Soil Texture in Relation to Soil Organic Carbon and Nitrogen Contents in an Evergreen Broadleaved Forest in Kanghe Nature Reserve

A sampling plot of 4 hm2 evergreen broadleaved forest was set up in Kanghe Nature Reserve. Based on the content of 0.01 mm soil particles, three soil texture types, i.e., light loam, medium loam, heavy loam were grouped for the analysis of soil organic carbon, total nitrogen content and carbon-nitrogen ratio. The results showed that soil organic carbon content and total nitrogen content varied significantly as follows: heavy loam medium loam light loam. The maximum values of soil organic carbon content and total nitrogen content were 31.343, 1.882 g·kg-1, respectively, whereas the minimum values were 8.411, 0.621 g·kg-1, respectively. This study indicated that carbon and nitrogen content in the top soil layer exhibited spatial heterogeneity and the medium loam could represent the overall situation of soil carbon and nitrogen content of the entire sample. In addition, the organic carbon content and C/N had a significant difference(P0.05), while there was no significant difference between total nitrogen content under different soil texture. Soil organic carbon content and soil total nitrogen content had an extremely significant positive correlation(P0.01), with a correlation coefficient r = 0.8339, showing that the content of soil organic carbon under different soil texture had a high correlation to the total nitrogen content.