土壤呼吸对秸秆与秸秆生物炭还田的响应及其微生物机制

土壤呼吸释放CO_2是温室气体排放的重要途径之一,减少土地利用中温室气体排放、增强土壤碳汇聚能力对于减缓全球温室效应具有重要意义。生物炭具有改善土壤理化性质、增加作物产量、调节土壤微生物性质等特性。本研究采用室外盆栽的方式,以地肤草为目标植物,研究了芦苇、水稻、互花米草三种农林秸秆及其秸秆生物炭还田对土壤的改良效应,以及对土壤呼吸的影响及其微生物机制。结果表明:秸秆及其秸秆生物炭均可改善土壤肥力,促进植物生长,且生物炭改良效果略好于秸秆直接还田。但秸秆生物炭还田的土壤呼吸显著低于秸秆直接还田,其中芦苇生物炭最低。秸秆直接还田可促进土壤β-糖苷酶、脱氢酶和活性微生物量等微生物活性指标,从而促进土壤呼吸,增加土壤CO_2的释放,而生物炭还田对土壤微生物活性无显著的促进作用,反而有一定的抑制作用,这可能是由于生物炭中易降解有机物含量很低,可降解性较低的缘故。

Response of soil respiration to straw and straw biochar returning and its microbial mechanism

Mineralization of soil organic carbon is one of the important ways to ouse greenhouse gas emissions in the land use and increasing soil carbon converge ability is of gas emissions （ CO2 ） , reducing great significance to slow down global warming. Biochar can improve soil physical and chemical properties, increase crop yield and regulate soil microbial ecology. This article adopted the way of outdoor pot experiment, elected kochia scoparia as grass plants, to study the improvement effects of reed, rice, smooth cordgrass straw and their biochar returning and its impact on soil respiration, carbon balance and its microbial mechanism. Results showed that straw and biochar could improve soil fertility and promote plant growth, and the improvement effect of biochar was slightly better. Soil respiration of straw biochar returning was significantly lower than that of straw returning directly, and reed straw biochar was the lowest. Straw returning directly could promote microbial activity indicators such as β-glyeosidase, dehydrogenase activity and soil microbial quantity, and enhance soil respiration as a consequence. But straw biochar returning had no significant role in promoting, but certain inhibition, which might be due to low content of straw biochar and its degradation-resistant.