Effects Of Manual Intervention To Community Characteristic And Soil And Water Conservation On Artificial Forest

The loose soil, crushing and slope steep terrain, low rainfall and the uneven season distribution, low vegetation coverage and other reasons caused serious soil and water loss and vulnerable ecological environment in Loess hilly region. Besides, the heavily vandalized is also the reason. All of these make the usage of the main land being obstructive and the economic development being slow. Therefore, the research of the soil and water conservation mechanism in different forest levels, and the relationship with the plantation community succession and soil and water conservation can help us to understand and evaluate the soil erosion problems in the comprehensive development of soil and water resources and to provide scientific theory basis for the rehabilitation of soil erosion.In this paper, taking Yi-chuan Pinus tabulaeformis artificial forest belts as research object, by using the farmland for control system, researches the original chinese pine, woodland without litter, clear land to find the surface soil erosion, runoff, sediment concentration and species diversity variation and features, obtained as follows main conclusions:(1)Along with the increase of rainfall, the interception of canopy and litters will increase monthly and seasonally. Among years, all the changes have the rule of high two low, but the interception rate is just in the opposite side, which has a trend of low two high. The stem flow is 2.5%; In artificial community's different growth stages, as the community's stand structure tends to be complete, the interception effect has been increasing.(2)Taking farmland as control system, the original chinese pine, woodland without litter, clear land have good soil and water conservation function, in which the original chinese pine forest with complete stand structure play the most significant role in nature, clear land to the secondary and woodland without litter to the last stage which shows that the litter is vital importance in the soil and water conservation.(3)During 1988 ~1991, rainfall and rainfall intensity were significantly correlated with sediment concentration in without litter land; during 1997 ~ 2000, after the stand structure being stable, there was no significant correlation between them; rainfall intensity negatively correlated with sediment concentration in original chinese pine and rainfall is negatively correlated with it in clear land; On the whole experiment, rainfall has notable correlation with runoff in original chinese pine land and clear land; in the farmland, the rainfall has no significant correlation with the sediment concentration; but the rainfall intensity and sediment concentration has significant correlation.(4)As the community succession, the diversity and richness of shrub will increase, and during different treatments, the diversity performances: Without litter land > original chinese pine land > clear land; Evenness is behaved for 1988 > 2010, without litter land > clear land > original chinese pine land. In three different treatments, the grasses diversity in artificially community performances: without litter land > clear land > original chinese pine land; in 1988, herb layer's evenness performances: without litter land > original chinese pine land > clear land, and the evenness of woodland without litter and original chinese pine land values nearly same; the herb layer evenness change rules in 2010 is similar to it in 1988; With the succession in artificial community, herb's richness increased, and herb evenness index 1988 > 2010.Thus,removed litter is more advantageous to the growth and renewal of the undergrowth in the good growing forest.