Contrast Study On The Reproduction And Regeneration Of Robinia Pseudoacacia Plantation And Sophora Davidii Natural Community In Hilly-Gully Region Of The Loess Plateau

Soil erosion was serious, ecology environment was weak, diversity was decreased in hilly-gully region of the Loess plateau, which affect production and living of people's. Robinia pseudoacacia plantationin and Sophora davidii natural community in different habitats in hilly-gully region of the Loess plateau were studied systematical, including community diversity, effect of water, effect of environment factors, evaluated system of community regeneration was set up, fit habitat of R.pseudoacacia plantationin and S.davidii natural community was decided, in which theory were supplied standard for vegetable restore and rebuild in hilly-gully region of the Loess plateau.1. Age structure of population of R.pseudoacacia, effect of water in community, community diversity, effect of environment factors and regeneration were analysis: community diversity is lower cloudyslopeï¹¥lower sunnyslopeï¹¥upper cloudyslopeï¹¥upper sunnyslope; individual seeds quantity of R.pseudoacacia plantation is biggest in the lower cloudyslope (1140/tree); the asexual reproductive potential is lower cloudyslope(0.867)ï¹¥lower sunnyslope(0.808)ï¹¥upper cloudyslope(0.793)ï¹¥upper sunnyslope(0.444). R.pseudoacacia plantation in different habitat of the same aged stage had renewed seeding through the asexual reproduction in the lower cloudyslope, R.pseudoacacia plantationin in the lower cloudyslope of loess hilly region was a developing one, can survived for long. But there wse not renewed seeding in the mao slope and sunnyslope, water was serious shortage in mao slope and sunnyslope, which affect grow of R.pseudoacacia, So R.pseudoacacia was planted in lower cloudyslope and gully with better water condition, and effect foster measure was made.2. Age structure of community of S.davidii, effect of water in community, community diversity, effect of environment factors and regeneration were analysis: community diversity is lower sunnyslopeï¹¥lower cloudyslopeï¹¥upper sunnyslope; individual seeds quantity of S.davidii is lower sunnyslope(883/tree)ï¹¥upper sunnyslope(875/ tree)ï¹¥lower cloudyslope(746/ tree); the asexual reproductive potential is upper sunnyslope(0.722)ï¹¥lower sunnyslope(0.625)ï¹¥lower cloudyslope(0.444). S.davidii can natural renew well through the asexual reproduction in upper sunnyslope, individuals of middle aged were many, diversity was high, community was stability more and more, But renewed fewer seeding in the cloudyslope, although water was better incloudyslope, S.davidii was drought plant ,the effect of water is not big , So S.davidii community was planted in upper sunnyslope.3. Every comparation were analyzed: it was showed that S.davidii can reproduct and regenerate in hilly-gully region of the Loess plateau; R.pseudoacacia can reproduct and regenerate only in in lower cloudyslope and gully with better water condition, and to be the natural community, we must notice the effects of environment and foster measure.4. Local trees should be considered in priority in order to restore vegetable beneficial as soon as possible in recovering and rebuilding vegetable in the future in hilly-gully region of the Loess plateau; Natural community should be sealed and enabled coverage to raise gradually, at the same time, plants in herb layer should be not disturbed and promoted to develop ecology benefit. Man-made forest should be remade in order to emerge recession of community and forestation failure.