黄土高原半干旱区旱作农田土壤干燥化研究

Research on Soil Desiccation on Dry Farmland in Semi-arid Area of Loess Plateau

为了揭示黄土高原半干旱区旱作农田土壤干燥化发生规律,为黄土高原旱作农田土壤水分可持续利用和当地粮食生产的可持续发展提供科学依据,在黄土高原半干旱区固原、定西和海原3个有代表性的区域实地观测了不同类型旱作农田的深层土壤湿度,分析了旱作农田的土壤干燥化发生规律和土壤干层分布特征。结果表明:(1)黄土高原半干旱区固原、定西和海原各类农田0～600cm土层土壤湿度平均值分别为11.46%、14.37%、9.27%,各类农田土壤湿度均明显低于其土壤稳定湿度值,均发生了不同程度的土壤干燥化现象;(2)固原高产麦田和高产马铃薯田土壤干层厚度分别比低产农田土壤干层厚120cm和260cm;海原高产麦田和高产马铃薯田比低产农田土壤干层厚度厚20cm和80cm。黄土高原半干旱区随着旱作粮田产量的提高,农田深层土壤湿度逐渐降低,土壤干层逐渐加深和加厚。

Soil desiccation on dryland in semi-arid area of Loess Plateau was studied at Guyuan, Dingxi and Haiyuan. Soil moisture of dryland and the characteristics of desiccated soil layers were analyzed for high and stable yield as well as soil water sustainable utilization in dryland of semiarid area of Loess Plateau. The result showed that average soil moisture of 0-600 cm soil layers in various grain crop fields was 11.46%,14.37% and 9.27% respectively at Guyuan,Dingxi and Haiyuan. Soil desiccation had already happened at all kinds of grain crop fields. Moreover, soil moisture decreased, and thickness and distributed depth of desiccated soil layers in grain crop fields increased gradually,as grain crop yield increased in semi-arid area of Loess Plateau.