旱地覆膜栽培土壤水热硝酸盐耦合运移机制及模型模拟

项目名称： 旱地覆膜栽培土壤水热硝酸盐耦合运移机制及模型模拟

项目编号： No.41201279

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 地理学

项目作者： 蒋锐

作者单位： 西北农林科技大学

项目金额： 25万元

中文摘要： 黄土区旱地硝酸盐淋失造成土壤深层硝酸盐大量累积，不仅降低了氮肥的利用率，对环境也存在潜在的负面效应；覆膜栽培作为一项强烈影响土壤水热运动的耕作措施，对于黄土区粮食增产起到了积极的作用，而旱地覆膜栽培条件下土壤硝酸盐淋失的机理仍然不明。本研究以旱地覆膜栽培条件下土壤硝酸盐淋失为研究对象，将覆膜栽培作为水热因子，并将其与降雨量（水因子）、施肥量（肥因子）进行耦合，利用土壤剖面水分和温度监测设备及田间原位淋溶（渗漏）装置，通过田间定位监测、野外人工降雨实验及室内理化性质分析，系统研究水热肥耦合作用下农田硝酸盐累积与淋溶过程；结合模型模拟的方法，阐明覆膜栽培下土壤水热硝酸盐耦合运移机制，揭示水热肥耦合作用对硝酸盐淋溶的影响机理；估算硝酸盐淋失通量，评价覆膜栽培对旱地硝酸盐淋失的调控作用，为减少黄土区旱地硝酸盐淋失及其潜在负面环境效应，提高氮肥利用率提供科学依据。

中文关键词： 旱地；垄沟覆膜；硝酸盐；水热；Hydrus-2D

英文摘要： Nitrate leaching in drylands has led to nitrate accumulation in deep soil layer in loess area, which not only reduces Nitrogen use efficiency, but also shows the negative effects on environment. Plastic film mulch as a cultivation method which affects on soil water and heat significantly, has played an importantent role in improving food production in this drylands area, however, the mechanism of nitrate leaching under plastic flim mulch is poorly understood. Therefore, this study focuses on nitrate leaching under plastic film mulch in drylands, and takes plastic film mulch as the water-heat factor to couple with rainfall and fertilizer (water and fertilizer factors), to 1) investigate the integrated effects of soil water, heat and fertilizer on the processes of nitrate accumulation and leaching, by field observation using the soil profile moisture and temperature monitoring instruments and in situ leaching (percolating) devices, artifical rainfall experiment, and laboratory analysis; 2) clarify the coupling transport mechanism of soil water, heat and nitrate on the basis of field observation and model simulation; 3) calculate nitrate leaching flux and evaluate the regulatory effect of plastic film mulch on nitrate leaching. We anticipate this study will be useful for controlling nitrate leaching to reduce the n

英文关键词： drylands；mulching cultivation with ridge and furrow；nitrate；soil water and heat；Hydrus-2D