太行山草被水土保持功能的研究

STUDIES ON THE WATER AND CIBSERVATION FUNCTIONS OF GRASS COVER IN TAIHANG MOUNTAINS

为了对太行山区草被类型的水土保持功能有个具体估价，通过人工降雨测定截留量，观察草被对降雨的截持和传导过程，调查枯落物量、土壤、根系等方法，对降雨从落到草丛至渗入土壤中的各个环节，分别进行了研究。结果表明，盖度７０％以上，以黄背草、白羊草为主的草被类型，当降雨达２０ｍｍ时，截留量已达饱和状态，总截留量为４．５６ｍｍ；雨滴经层层草叶的传导，到达地面时的动能近于０；枯落物量平均４．４５ｔ／ｈｍ２，可吸收降水０．８２７ｍｍ；０～５ｃｍ、５～１０ｃｍ、１０～１５ｃｍ土壤层的根系密度分别为３１、３３、２８条／１００ｃｍ２；非毛管孔隙度为３．２２％，渗透速度为４．０７ｍｍ／ｍｉｎ。草被的水保功能主要在于能消减雨滴动能，增加地面枯落物量，增强土壤的渗透力和抗蚀力。

The detailed processes of rainfall from reaching grass layer to penetrating into soilwere studied by measuring its interception，observing the holding and conduction in grasscover，and surveying litter amount,soil and root system etc. The resuIts showed that，with thecoverage of 70％,the interception of the grass cover type dominated by Themeda triandra var.japonica and Bothrtochtoa ischaemum was found saturated when the precipitation was 20mm.Its total interception was 4.56mm.The kinetic energy of rain drops when they reached groundwas about zero after going through the grass leaves.It could obsorb 0.827mm ofrainfall. Theroot densities of the various soil lavers of 0～5cm,5～10cm and 10～15cm were measured as31, 33 and 28 roots per 100cm2.The non-capillary porosity was 3.22％. The penetrating speedwas 4.07 mm／min. The functions of grass cover on soil and water conservation rely mainlyon diminishing kinetic energy of rain drops,increasing litter amount upon the soil surface，enhancing the penetrability and erosion-resistance of soil.