黄土高原晋中半干旱区不同肥力水平下连作春玉米产量与土壤干燥化效应模拟

Simulation of yield and soil desiccation effects of continuous spring maize under different level fertilization treatments in Jinzhong semiarid areas of the Loess Plateau

在模拟精度验证基础上，应用WinEPIC模型模拟研究了黄土高原晋中半干旱区1960～2000年期间不同肥力水平下连作春玉米的产量变化和土壤水分效应。模拟结果表明：（1）无肥、低肥、中肥和高肥处理下连作春玉米的产量均呈现波动性降低趋势，其平均值分别为1．484、1．768、2．129和2．337t／hm^2；（2）4种肥力处理下连作玉米田逐月土壤有效含水量均呈现波动性降低趋势，平均每年分别减少5．6、8．4、8．4和11．4mm，不同肥力处理玉米田剧烈土壤干燥化过程和处理间差异的出现均主要发生在模拟研究的前5a内，无肥与低肥和中肥、高肥处理间土壤有效含水量差异十分显著；（3）在模拟初期出现了0～7m剖面土壤湿度逐年降低、土壤干层逐年加厚的干燥化过程，在模拟中后期均出现了稳定的土壤干层，无肥处理土壤干层分布于1～2m，低肥和中肥处理土壤干层分布于1～3m土层，高肥处理均分布于1～4m土层，表现出随肥力和作物产量水平的提高，土壤干层厚度逐渐加深；（4）晋中半干旱区玉米田土壤水分承载力介于低肥和中肥处理之间（1．868-2．154t／hm^2），相应的肥力水平为N45～90kg/hm^2。和P15～55kg／hm^2。

Based on model validation, the WinEPIC model was used to simulate yield and soil desiccation effects of continuous spring maize under different level fertilization treatments in Jinzhong semiarid areas of the Loess Plateau. The simulated results show as following： （ 1 ） Crop yield of continuous spring maize under no fertilization, low fertilization, medium fertilization and high fertilization treatment decreased significantly with fluctuation, and the average yield was 1. 484 t/hm^2, 1. 768 t/hm^2, 2. 129 t/hm^2 and 2. 337 t/hm^2 respectively; （2） Simulated monthly available soil water content of all 4 fertilization treatments declined with annual and seasonal fluctuations, and the average annual decreasing rate was 5.6 mm, 8.4 mm, 8.4 mm and 11.4 mm separately, and strong soil desiccation and differences of available soil water content among fertilization treatments occurred during the 5 beginning years of the simulation, and differences of soil water content among no fertilization, low fertilization and medium fertilization, as well as high fertilization treatments were very significant; （3） Soil moisture decreased and desiccated soil layers thickened gradually at the beginning of simulation, and stable desiccated soil layers occurred during middle and end of simulation. Distribution depth of desiccated soil layers was 1--2 m of no fertilization treatment, 1--3 m of both low and medium fertilization treatments, and 1--4 m of high fertilization treatments, and indicated that desiccated soil layers thickened with the increasing of fertilization and crop yield; （4） Soil water carrying capacity of dryland spring maize field at Jinzhong is 1. 868-2. 154 t/hm^2, and its fertilization application amount is N 45--60 kg/hm^2 and P 15--55 kg/hm^2.