几种林木枯落物对糙率系数n值的影响  

The Effect of the Several Kind of Litters to the Roughness Coefficient

作　　者：张洪江[1] 北原曜[1] 远藤泰造 

机构地区：[1]北京林业大学,日本森林综合研究所

出　　处：《水土保持学报》1994年第4期4-10,共7页Journal of Soil and Water Conservation

摘　　要：该文对３种乔木树种枯落物和禾本科枯草的曼宁糙率系数ｎ值，分别进行了室内实验。在特定坡度和流量条件下，糙率系数ｎ值与４种枯落物量均呈现出指数相关关系。实验结果表明，不同树种枯落物对糙率系数ｎ值影响程度各异，其顺序从大到小依次为：杨属树种枯落物、刺槐枯落物、油松枯落物和禾本科枯草。如枯落物数量为０．２００ｇ／ｃｍ￣２（相当于２０ｔ／ｈｍ￣２）时，杨属树种、刺槐、油松枯落物和禾本科枯草的糙率系数ｎ值分别是：０．１９９５，０．１７８４，０．１２９７，０．０９９１。研究结果还表明枯落物量和枯草量的增加对糙率系数ｎ值的增大有一定限度，当单宽流量ｑ为９４ｍｌ／（ｍ．ｓ）时，枯落物量的上限值约为０．２５０～０．３００ｇ／ｃｍ￣２（相当于２５～３０ｔ／ｈｍ￣２）。In the laboratory,the effect of three kinds arbored litter and one kind of Poaceaewithered grasses to the value of roughness coefficient in the Manning Formula were studied.Theformulas of power relating between the value of roughness coefficient and the amount of the litterhave been gotten. The results show that the more litter,the higher value n is,and at the same con-ditions the effect order of litter to the roughness coefficient from higher to lower is Populus Linn.litter,Robinia Pseudoacacia Linn.litter,Pinus tabulaeformis Carr.litter and th Poaceae witheredgrasses.The roughness coefficient value of Populus Linn.litter is 0.1995,the roughness coefficientvalue of Robinia Pseudoocacia Linn. litter is 0.1784,the roughness coefficient value of Pinustabulae formis Carr. litter is 0.1297,and the roughness coefficient value of Poaceae withered grassesis 0.0991 while the amount of the litter is 0.200g / cm￣2(equal 20t/hm￣2).The result also shows thata limitation of increasing the roughness coefficient value exists by increasing the litter amount. Thetop limitation of the litter amotint is about 0.250～0. 300g /cm￣2(equal 25～30t/hm￣2)while the unitwidth flow is about 94ml(m.s).

关 键 词：林地 径流 糙率系数 枯落物 禾本科枯草 

分 类 号：S715.3[农业科学—林学]