Effect Of Biochar On Soil Microbial Biomass, Respiration And Community Structure

Biochar can ont only improve soil fertility,but also can serve as a carbon sink to mitigate the process of the greenhouse effect.In this study,three soils,e.g,a forest soil,a vegetable soil and a paddy soil,were amended with 0.2%,0.5%,1%,2%,5% biochar and the effect of biochar on soil microbial biomass,respiration and community structure was evaluated.The results are as follows:(1)Biochar has a significant impact on soil microbial biomass of the forest soil,the vegetable soil and the paddy soil. On the condition of uncultured state, TOC and TN values from fumigation or non-fumigation decreased with the increase of biochar concentration. Moreover, the difference also existed in the decreasing levels from different soils. Therefore, two methods were used to revise the measurements of soil microbial biomass. Solution 1:to eliminate the effect of biochar on determination, ratio of TOC value from biochar to that from non-biochar under uncultured state was determined. Then we used this ratio to revise each treatment from fumigation and non-fumigation on the condition of cultured sate. The same revision was applied to TN value. Solution 2:Ratio of microbial biomass value from biochar to that from non-biochar under uncultured state was measured. Then the ratio was used to revise each treatment from fumigation and non-fumigation on the condition of cultured state. The same revision was also applied to TN value. The combination of two solutions suggested that the linear relation between soil microbial biomass and total phospholipid fatty acid is more significant. Above all, solution 1 could be better at revealing the significant influence of biochar on soil microbial biomass. In a word, biochar can increase soil microbial biomass and the increment is positively correlated with biochar concentration.(2)Biochar can promote soil basal respiration.Biochar can exert greater effects in the forest soil and paddy soil than in the vegetable soil. Soil net mineralization and nitrification rates decreased with the amendment of biochar and the et mineralization and nitrification rates were forward to be negative in the higher biochar treatment.The result suggested that biochar can absorb soil ammonia nitrogen and nitrate.(3)Soil microbial community shifted with cultivation.Moreover,biochar had a significant effect on soil microbial community which was measured by PLFA method.