nash-Sutcliffe系数和相对均方根误差对模拟精度进行检验。【结果】所构建的根系吸水模型可用于边界条件控制及土壤水分亏缺和氮素流失耦合作用下根系吸水胁迫响应关系的模拟,在春青稞全生育期内,模拟结果的Nash-Sutcliffe系数和相对均方根误差分别为0.74和0.050 8,生育阶段中Nash-Sutcliffe系数和相对均方根误差的最大模拟偏差分别为0.63和0.102。【结论】所提出的模型能够有效描述西藏高原农业种植区土壤水分亏缺和氮素淋失条件下的根系吸水过程,具有较高的模拟精度。
关键词:  水分亏缺  氮素淋失  根系吸水  动态响应  Penman-Monterith模型
DOI:
分类号:
基金项目:西藏自治区科技厅农牧业科技成果转化与示范项目“西藏农业面源污染调查与防控技术研究”;西藏自治区科技厅科技重大专项(Z2016C01G01/07);国家重点研发项目(2016YFC0402405);国家自然科学基金项目(51379152,91647109,51679257)
Simulation of root water uptake under stress of soil water deficit and nitrogen leaching
LI Yuqing, ZHANG Cun, ZHANG Wenxian
Abstract:
【Objective】In this study,a response function was proposed to describe the relationship between the actual and potential soil water uptakes under combined stress of soil water deficit and nitrogen leaching.A root water uptake model was also developed by incorporating the response function into the Penman-Monteith function.【Method】Field and controlled experiments were conducted in the Jiangda irrigation district and in the lysimeters located in the laboratory of irrigation and drainage,Xizang Agriculture and Animal Husbandry College,synchronously during the hulless barley growing period in 2015.The soil moisture content,NH+4-N and NO-3-N leaching,as well as evaporation and transpiration rates under normal and reference modes were monitored.The global optimization method was used to determine the model parameters.The Nash-Sutcliffe coefficient and relative root mean square error were used to evaluate the model performances.【Result】The model met the boundary conditions of soil water and nitrogen stress,and described the response of root water uptake to the combined stress of soil water deficit and nitrogen leaching.Good agreement was obtained between the simulated and measured root water uptakes.The Nash-Sutcliffe coefficient and the relative root mean square error were 0.74 and 0.050 8,respectively,during the hulless barley growing period.The minimum Nash-Sutcliffe coefficient and maximum relative root mean square error were 0.63 and 0.102,respectively.【Conclusion】The estimated model was suitable to describe root water uptake in the agricultural region in the Tibet Plateau under the combined stress of soil water deficit and nitrogen leaching.
Key words:  soil water deficit  nitrogen leaching  root water uptake  dynamic response  Penman-Monteith model