Biochar amendment in soils has been proposed as an important strategy to improve soil C retention. However, while the exact roles of different biochar types on soil organic carbon (SOC) dynamics are not clear, the effect of their interactions with chemical fertilization on SOC, the dynamics of C-cycling enzyme activities and key C-cycling-related bacteria in rhizosphere soil remain unexplored. Therefore, biochars derived from rice straw, bamboo, cow, and pig manure were applied with/without chemical fertilizer to study soil C dynamics, the activities, diversity, and abundance of different C-cycling-related bacteria in the plant-soil system. Biochar + fertilizer (BF), irrespective of biochar source, induced an initial increase in dissolved organic and inorganic C (DOC and DIC) that were subsequently reduced compared to biochar over 15-weeks. Higher intensities of C-containing functional groups rather than the total C content of biochar induced the mineralization of SOC. Also, higher nutrient uptake, biomass, and CO₂ concentration in plants under BF had an insignificant influence on SOC. Similarly, the reduction in mineral-associated organic C, DOC, DIC, and invertase activity in BF soils was associated with a decrease in the relative abundance of some key C-cycling related bacterial orders: Gemmmatimonadales, Myxococcales, Nitrosomonadales, and Acidimicrobiales, while the hydrocarbon-degrading taxa (Sphingmonadales and Xanthomonadales), and N-cycling bacteria were stimulated. Hence, BF amendment could exert varied influences on C-cycling-related bacteria and on global C-cycling. The use of BF limited C-cycling and its loss by providing more N-substrates for N-cycling organisms, which also competed with most C-cycling-related bacteria for organic C to regulate C mineralization and its associated loss.

土壤中的生物炭改良剂已被提议作为改善土壤碳保持的重要策略。然而，虽然不同生物炭类型对土壤有机碳 (SOC) 动态的确切作用尚不清楚，但它们与化学施肥的相互作用对 SOC、C 循环酶活性和关键 C 循环相关细菌的动态影响根际土壤仍未开发。因此，从稻草、竹、牛和猪粪中提取的生物炭在有/无化肥的情况下应用，以研究土壤碳动态、植物-土壤系统中不同碳循环相关细菌的活性、多样性和丰度。无论生物炭来源如何，生物炭 + 肥料 (BF) 都会导致溶解的有机和无机碳（DOC 和 DIC）的初始增加，随后在 15 周内与生物炭相比有所减少。较高强度的含 C 官能团而不是生物炭的总 C 含量诱导了 SOC 的矿化。此外，更高的养分吸收、生物量和 COBF下植物中的₂浓度对SOC的影响不显着。同样，BF 土壤中矿物相关有机 C、DOC、DIC 和转化酶活性的降低与一些关键 C 循环相关细菌目数的相对丰度降低有关：Gemmmatimonadales、Myxococcales、Nitrosomonadales 和 Acidimicrobiales，而碳氢化合物降解类群（Sphingmonadales 和 Xanthomonadales）和 N 循环细菌受到刺激。因此，BF 修正可以对 C-循环相关细菌和全局 C-循环产生不同的影响。BF 的使用通过为 N 循环生物提供更多 N 底物来限制 C 循环及其损失，这也与大多数 C 循环相关细菌竞争有机 C 以调节 C 矿化及其相关损失。