还田秸秆分解与氮素释放的动态模拟

Simulation of Nitrogen Release from Decomposition of Straw Manure

还田秸秆的分解与氮素释放动态是作物养分管理的重要依据 ,建立了秸秆分解氮素释放动态的“整吞”式动态模拟模型。模型由秸秆有机质分解和残余有机质含氮率动态模拟两部分组成。有机质分解的温度效应用指数函数描述 ,水分效应用分段线性函数描述 ,用“标准天”反映温度与水分的综合影响。残余有机质含氮率动态变化用“标准天”为变量的函数模拟 ,初始秸秆含氮量与残余秸秆含氮量之差即为秸秆分解的氮素净释放。“整吞”式较之“吃馅饼”式建模构思 ,所需参数少且易通过实验获得 ,增加了模型的可用性。

The nitrogen release from the decomposition of straw manure is closely related to crop nutrition management. The effects of temperature and soil moisture on the decomposition of straw were described by using exponential functions and segmented linear functions respectively and their synthesized effects were described by “normalized days”. The concept of “whole swallowing” modeling structure was developed. In the new modeling structure, the forms and compositions of the organic materials changed with the process of decomposition and as a result, nitrogen concentrations in the straw residue were changed. The amount of released nitrogen was estimated by the difference in nitrogen content between the initial organic material and the residue. Because of its low parameter requirement and ease of parameter estimation through simple experiments, the developed simulation was more practical than de Vries's “pie eating” model structure. The validity of the models was tested using the experimental data in the seashore region of Jiangsu.