秸秆还田下小麦玉米周年N2O排放模拟模型研究

The object is to clarify the effect of straw returned on annual N2O emission and the quantitative relation of different factor, to study the annual efficient nitrogen use model in wheat and maize rotation system. Based on the nitrogen cycle process in the field, the N2O emission process in different straw returned will be simulated. By analyzing the spatial and temporal distribution of different nitrogen element in different soil level in different straw returned, the effect of straw returned on nitrogen movement and quantitative relation between nitrogen movement and N2O emission will be studied. By analyzing the water movement in different soil level in different straw returned, the effect of straw returned on water movement and quantitative relation between water movement and N2O emission will be studied. By analyzing the soil texture, soil organic carbon, pH in different straw returned, the effect of straw returned on soil factors and quantitative relation between the change of soil factors and N2O emission will be studied. Using the system analyse and simulation technique, the annual N2O emission simulation model in wheat and maize rotation and efficient nitrogen use model will be studied on the base of soil nutrient balance theory. We hope the result can provide the method and technique support for high yield and high efficiency in the wheat and maize rotation sysytem.

为明确不同秸秆还田量对小麦玉米周年土壤N2O的排放影响及各影响因素间的量化关系，探讨小麦玉米周年氮肥高效利用模式。本项目基于农田氮循环过程，以高产小麦夏玉米为研究对象，模拟不同秸秆还田量下农田N2O的排放动态。从不同秸秆还田量下土壤不同形态氮素含量的时空分布入手，探明秸秆还田量对土壤氮肥运移的影响，并量化其与N2O排放间的动态关联；从不同秸秆还田量下土壤不同层次水分的的变化动态入手，探明秸秆还田量对土壤水分运移的影响，并量化其与N2O排放间的动态关联；从不同秸秆还田量下土壤质地、有机碳、pH值等理化特性入手，探明秸秆还田量对不同土壤因子的影响，并量化其与N2O排放间的动态关联；同时在农田系统物质养分平衡理论的基础上，利用系统分析及模拟模型技术构建小麦玉米周年N2O排放模拟模型，研究小麦玉米氮肥高效利用模式。以期为我国小麦玉米轮作系统下的高产高效研究提供方法和技术支撑。

为明确不同秸秆还田量对小麦玉米周年农土壤N2O的排放影响及各影响因素间的量化关系，并构建其模拟模型。本课题在2015-2018年，基于农田氮循环过程，以高产小麦夏玉米为研究对象，通过不同的农田处理的对照，明确了秸秆还田量对土壤氮肥运移、土壤水分运移、土壤质地、有机碳、pH值等理化特性的影响，同时量化其与N2O排放间的动态关联。结果表明，秸秆还田显著促进土壤N2O排放，增加秸秆还田量，N2O排放通量明显的增加，但增加的幅度逐渐减小。除此之外，基于农田系统平衡的原理，从N2O排放影响因素角度出发，利用系统分析方法，构建小麦玉米周年农土壤N2O的排放模拟模型，并明确各模型参数及变量。研究结果表明，秸秆还田量对与N2O排放相关因素的影响存在明显差异并且规律明显，由此构建小麦玉米周年农土壤N2O的排放模拟模型是可行的。课题实施以来，共发表文章4篇。课题经费使用严格按照项目管理规定执行，支出清晰合理。