Abstract:

With incubation tests in laboratory,the mineralization of organic carbon in typical paddy soils in Changshu,Jiangsu Province,was investigated,meanwhile,the relationship between microbial biomass carbon,dissolved organic carbon and mineralization of organic carbon was also analyzed.Results showed that the content of soil organic carbon and total nitrogen in this region were 488～2731 and 058～284 g/kg，averaged in 1807 and 186 g/kg respectively.The content of microbial biomass carbon,nitrogen and dissolved organic carbon were 2940～1 2874,1854～8178 and 701～2879 mg/kg respectively,and were significantly 〖JP2〗different in different soil genus.The soil respiration intensity was 3476～19168 mgCO2/（kg·d），〖JP〗averaged in 79.93 mgCO2/（kg·d）.The sequence of respiration intensity in different soil genus was Wushan soil＞Wuhuangni soil＞Huihuangni soil＞White soil＞Huangni soil＞Wusha soil.The daily mineralization of soil organic carbon 〖JP2〗was between 1076～6520 mgCO2/kg,averaged in 4046 mgCO2/（kg·d）.〖JP〗The cumulative mineralization of soil organic carbon was 21525～1 30213 mgCO2/kg，averaged in 80720 mgCO2/kg,and the sequence of daily and cumulative mineralization was Wushan soil＞WuHuangni soil＞Wusha soil＞White soil＞Huihuangni soil＞Huangni soil.The rate of soil organic carbon mineralization in this region was 307%～758% and had no significant difference in different soil genus （〖WTBX〗p〖WTBZ〗＞005）.Statistical analysis showed that there existed positive liner relationship between respiration intensity,daily mineralization of soil organic carbon  and microbial biomass carbon,dissolved organic carbon,the correlative parameter were 0686，0594，0826，0749，respectively.〖