利用Vensim建立水稻田氮素迁移动态模拟模型及其验证分析

Using Vensim to establish nitrogen dynamic simulation model and its validation in paddy field.

通过独立排灌系统的田间试验、自行设计的渗漏计研究在控水灌溉条件下大田不同氮肥水平的水稻氮素吸收、田面水氮素动态变化特征及氮素淋失规律.基于前人对氮素在稻田-作物-土壤及水体中的转化迁移途径的研究结果,用Vensim模拟软件构建稻田氮素迁移转化过程的动态模拟模型,利用2003年余杭农业科学研究所氮肥试验测定的相关数据对模型参数进行校验,再利用2006年富阳及杭州农业科学研究院实验数据验证模型的结构及动态.从对第1次及第2次施肥后植株吸氮量的模型模拟结果可以看出,杭州农业科学研究院与富阳的模拟结果数据都与实验数据相拟合,独立样本t检验结果为P>0.05=0.581及P>0.05=0.424.说明模型具有可应用性,但模型的拟合度与模型校准数据有很大相关,模型在具体应用上还有进一步改进的余地.

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.