黄土高原旱塬区高产玉米田土壤干燥化与产量波动趋势模拟研究

Simulation of soil desiccation and yield finctuation of high yield maize field on rain-fed highland of the Loess Plateau

为研究黄土高原旱作高产玉米田土壤干燥化与产量波动趋势,利用EPIC模型对黄土高原南部旱塬区玉米水分生产潜力和土壤水分动态进行中期(12a)和长期(30a)定量模拟研究。结果表明,在12a实时气象条件下的模拟时段内,旱塬地玉米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;在30a模拟气象条件下的模拟时段内,旱塬地玉米水分生产潜力呈现明显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剧烈,从长时段看土壤有效含水量呈现略微上升趋势;在降水量减少幅度不显著的情况下,旱塬玉米地土壤干燥化现象只是一种短期过程,通常不会导致长期性土壤强烈干燥化现象发生,但玉米产量随降水量变化的波动性不可避免。

In order to study the soil desiccation and yield fluctuation of high yield maize on Loess Plateau, the EPIC model was used to simulate water potential productivity（WPP）of spring maize and soil water dynamics on rain-fed highland at Changwu County of the Loess Plateau for a medium term （12 years） assessment and a long term（30 years）forecast simulated research. The results show that during 12-year real-time weather condition simulation period,WPP of spring maize on rain-fed highland fluctuates and declines along with precipitation changes, crop available soil water amount in 3m soil layer also fluctuates and declines evidently, and the trend of soil desiccation is remarkable. During 30-year simulated weather condition simulation period, WPP of spring maize on rain-fed highland fluctuates along with precipitation but declines slightly;crop available soil water amount in 3m soil layer fluctuates seasonally and annually,and has a light increase trend for a long term period. Soil desiccation of maize field on rain-fed highland is a short time phenomenon and usually does not last for long time if the declining trend of precipitation is not distinct, but the fluctuation of maize yield along with precipitation change is inevitable.