Simulation Of Water Productivity And Soil Desiccation Effects Of Artificial Grassland On Loess Plateau

It was found that soil desiccation is restricting artificial vegetation plantation day by day, and has became a serious hidden trouble of vegetations restoration during the study of vegetation restoration and soil water circulation. It is important for theory significance and production application to study water potential productivity and soil water using characteristic on the artificial pastures quantificationally, to explore the grass productivity change and the law of soil desicctation on artificial pasture, and to evaluate the stability of water productivity on different type artificial pasture on loess plateau.In this study, the method of actuarial investigation of forage productivity and soil moisture on artificial pasture combined with numerical simulation value by dynamic crop model were used. The investigated results of grass productivity and soil moisture on artificial pastures show that, the level of forage productivity on artificial pastures in semi-humid area, semiarid area, and semiarid prone drought area is compact with soil water and grass growth age. Soil desiccation has been occurring on all kind of pastures, and the degree of desiccation presents that it is worst in semiarid prone drought area, and worse in semiarid area, bad in semi-humid area. The daily weather, soil profile characteristic, crop growth parameter, tillage operations, fertilizer characteristic and cropping system databases of EPIC model on loess plateau were constructed. Based on EPIC model parameter modification, simulated effect validation on forage productivity and soil water amount of alfalfa and A. adsurgen pasture with actuarial measure values, the EPIC model were used to simulate forage productivity and root zone soil water change of alfalfa and A. adsurgen pasture at semi-humid area, semiarid area, semiarid prone drought area and north windy sandy area on loess plateau region for 10～30 year growth period, the water potential productivity and soil water change on artificial pasture were analyzed systematically. The conclusion show as followings:Based on parameter recension of EPIC model, the correlation coefficient between simulated alfalfa forage yield and root zone soil water with observed value were 0.8957 and 0.9884, the correlation coefficient between simulated A. adsurgen forage yield and root zone soil water with observed value were 0.714 and 0.9962, indicated that EPIC model could be applied to simulation study of artificial pasture on Loess plateau.