黄土高原沟壑区苹果基地退果还耕的生态水分效应

近年来,黄土高原沟壑区许多果园已经退化,需要重新退果还耕,但其生态水分效应尚不明了。以陕西长武县王东沟小流域典型果园为对象,选取了盛果期果园、退化果园和退果还耕等3种土地利用方式,分析1986、2002和2009年三期土壤水分数据,研究退化果园还耕的生态水分效应。结果表明:退化果园和退果还耕地的平均含水量和土壤储水量显著高于同期的盛果期果园。果园退化后废弃和退果还耕,土壤水分会得到部分恢复。当土地利用从盛果期果园变化为耕地后,在200~600cm土层,其土壤平均含水量(10.62%)显著高于盛果期果园(8.53%)。生物利用型土壤干层仍然是盛果期果园、退化果园和退果还耕地尚待急需解决的严重的生态问题。

Ecological water effect of returning orchard to cultivated land in apple base of gully region of the Loess Plateau

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.