Site Condition Analysis And Underground Rhizome-root System Research Of Phyllostachys Nidularia Munro

The aim of this research was to examine the effects of site factors on the growth of Phyllostachys nidularia Munro in Liangping County, Chongqing and to study the structure of rhizome-root system to provide a scientific basis for transformation and manament of the Ph.nidularia forest.In this paper, aboveground biomass, underground rhizome-root system, site condition and the growth of Ph.nidularia were studied by statistics form subject of ecology, soil science and botany. The main results were as follows:1. Though a survey of 28 sample plots, the effects of 7 site factors on the aboveground biomass of Ph.nidularia were studied. The results showed that:The main site factors influencing the aboveground biomass of Ph.nidularia were in such order:slope degree, aspect, slope position, soil thickness, humus thickness, altitude and stone block content. ANOVA of aboveground biomass of Ph.nidularia and site factors showed that:aspect, slope degree, soil thickness and humus thickness had the significant effects on the aboveground biomass of Ph.nidularia. The altitude, slope position and content of stone block had influence on aboveground biomass of Ph.nidularia, but did not reach significant level. Ph.nidularia grows well on the sunny slope and the slowly varied slope with lower altitude, the soil thickness is more than 40 cm.2. The main component analysis of the altitude, aspect, slope degree, slope, soil thickness, stone block content, humus thickness, organic matter, total nitrogen and alkalization nitrogen of 28 sample plots in Liangping county, Chongqing showed that:the differentiation trend of types of site conditions of Ph.nidularia receives the accuse in soil fertility factor, the general configuration of the earth's surface factor and the morphological characteristics of site. The hill of Ph.nidularia was divided into four site types ofⅠ,Ⅱ,ⅢandⅣwith the method of cluster analysis. At Last, improvement measures for each site types were put forward basis on the analysis of the characteristics of site types and adapted to local conditions.3. Vsion layered mining and tracked rhizome, the rhizome and root system structure of Ph.nidularia was studied. The results show that:the relative rhizome age was well estimated according to the morphological character of rhizome; the total dry weight and length of rhizome of Ph.nidularia were 2.15kg·m-2 and 1.14m-m"2 respectively. The rhizome of Ph.nidularia are mainly distributed at a depth of 0-20 cm soil layer, accounting for about 88%. The rhizome at a depth of 20～40cm took a minor share, accounting for about12% and there were no rhizomes distributed at depths over 40cm of soil layer. The rhizomes in age class 4-6 years took the biggest share in terms of the age structure, accounting for about 65%,7～9 years old rhizomes accounted for about 20%,1-3 years old rhizomes took a minor share accounting for about11%. The total dry weight of the root was 1.63 kg·m-2. The roots were mainly distributed at the depth of 0～40cm in the soil layer and most were located in the 4 to 6 years old rhizome. Most of buds distributed at the rhizomes from 1 to 2 years old were the weak bud, accounting for 52.2%, the bud distributed at the rhizomes from 3 to 6 years old were mainly healthy bud, accounting for 46.9%, and 80.0% of buds at the rhizomes from 7 to 9 years old were empty bud. Therefore, better manament of the soil layer at 0～20cm depth, nurturing new rhizome, protecting healthy rhizome, weeding out old rhizome are good for the growth of rhizome and yield of shoots.