Influence of Biochar Amendments on Decomposition of Soil Organic Carbon and Morphology of Heavy Metal in Red Paddy Soil
|School||Nanjing Agricultural College|
|Keywords||biochar soil organic C mineralization microbial biomass carbon and nitrogen δ13C heavy metal|
Biochar has well-developed pore structure, large surface area, negatively charged and more highly aromatase, and also has strong absorption capability and high degree of stability. Based on the above characteristics.adding biochar on soil properties and function has attracted increasing concerns, and become one of the hot research issues.Through sampling red paddy soils in Yingtan city of Jiangxi Province,laboratory incubation experiment were conducted to investigate the influences of biochar amendments on soil organic carbon (SOC) mineralization and microbial biomass carbon and nitrogen contents.Besides, the natural 13C abundance method was adopted to determine the changes of soil organic carbon decomposition after biochar amendments.Finally, fired biochar of different temperature were added to heavy metal contaminated soil,in order to graduate material carbon on pollution soil of improved effect. Results are as follows:The mineralization rate of SOC reached maximum at second day of incubation, decreased rapidly from 2nd to 7th day, and tended to stable afterwards. Throughout the 56 days of incubation.biochar amendments of 0.5% and 1.0% reduced cumulative mineralization of SOC by 10.0% and 10.8% respectively. In addition, applying biochar significantly increased contents of soil microbial biomass. Compared with the treatments without biochar, microbial biomass carbon and nitrogen contents in soil treated with 0.5% of biochar increased by 111.5～250.6% and 11.6～97.6%,microbial biomass carbon and nitrogen contents in soil treated with 1.0% of biochar increased by 58.9～243.6% and 55.9～110.4%,respectively.In the same treatments,microbial biomass contents in drought conditions (40% water-holding capacity) were higher than those in wet conditions (70% water-holding capacity).The results also indicated that biochar amendments of 0.5% and 1.0% decreased metabolic quotients by 2.4% and 26.8%, microbial quotients by 43～7% and 31.7%. respectively.After adding biochar in the red paddy soil to improve the soil organic carbon content and 813C value, and adding more content, this change more apparent.With the extension of incubation time.soil organic carbon content declinied, while the value’ofδ13C of soil was incressed. Joining of biochar has an impact on existing decomposition rate of organic carbon in soil.And such effect changing during the incubation period.Add 300℃firing of biochar processing in the early stsge (30d and 90d) slowed down the indegious organic carbon decomposition of the to mitigate the role of size and facilities into the content-related;in the latter period(180d) but for the organic carbon decomposition.400℃firing of biochar in the prophase (30d) of the original soil had no effect on the decomposition of organic carbon, in 90d when the slow decomposition of organic carbon in the original, late (180d) was to promote the decomposition of soil organic carbon.500℃firing of biochar in the prophase (30d and 90d) of the original soil had no effect on the decomposition of organic carbon, the latter (180d) was to promote the decomposition of soil organic carbon.The addition of biochar in a certain pollution red paddy soil has improvement effects. After adding biochar could significantly reduce the soil available Cu and Zn contents,and with the increase of the amount of biochar larger the decrease.Biomass burning temperature of carbon on copper contaminated soil improvement effect was different.