云南松侧根对浅层土体的水平牵引效应的初步研究  

PRELIMINARY STUDY OF TRACTIVE EFFECT OF LATERAL ROOTS OF PINUS YUNNANENSIS ON SHALLOW SOIL MASS

作　　者：周跃[1] 陈晓平[1] 李玉辉[2] 骆华松[2] 徐强[2] 

机构地区：[1]云南省地理研究所,昆明650223 [2]云南教育学院地理系,昆明650223

出　　处：《植物生态学报》1999年第5期458-465,共8页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金!4 92 0 1 0 0 3;4 9871 0 54;云南省应用基础研究基金!92 D0 80;98D0 0 7M;云南省科委主任基金! 97D0 0 6R;中

摘　　要：植物的侧根对周围土壤具有机械牵引作用。一般来讲 ,垂直根可以通过增加根际土层的抗剪强度来加固土体 ,斜向侧根则能够在对周围土体进行牵引固持的过程中 ,通过提高土体的水平抗张强度实现对土体的增强加固 ,这一作用即侧根的水平牵引效应。为了检验高山峡谷区云南松林是否也有这种效应 ,并调查其量值 ,我们在金沙江中上游的虎跳峡地区对云南松根际土层进行了直接剪土测试。结果表明 ,在表层土体中 ( 0～ 2 0 cm)松树侧根能在 1 0 0 0 cm2 的垂直横截面上提供 42 1 .1 9～ 561 .0 5N的水平牵引力 ,使土层的抗滑力提高 33.2 %～ 37.58%。受该牵引力的影响 ,侧根把根际土层的抗张强度提高了4.2～ 5.6k Pa。测试结果预示 ,只要云南松垂直根可以把浅层土体锚固到较深层稳定的土体上 ,通过水平牵引效应 ,云南松侧根可在一定程度上与垂直根共同克服林地浅层坡面的不稳定性 ,如浅层滑动和蠕移。Lateral roots of plants are provided with mechanical stabilizing effect on the rooted soil, through their tractive effect. In contrast to the effect of vertically extending roots, the traction effect reinforced the soil by enhancing the tensile strength of the rooted soil zone. To verify whether or not a tractive effect exists in the roots system of Yunnan pine forest ( Pinus yunnanensis ) in the Hutiaoxia Gorge, SW China, a direct in situ test was conducted at two sites in the gorge. The results show that, in the topmost soil (0～20cm), the lateral roots are able to provide a tractive force of up to 421 19～561 05N over a vertical cross section area of 20cm×50cm,or an increase in the pulling resistance of the rooted soil by 33 2～36 8%. This is equivalent to a tensile strength increase of the shallow rooted soil by 4 2～5 6kPa. The results imply that, together with the pine's vertical roots, the lateral roots of the pine trees, through their traction effect, are able to mitigate against shallow instability in the forested slopes, such as shallow slide and creep, at a certain degree.

关 键 词：云南松侧根 土壤侵蚀控制 水平牵引 

分 类 号：S159.257[农业科学—土壤学]