Using Vensim to establish nitrogen dynamic simulation model and its validation in paddy field
利用Vensim建立水稻田氮素迁移动态模拟模型及其验证分析

The dynamic characteristics of nitrogen(N) absorption in rice,N variation in surface water and N leaching ways in paddy field under different N supply levels were studied in 2006 using a self-designed lysimeter with independent irrigation system arranged in the paddy field which was located in Fuyang and Hangzhou.Based on the former research results on the N transforming and moving features of soil-water-plant system in paddy field,a dynamic simulation model established using Vensim was compiled to simulate the conversion process of nitrogen in paddy field.The model was calibrated by data from the same N treatments field experiment conducted in Yuhang in 2003,and validated by the data observed in this experiment in 2006.The simulated result from the model fitted quite well with the observed data in Hangzhou and Fuyang experimental site.The result of independent t test between the observed data and the simulated data was P>0.05=0.581 in Hangzhou,and P>0.05=0.424 in Fuyang.There were significant correlations between the values predicted using the model and the actual ones.Model application and its fitness with actual value depend on the parameters calibration for N absorption,transforming and leaching.Further improvements need to be done for this model application on N dynamic prediction in paddy system.