Simulated Crop Yield And Soil Water Within A Maize-winter Wheat-soybean Rotation In The Loess Plateau By APSIM

In order to improve the performance of APSIM(Agricultural Production Systems Simulator)in the Loess Plateau, a field experiment was conducted with a maize-wheat-soybean rotation system at Xifeng, Gansu during 2000 to 2005. The essential local parameters for APSIM were measured or collected. APSIM model was introduced to describe the component state within maize-winter wheat-soybean rotation system. APSIM simulated the dynamics of crop yield and soil water in the 0-200 cm soil layer within the rotation system. Results indicated that:(1): By using the modified parameter to simulate the wheat growth from 2001 to 2005 in the rotation system of maize-winter wheat-soybean. A higher correlation coefficient of 0.99 between APSIM predicted grain yield and measured value was obtained. The correlation coefficient between APSIM predicted total biomass and the measured value was 0.8467. Model also sensitively captured the effects of heavy rainfall and delay planting on wheat growth in 2003. The simulated results show that the parameters of the local species such as the various stages of temperature, solar energy utilization efficiency, the role of jarovization, the biggest filling rate, radiation use efficiency, water use efficiency, stubble surface parameters was valid.(2): Base on the experimental data, APSIM maize module simulate the maize growth. The correlation coefficient between APSIM predicted total biomass and the measured value was 0.8319. The correlation coefficient between APSIM predicted grain yield and the measured value was 0.7023. The predicted value was generally lower than the measured value. The total biomass and grain yield performed closest fitness in drought period. APSIM maize module can largely reflects the dynamics of crop yield in the Loess Plateau. However, further study will be required to improve the performance of APSIM wheat module in the Qingyang Loess Plateau.(3):APSIM soybean module didn't preformed as well as it was expected. The correlation coefficient between APSIM predicted total biomass and the measured value was 0.4824.The correlation coefficient between APSIM predicted grain yield and the measured value was 0.4824. APSIM soybean module need further study to improve the performance of the parameters for APSIM soybean module's local use.(4):The simulation for soil water dynamics by APSIM was good. The correlation coefficient between APSIM predicted value and the measured value for T treatment and TS treatment were 0.8249 and 0.8326 respectively. The correlation coefficient between APSIM predicted value and the measured value for NT treatment and NTS treatment were 0.8066 and 0.768 respectively. The predicted value was a little lower than measured value. It still need to be adjust parameters to further improve the performance.At present, Results indicated that the modified parameters for primarily application APSIM in Qingyang Loess Plateau, China has perspective potential. However, following up study for APSIM module still be required to improve the performance of APSIM in the Qingyang Loess Plateau. The application of other crops model in APSIM still require further study.