黄土塬区不同土地利用方式土壤水分对次降雨的响应特征OA北大核心

[Objective]The aims of this study are to explore the response of soil water to rainfall,to reveal the soil water characteristics of different land use types in this area,and to provide observation basis for rainfall utilization and rational allocation of agricultural water resources in water shortage areas.[Methods]The soil water contents(SWC)of alfalfa field,fallow field,fertilized cropland(normal fertilization)and unfertilized cropland(no fertilization)of the loess tableland in 2021 were monitored.The effects of three rainfall events(greater than 30 mm)on soil water content were analyzed.[Results]With the increase of rainfall,the infiltration and water redistribution depths of alfalfa field,fallow field,fertilized cropland and unfertilized cropland also showed an increasing trend,and the maximum water infiltration depths were 340,500,500 and 500 cm,respectively.The SWC of different land use types had obvious seasonal characteristics,the monthly average SWC generally showed an increasing trend first and then decreased,the minimum values appeared in August,January,January and June,respectively,and the maximum values appeared in October.Soil water was still in the process of redistribution after the rainy season,the water redistribution depths of alfalfa field,fallow field,fertilized cropland and unfertilized cropland reached 400,700,800 and 700 cm,respectively,at the end of December.The change of soil water storage lagged behind rainfall,which was the strongest from September to October,the increase amounts of soil water storage in alfalfa field,fallow field,fertilized cropland and unfertilized cropland were 390.6,197.5,299.8 and 157.4 mm,respectively.[Conclusion]Among the four land use types,the soil water of alfalfa field with severe deficit was the most sensitive to rainfall.The maximum response depth could reach 400 cm,and the change range of soil water storage was also the largest.The process of water redistribution led to its change lagging behind precipitation.