Ecological water effect of returning orchard to cultivated land in apple base of gully region of the Loess Plateau
黄土高原沟壑区苹果基地退果还耕的生态水分效应

Recently, a lot of orchards in the gully region of the Loess Plateau have been degenerated, which should be returned to cultivated land. But the ecological water effect of returning orchard to cultivated land is still unclear. Taking the Wangdonggou watershed as a case study, this paper chose three land use types such as peak period orchard, waste orchard and cultivated land converted from orchard, the ecological water effects of returning orchard to cultivated land have been studied based on the soil moisture data of 1986, 2002 and 2009. The results show that: (1) The mean soil moisture content and water storage of wasted orchard and cultivated land converted from orchard are significantly bigger than those of the peak period orchard in 2009. With the orchard disuse or return to cultivated land, the soil moisture content will increase significantly. (2) When the land use changes from peak period orchard in 2002 to cultivated land in 2009, the mean soil moisture content of 200-600 cm profile of cultivated land converted from orchard is 10.62%, which is significantly bigger than that of the peak period orchard (8.53%). (3) Dried soil layer affected by biota use is a common soil water phenomenon in the peak period orchard, wasted orchard, and cultivated land converted from orchard, which is an urgent ecological problem that need to be resolved.