Comparative Study On Species Diversity And Soil Physical And Chemical Properties Of Different Age Castanopsis Hystrix Pure Plantation

This dissertation trying to reveal the change paterns of speices diversity and soil phsicaochemial properties between three different age Castanopsis hytrix pure panltation which is30age,16age and6age and different layer, both in time and space, the main results is shown as follows.(1)There is91species in both three age Castanopsis hytrix pure panltation which belong to47families and73genera. The species number in different layer is:shrub layer(48)> tree layer(44)> grass layer(17); the species number in different age is:6a(52)>6a(38)>30a(31).(2) The Margalef’ s species richness index, Shannon-Wiener index, and Simpson diversity index of tree layer rises with increasing stand age, which inversely with shrub and grass layer; the dominance index of tree layer drops with increasing stand age, which inversely with shrub and grass layer; the Pielou’s evenness index of tree layer is different in all three layers:tree layer is:30a>6a>16a; shrub layer is:6a>16a>30a; grass layer is:30a>16a>6a.(3)The difference of species diversity in shrub layer of different age Castanopsis hytrix pure panltation is extremely significant while not significant in grass layer.(4)The soil physical properties in different age Castanopsis hytrix pure panltation is:soil bulk density of surface(0-20cm) is lower than middle and deep layer, and the difference is significant in ages and layers; the soil capillary porosity decrease with the increase of soil depth in30a and6a, which inversely with16a; the soil non-capillary porosity decrease with the increase of stand age, the surface is bigger than middle layer and there is no pattern in deep layer; all four soil water index have a pattern that the content of soil water in surface is lager than middle and deep layer, in different age, soil moisture is30a>6a>16a, maximum moisture capacity, field capacity and capillaty capacity is6a>30a>16a。(5)The soil in experiment area is acid soil and becoming more and more acid with the increase of stand age. The trend of soil nutrition is different. There is no pattern in soil Oganic Carbon. The content of TN, AN, TP, AP, AK decrease with the increase of soil depth, the opposite of TK; the content of TK, AP, AK decrease with the increase of stand age, the rest is30a>6a>16a.(6)It is a complex change of soil hydrolysable nitrogen. For NH4+-N, in30a is surface<middle layer<deep layer, in16a is surface>middle layer>deep layer, in6a is surface> deep layer> middle layer. The change of NO3--N is as same as soil TN, surface<middle layer<deep layer.(7)The correlation of soil physical properties is significant or very significant, and it is different among soil chemical properties with no pattern. The correlation of soil chemical properties have no patterns, the pH has significant correlation with TN and NO3--N; The oganic carbon has no relationship with other indexes; TN has positive or significant correlation with TN and NO3--N, and in soil hydrolysable nitrogen, NH4+-N only has relationship with TP, NO3--N has positive correlation with TN, TP, AP; TP has positive correlation with AP, AP ha positive correlation with TN、NO3--N; TK has positive correlation with AK, and AP also has positive correlation with AP.(8)The correlation between shurb-grass layer and soil physical and chemical properties of different age Castanopisis hytrix is different. In16a and6a, Margalef’ s species richness index has correlation about soil N and P, meanwhile in30a, species diversity indexes has positive and significant correlation with soil water.