Comparison of organic carbon pool of soil in bush and broad-leaved forests

In order to investigate the influence of bush growth on the forest soil‚the anthors analyzed the organic carbon pool and compared it with that of broad- leaved forests with the same environmental foctors．Soils at 0～20cm depth were collected as profile sample．The results show that soil microbial biomass carbon（MBC）and water-soluble organic carbon（WSOC） were much higher （P＜0∙01） in bush forest（0∙623and 0∙1 8 9g / kg） compared with the same values in broad- leaved forests（0∙338and 0∙148g/kg）．Higher percentages of MBC and WSOC to total organic carbon （TOC） were observed in bush forest（P＜0∙05）．However‚there were no differences in TOC and easily-oxidized organic carbon（EOC）‚soil enzymatic activities and soil nutrients to be found between the two types of forest．Both soil MBC and EOC were closely related（P＜0∙01） to TOC in the two forest stands．However‚a close relationship between WSOC and TOC was observed only in bush forest stand．It was found that soil total nitrogen（TN） in both forests were closely related to TOC（P＜0∙01）．The activities of sucrase‚protease‚urease and phosphatase were significantly（P＜0∙01） related to TOC‚MBC and EOC in the broad-leaved forest．The sucrase was the only enzyme which was well correlated to various fractions of organic carbon in bush forests．