黄土坡耕地弃耕后土壤入渗变化规律及影响因素

Study on beginning infiltration law of the being wild soil in loess plateau

黄土高原的土壤侵蚀十分严重,退耕还林是我国在黄土高原推行的水土保持政策。研究弃耕前后土壤入渗的差异,不仅可以为黄土高原实施退耕提供理论指导,同时还可以为退化土壤的修复提供理论依据。本文通过人工模拟降雨,研究了坡耕地弃耕后不同年限的土壤初始入渗的变化规律,分别采用四种处理方法(保留地上草被,除去地上草被,除去结皮,翻耕)对弃耕地进行处理,得出初始入渗过程中,弃耕地入渗能力随年限逐渐恢复;撂荒一、两年的弃耕地受结皮减渗作用影响大;随着弃耕时间的增长,生物结皮减渗作用开始小于地上草被的增渗作用;撂荒12年时,结皮和地上草被都开始起到增渗作用。

The soil erosion in the loess plateau is very severe. Returning farmland of controlling water and soil in the loess plateau. Study on moisture cycle in soil to forestland is the Chinese policy before and after the returning will not only bring academic direction to the returning in the loess plateau, but also provide academic basis for repairing the returned soil. By using rain simulator, the beginning infiltration law of soil with different landform and different being wild years is investigated. The four disposing ways used in the paper are keeping upper grass, cuting upper grass, keeping biologic curst and ploughing. During the whole beginning 10 minutes infiltration period, the infiltration ability of returned land resumes with the returning years. For the land with one or two returning years, the upper grass increases the infiltration, but the biologic crust decreases the infiltration, and the decreased infiltration by the crust is more than the increase by grass. With the increase of returning years, the increased infiltration by upper grass begins to exceed the decreased filtration by the crust. To the 12 returning years, both the crust and the grass begin to increase the infiltration.