黄土高原半干旱区春小麦和春玉米产量动态与土壤干燥化效应模拟研究

Simulation of Grain Yield and Soil Desiccation of Spring Wheat and Corn Fields in Semi-Arid Area of Loess Plateau

为了寻求与黄土高原半干旱区降水状况相适应、有利于土壤水分可持续利用的大田作物及其合理的施肥水平,为当地粮食生产的可持续发展提供科学依据。在数据库组建的基础上,应用WinEPIC模型定量模拟研究了黄土高原半干旱区固原1960-2000年不同肥力水平下连作春玉米和春小麦产量变化和深层土壤水分效应。结果表明:(1)连作条件下春玉米和春小麦产量均随降水量呈现波动性降低趋势,产量波动性春玉米明显大于春小麦;(2)与连作春小麦相比,春玉米田0-7m土层土壤有效含水量较低,土壤干燥化速度较快;(3)随肥力水平的提高和作物连作年限的延长,农田土壤干层逐年加深和加厚,无肥、低肥、中肥、高肥处理下春玉米田土壤干层分别在连作第9年、第6年、第8年和第6年后分布于2-3,2-3,2-4,2-4m土层,春小麦田土壤干层分别在连作第11年、第8年、第6年和第8年后分布于2-3,2-3,2-3,2-4m土层,此后仅0-2m土层土壤湿度随降水量发生年际变化;(4)从产量稳定性、土壤干燥化程度和农田土壤水分可持续利用角度统筹考虑,固原旱地适宜于种植春小麦,适宜的施肥量范围为N60～90kg/hm2和P2O530～45kg/hm2。

To provide scientific basis for sustainable development of local crop production, that was fit for the fertilization levels and crop and adapt to precipitation condition of the dryland in semi-arid area of Loess Plateau as well as beneficial to soil water sustainable utilization. Based on model databases establishment, the WinEPIC model was used to simulate yield and soil water effects of continuous spring wheat under different level fertilization treatments at Guyuan of semi-arid area of Loess Plateau. The simulated results show as following. （1） Grain yield of the continuous spring wheat and corn decline along with rainfall changes, and spring corn yield volatility was higher than spring wheat. （2） Compared to spring wheat, available soil water amounts in 0--7 m soil layers of spring corn was lower, and soil desiccation speed was faster. （3）Thickness and distributed depth of desiccated soil layers on grain crop fields increased gradually as grain crops growth years and the level of fertilization. Distribution depth of desiccated soil layers of spring corn field was 2--3 m of no fertilization and low fertilization, 2--4 m of medium fertilization and high fertilization treatments after spring corn growth 9,6,8 and 6 years respectively. Distribution depth of desiccated soil layers of spring wheat field was 2--3 m of no fertilization, low fertilization and medium fertilization treatments, 2--4 m of high fertilization treatments after spring wheat growth 11,8,6 and 8 years respectively, then only 0--2 m layer of soil moisture with the annual changes in rainfall. （4） From the yield stability, perspective apply amou Into con the degree of soil desiccation and soil moisture in grain crop fields sustainable use sideration, spring wheat is appropriate to plant in Guyuan dryland, and its fertilization nts are N 60-90 kg/hm^2 and P2O5 30-45 kg/hm^2.