黄淮海平原冬小麦生长期土壤水氮利用效率模拟分析

 【目的】以黄淮海平原为研究区域，采用基于地理信息系统（GIS）的模拟模型对区域农田土壤水氮行为进行模拟和评价。【方法】建立和验证土壤水、热、氮和作物生长联合模型并与GIS相结合，在1999～2000年黄淮海平原的农村社会经济和土壤、气候等条件背景下，对冬小麦生长期土壤水氮利用效率和氮素损失量的区域分布规律进行分析。【结果】区域模拟结果表明，水分利用效率(WUE)、氮素利用效率(NUE)及土壤氮素淋失情况的空间分布在各地貌区之间有明显差异。多元线性逐步回归分析表明，1 m土体的氮素淋失量与灌水和降水量、施氮量、土壤饱和导水率（Ks）呈极显著的正相关；WUE与施氮量和日照时数呈极显著的正相关，而与降水和灌水量、Ks呈极显著的负相关；NUE与降水和灌水量、日照时数呈极显著的正相关，与施氮量、Ks呈极显著的负相关。【结论】黄淮海平原区域农田土壤水氮行为受自然条件和农田管理措施的显著影响，其空间分布规律可利用基于GIS的过程模型进行模拟和评价。

Simulation and Analysis of Soil Water and Nitrogen Behaviors in Winter Wheat-Growing Season in Huang-Huai-Hai Plain

【Objective】The Huang-Huai-Hai Plain(HHHP) was selected as the research region in this paper. Regional soil water and nitrogen behaviors were simulated and evaluated by a geographic information system (GIS) based conjunctive simulation model.【Method】 A conjunctive model incoporating soil water, heat, nitrogen behaviors and crop growth was established and validated and then coupled with GIS. The regional distribution of water and nitrogen use efficiency (WUE and NUE), nitrogen loss were studied under the soil, meteorological and rural socio-economical conditions of HHHP from 1999 to 2000 by the GIS-based model.【Result】The inter-physiognomy variations on WUE, NUE as well as soil nitrogen leaching has exhibited significant differences. The multivariate stepwise regression results show that in winter wheat-growing season, nitrogen leaching was significantly positively correlated with nitrogen fertilizer applied (NFA), saturated hydraulic conductivity (Ks) and rainfall and irrigation amount (RIA). WUE was significantly positively correlated with nitrogen fertilizer applied and sunshine hours (SH) and significantly negatively correlated with RIA and Ks. NUE was significantly positively correlated with RIA and SH and significantly negatively correlated with NFA and Ks. 【Conclusion】The regional soil water and nitrogen behaviors of HHHP were affected by the biophysical conditions and farming practices obviously, and their spatial distribution can be simulated and evaluated by the GIS based process model.