黄土高原旱塬地冬小麦水分生产潜力与土壤水分动态的模拟研究

在EPIC模型介绍和模拟精度验证的基础上,利用EPIC模型对黄土高原旱塬地冬小麦水分生产潜力和土壤水分动态进行了中期(12a)和长期(30a)评价定量模拟研究。结果表明:(1)在12a实时气象条件下的模拟时段内,旱塬地小麦水分生产潜力随降水量变化呈现波动性降低趋势,3m土层土壤有效含水量也表现为剧烈波动性和逐渐下降趋势,土壤干燥化趋势明显;(2)在30a模拟气象条件下的模拟时段内,旱塬地小麦水分生产潜力呈现波动性轻微降低趋势,3m土层土壤有效含水量季节性和年际间波动性显著,但土壤干燥化趋势并不明显;(3)综合分析认为,在降水量减少幅度不显著的情况下,旱塬地麦田土壤干燥化只是一种短期现象,不会导致长期性土壤强烈干燥化现象发生,但产量随降水量变化的波动性不可避免。

Simulation of Water Potential Productivity of Winter Wheat and Soil Water Dynamics on Rainfed Highland of the Loess Plateau

Based on introduction,calibration and validation,the EPIC model was used to simulate water potential productivity (WPP) of winter wheat and soil water dynamics on rainfed highland at Changwu of the Loess Plateau for medium term (12 years) and long term (30 years) assessment simulation research respectively.The results show that:1)during the 12 year simulation period under real time weather conditions,WPP of winter wheat on rainfed highland fluctuates and decliness along with precipitation changes,crop available soil water amount in 3m soil layer also fluctuates and declines evidently,and trend of soil desiccation is remarkable;2)during 30 year simulation period under simulated weather conditions,WPP of winter wheat on rainfed highland fluctuates along with precipitation but declines slightly,crop available soil water amount in 3m soil layer fluctuates seasonally and annually,but without remarkable soil desiccation;and 3)after integrated analysis,it is thought that soil desiccation of wheat field on rainfed highland is a short time phenomenon and usually won't continue long if decline trend of precipitation is insignificant,but fluctuation of wheat yield along with precipitation change is inevitable.