宁南旱地连作春小麦产量动态与土壤干燥化效应模拟研究

Simulation of Yield and Soil Desiccation in Continuous Spring Wheat Field in Dryland of Southern Ningxia

为了解宁南旱区降水的变化特征，明确有利于土壤水分可持续利用的合理施肥水平，在数据库组建的基础上，应用WinEPIC模型定量模拟研究了宁南半干旱区固原和半干旱偏旱区海原1960～2000年期间不同肥力水平下连作春小麦的产量变化及其与深层土壤水分的关系。结果表明：（1）1960～2000年间宁南地区降水量呈波动性下降趋势；（2）宁南旱地连作春小麦产量以及麦田7m土层逐月土壤有效含水量均随降水量变化呈现波动性降低趋势。在模拟初期1～3年土壤干燥化趋势十分强烈，此后长期在较低水平上随降水量的变化而波动；（3）随肥力水平的提高和春小麦连作年限的延长，宁南旱地连作春小麦田土壤干层逐年加深和加厚，在6～11年后形成了相对稳定的土壤干层。固原连作春小麦适宜的施肥量范围为N60～90kg／ha和P2O530～45kg／ha，海原适宜的施肥范围为N0～60kg／ha和P2O5O～30kg／ha。

To provide scientific basis for sustainable development of local wheat production, to which fit the fertilization levels and soil water effect and adapt to precipitation condition in the dryland of Southern Ningxia as well as to be beneficial to soil water sustainable utilization. Based on model validation and databases establishment,the WinEPIC model was used to simulate yield and soil water effects of continuous spring wheat under different fertilization level treatments at Guyuan of semi-arid area and Haiyuan of semi-arid prone drought area in dryland of Southern Ningxia declined with fluctuation gradually. The simulated results showed：（1） The precipitation condition in the dry land of southern Ningxia declined with fluctuation gradually. （2） Grain yield and available soil water amounts in 0～7 m spil layers of spring wheat declined obviously with fluctuation, very strong soil desiccation on spring wheat farmland had occurred at the beginning of spring wheat growth simulations, and available soil water amounts fluctuated with precipitation changes for a long period at low level after soil desiccated. （3） Thickness and distributed as spring wheat growth years depth of desiccated soil layers on spring wheat field increased gradually increased and the level of fertilization improved improved, and stable desiccated soil layers occurred after 6～11 years of continuous cropping simulation. The amount ofsuitable fertilization level was N 60～90kg/ha,P2O5 30～45kg/ha at Guyuan,and N 0～60kg/ha,P2O5 30～45kg/ha.