摘要
According to fixed-position data for 1992-2003 from 16 runoff plots of Caijiachuan watershed which lie in Jixian County, Shanxi Province, in the loess area, this paper studied the relationship between vegetation and runoff and sedimentproduction on slope lands. The results showed as follows: 1) Runoffand sediment production in Robinia pseudoacacia forestand Pinus tabulaeformis forest had a high correlation with precipitation amount and rainfall intensity, but the correlation decreased gradually with the increase of canopy density; 2) The secondary forest had better function of soil and water conservation than artificial R. pseudoacacia forest, and runoff and sedimentproduction in the former in an individual rain event was 65%-82% and 23%-92% lower than thosein the latter, respectively;3) The difference ofrunoff and sediment production in several land uses was very distinct. Runoff and sediment production in Ostryopsisdavidiana forest and the secondary forest were the least; runoff and sediment production in artificial R. pseudoacacia forest and P. tabulaeformis forest were 5-fold as much as those in O. davidiana forest. Besides, runoff and sediment production in mixed stand of apple trees and cropswere 16.14-fold and 2.96-fold higher than that in O. davidiana forest, respectively, but theamount decreased obviously after high-standard soil preparation for theformer;4) Based on gray correlation analysis of variousfactorsaffecting runoffand sedimentproduction on slope lands, it can be seen that stand canopy density and herb and litter biomass werethe most significant ones, whosegray correlation valuesall exceeded 0.6. Therefore, mixed forest with multi-layer stand structure and shrub forest should be developed in vegetation reconstruction of the loess area, which help to increase coverage and litter thicknessto cut down the runoffand sediment production dramatically on slope lands.
According to fixed-position data for 1992-2003 from 16 runoff plots of Caijiachuan watershed which lie in Jixian County, Shanxi Province, in the loess area, this paper studied the relationship between vegetation and runoff and sediment production on slope lands. The results showed as follows： 1） Runoff and sediment production in Robinia pseudoacacia forest and Pinus tabulaeformis forest had a high correlation with precipitation amount and rainfall intensity, but the correlation decreased gradually with the increase of canopy density; 2） The secondary forest had better function of soil and water conservation than artificial R. pseudoacacia forest, and runoff and sediment production in the former in an individual rain event was 65%-82% and 23%-92% lower than those in the latter, respectively; 3） The difference of runoff and sediment production in several land uses was very distinct. Runoff and sediment production in Ostryopsis davidiana forest and the secondary forest were the least; runoff and sediment production in artificial R. pseudoacacia forest and P. tabulaeformis forest were 5-fold as much as those in O. davidiana forest. Besides, runoff and sediment production in mixed stand of apple trees and crops were 16.14-fold and 2.96-fold higher than that in O. davidiana forest, respectively, but the amount decreased obviously after high-standard soil preparation for the former; 4） Based on gray correlation analysis of various factors affecting runoff and sediment production on slope lands, it can be seen that stand canopy density and herb and litter biomass were the most significant ones, whose gray correlation values all exceeded 0.6. Therefore, mixed forest with multi-layer stand structure and shrub forest should be developed in vegetation reconstruction of the loess area, which help to increase coverage and litter thickness to cut down the runoff and sediment production dramatically on slope lands.
基金
Funded by National Science and Technology Research Program for the Tenth Five-Year (No. 2001BA510B01).
关键词
黄土
植被
沉淀物
灰色关联
the loess area, vegetation, precipitation, runoff production, sediment production, gray correlation analysis
