A field experiment was carried out to study the responses of soil respiration, soil C and N, composition of main microbial groups, enzyme activity, and microbial C source utilization to two organic amendments (i.e., straw and manure) added alone or combined with biochar for 9 months in an infertile soil. In comparison with the non-amended control, soil CO₂ emission rates were significantly increased following straw and manure addition, but they were decreased by 19% and 36% on average when co-applied with biochar. Organic amendments significantly increased the size of labile C pool by 21%, total phospholipid-fatty acid (PLFA) concentrations by 32%, activities of α-glucosidase by 51%, β-glucosidase by 115%, β-D-cellobiosidase by 105%, β-xylosidase by 43%, phenol oxidase by 59%, and peroxidase by 91% on average relative to the non-amended control, whereas biochar co-application with organic amendments had no effect on soil PLFA concentrations but significantly decreased the enzyme activities by 38% and the sizes of labile C and N pools by 16% on average. The results of the substrate-induced respiration confirmed a lower capacity of biochar-treated soils to use the C sources of carbohydrates and carboxylic acids. Structural equation modeling indicated that the response of soil CO₂ emission rates to organic amendment and biochar was directly linked to their effects on microbial activities. Therefore, our study demonstrated that biochar co-applied with straw or manure mitigated soil C loss by decreasing soil microbial activities.

通过田间试验研究了土壤呼吸、土壤碳氮、主要微生物群组成、酶活性和微生物碳源利用对单独添加或与生物炭混合添加的两种有机添加物（即秸秆和粪肥）的响应。在贫瘠的土壤中保存 9 个月。与未修正对照相比，土壤 CO ₂添加秸秆和粪便后，排放率显着增加，但与生物炭共同应用时，排放率平均下降了 19% 和 36%。有机添加物使不稳定 C 池的大小显着增加了 21%，总磷脂脂肪酸 (PLFA) 浓度增加了 32%，α-葡萄糖苷酶活性增加了 51%，β-葡萄糖苷酶活性增加了 115%，β-D-纤维二糖苷酶增加了 105 %，β-木糖苷酶增加 43%，酚氧化酶增加 59%，过氧化物酶增加 91%，相对于未修改的对照，而生物炭与有机改良剂的共同应用对土壤 PLFA 浓度没有影响，但显着降低了酶活性增加 38%，不稳定 C 和 N 池的大小平均增加 16%。底物诱导呼吸的结果证实了生物炭处理的土壤使用碳水化合物和羧酸的碳源的能力较低。结构方程模型表明土壤 CO₂有机改良剂和生物炭的排放率与其对微生物活动的影响直接相关。因此，我们的研究表明，生物炭与秸秆或粪便共同施用通过降低土壤微生物活动来减轻土壤碳损失。