基于SWAP模型的春玉米咸水非充分灌溉模拟

Simulation of deficit irrigation with saline water for spring maize based on SWAP model

为了探究甘肃省石羊河流域适宜春玉米生长的咸水非充分灌溉模式,应用SWAP模型模拟不同灌溉模式下的土壤水盐平衡、春玉米相对产量和相对水分利用效率,并预测了较长时期土壤水盐动态变化规律.研究结果表明:灌溉水矿化度为0.71 g/L和3.00 g/L的春玉米最优灌溉模式为生育期内灌4次水,灌溉定额均为408 mm,2种灌溉模式均能达到节约灌溉用水、提高作物产量和水分利用效率以及减少土体盐分累积量的目的.较长时期土壤水盐动态变化规律模拟结果表明:在冬灌条件下,春玉米最优灌溉模式下的土壤水分和盐分能够在模拟期内保持相对平稳的状态;在不同年份,相同土层土壤含水率随着土层深度的增加而增大,0.71 g/L的淡水灌溉土壤盐分主要累积在40~80 cm土层,3.00 g/L的微咸水灌溉土壤盐分主要累积在10~40 cm土层;5 a的模拟结果表明0.71 g/L和3.00 g/L的水持续灌溉5 a,不会引起土壤次生盐渍化.

In order to explore the appropriate management mode of deficit irrigation with saline water for spring maize growth in the Shiyang River Basin of Gansu province,the SWAP model was used to simulate soil water and salinity balance,relative spring maize yield and relative water use efficiency under different irrigation modes,and the long-term effects of soil water-salt dynamics were also predicted.The simulated results indicate that the optimal irrigation management mode for spring maize is to irrigate four times with total amount of 408 mm for irrigation water with 0.71 g/L and 3.00 g/L during the growing season of spring maize.The two irrigation modes can achieve the aim of saving irrigation water,improving crop yield and water use efficiency,and reducing the soil salt accumulation.The long-term simulation of soil water-salt dynamics indicates that the soil water content and soil salt content can remain relatively stable for the simulation period of time in the optimal irrigation mode of spring maize under winter irrigation.The soil water content increases with the increase of soil depth at the same soil layer in different years.The soil salt content mainly accumulates at the 40-80 cm soil layer under fresh water irrigation of 0.71 g/L and accumulates at the 10-40 cm soil layer under bracki-sh water irrigation of 3.00 g/L.Five-year simulation shows that the irrigation water with 0.71 g/L and 3.00 g/L will not result in soil secondary salinization.