重庆缙云山典型林分的坡面糙率系数及影响因素

Surface roughness coefficient and its influencing factors on the slope of typical forests in Jinyun mountain of Chongqing

根据2008年4月实测数据，以三峡库区重庆缙云山4种典型林分（马尾松纯林、马尾松阔叶混交林、常绿阔叶林和楠竹林）为研究对象，并以农耕地作对照，在野外径流小区实验的基础上，通过曼宁公式，对重庆缙云山林地坡面糙率系数n值进行研究。结果表明：地表糙率系数n值介于0.0079-0.2704之间，其中，马尾松纯林的糙率系数n值最小，马尾松阔叶混交林的糙率系数n值最大，大小排序为马尾松阔叶混交林〉阔叶林〉楠竹林〉马尾松纯林；糙率系数n（y）与枯落物厚度（x）的关系为Y=0.0205e^0.5436x，R^2=0.9237；地表水分渗透量（y）随着糙率系数n（x）增加而增大，其关系式为y=37.25lnx＋188.47，R^2=0.7782。

Surface roughness coefficients on the slope of forestland in Jinyun mountain of Chongqing by using the Manning Formula are conducted based on the measured field experiments data in 4 typical forests （Pinus massoniana, mixed with Pinus massoniana and broadteaf trees, broadleaf forest and Phyllostachys pubescens ）, compared to crop-land, in Jinyun mountain, Chongqing City of the Three Gorges Reservoin Area in April 2008. The results show that the values n of the surface roughness coefficient vary from 0.0079 to 0.2704. The value n of Pinus massoniana is minimum and the value n of the mixed with Pinus massoniana and broadleaf trees is maximum. The descending order of surface roughness coefficient of 4 typical forests is as follows： mixed with Pinus massoniana and broadleaf trees, broadleaf forest, PhyUostachys pubescens, Pinus massoniana. The relationships between surface roughness coefficient and litter depth is shown as linear relationship, the formula of surface roughness coefficient （y） and litter depth （x） is ：Y=0.0205e^0.5436x,R^2 is 0.9237 respectively, and there is a logarithmic relationship between surface roughness coefficient （x） and infiltration capacity of surface water （y）, the formula is： y = 37.25lnx ＋ 188.47, R^2 is 0.7782. The infiltration capacity of surface water increases with the increase of surface roughness coefficient.