生物质炭和秸秆配合施用对土壤有机碳转化的影响

为探讨生物质炭和秸秆碳输入对土壤碳构成和转化的影响,通过室内培养试验,研究了单施生物质炭、秸秆及两者配合施入下土壤二氧化碳的释放特征以及土壤微生物碳和有机碳的变化.结果表明,秸秆有机碳在土壤中的矿化率为21.50%(2%添加水平),远大于等量生物质炭的矿化率(8.09%);施用等量(占4%土重)生物质炭和秸秆,培养200 d后土壤有机碳含量分别为24.40 g·kg~(-1)、17.40 g·kg~(-1),表明生物质炭对有机碳的提升作用大于秸秆的.施用生物质炭对土壤固有有机碳有一定的保护作用,生物质炭与秸秆配合施用促进了秸秆的矿化,对有机碳矿化影响的交互效应为正值.施用秸秆能大幅度增加土壤微生物碳,而生物质炭对土壤微生物碳影响小;秸秆和生物质炭配合也增加了土壤微生物碳,但其交互效应与培养时间、施用量等有关,可正可负.

Impacts of Biochar and Straw Application on Soil Organic Carbon Transformation

To explore the effects of biochar and straw application on soil carbon constitution and transformation, an incubation experiment was conducted to study the characteristics of the release of carbon dioxide,as well as the changes in microbial biomass carbon and organic carbon in soil after applying biochar or straw only, or biochar plus straw. The results showed that the straw mineralization rate of organic carbon in soil was 21.50% at 2% application level, which was much higher than that of biochar (8.09%). With the same addition amount of biochar and straw at 4% level for 200 days incubation, the soil organic carbon content was 24.40 and 17.40 g·kg^-1,respectively. It suggested that the positive impact of biochar application on improving soil organic carbon was greater than that of straw. The application of biochar had protective function on soil original organic carbon. Biochar promoted the straw mineralization and resulted in positive interaction effect between biochar and straw on mineralization of soil organic carbon. The application of straw increased soil microbial biomass carbon (MBC) greatly, while biochar had less impact on MBC. The application of straw and biochar also increased soil microbial biomass carbon, but the interaction effect could be positive or negative, which was dependent on the incubation time or application rate.