The distribution characteristics of soil avalilable nitrogen and changing regularity of
species diversity of forest ecosystem
of Mt. Jinyun are studied. The results are as follows: ①Soil available nitrogen of dtheren conununities shows an evident gradient, i. e., A horizon(humus layer) > B horizon(deposit layer)> C horizon(parent material layer). There is very significantly and negatively correlations between soil available nitrogen and soil depth. ②Soil available nitrogen of A and B horizons increases along successional directions, i. e., shrub-grassland < Pinus massonia pure forest < P. massonta-Symplocos sethvenensis mixed forest < evergreen broadleaved forest. There is positively correlations between soil available nitrogen and the content of water, organic matter and litters thickness. ③
Species diversity indice orderly inereases with seral directions, but its fluctuations exist in shrub layer and grass layer. It shows different degree's correlations between the
content of available nitrogen of A, B horizons and species diversity indice.