Sun Qiang, Yang Xu, Bao Zhengrong, Gao Jian, Meng Jun, Han Xiaori, Lan Yu, Liu Zunqi, Chen Wenfu
Postdoctoral Station of Agricultural Resources and Environment, Land and Environment College, Shenyang Agricultural University, Shenyang, China.
Key Laboratory of Biochar and Soil Improvement, Ministry of Agriculture and Rural Affairs, Shenyang, China.
Front Microbiol. 2022 Sep 23;13:967746. doi: 10.3389/fmicb.2022.967746. eCollection 2022.
Soil microbial organisms are conducive to SOC sequestration. However, little attention has been given to the contributions of living MBC and microbial necromass carbon to the SOC pool under biochar and straw amendments. The aims of the study were to explore (1) the effects of maize straw and biochar on MBC, POC, MAOC, DOC and microbial necromass carbon; (2) the contribution of MBC and microbial necromass carbon to the SOC pool; and (3) the relationships among the soil microbial community structure, microbial necromass carbon and other SOC fractions under maize straw and biochar application for nine consecutive years. Three treatments were studied: CK (applied chemical fertilizer only), BC (biochar applied annually at a rate of 2.625 t ha combined with chemical fertilizer), and SR (straw applied annually at a rate of 7.5 t ha). Both biochar and straw increased the SOC contents after nine successive maize plant seasons; the DOC and MAOC contents were also increased by biochar and straw amendments. Biochar had advantages in increasing POC contents compared to straw. Biochar and straw increased MBC contents by 48.54% and 60.83% compared to CK, respectively. Straw significantly increased the Galn, GluN, MurA, ManN and total amino contents ( < 0.05); however, biochar significantly increased the Galn and GluN contents ( < 0.05) but had no impact on the MurA contents and decreased the ManN contents. Biochar mainly increased the fungal-derived necromass carbon contents but had no effect on the bacterial-derived necromass carbon, and straw increased both the bacterial- and fungal-derived necromass carbon contents. Straw had no influence on the ratios of microbial necromass carbon accounting for SOC and MAOC, but biochar decreased the ratios in the current study. Similarly, biochar mainly increased the fungal PLFA and total PLFA contents compared to CK, but straw increased bacterial PLFAs, fungal PLFAs and Actinomycetes PLFAs. Maize yield were increased by 7.44 and 9.16% by biochar and straw application, respectively. These results indicate that biochar stimulates fungal activities and turnover to contribute to the stable soil carbon pool and that biochar also improves POC contents to improve the soil organic carbon sink.
土壤微生物有利于土壤有机碳的固存。然而，对于生物炭和秸秆改良条件下活性微生物量碳和微生物残体碳对土壤有机碳库的贡献关注较少。本研究的目的是探讨：（1）玉米秸秆和生物炭对微生物量碳、颗粒有机碳、矿物结合有机碳、溶解性有机碳和微生物残体碳的影响；（2）微生物量碳和微生物残体碳对土壤有机碳库的贡献；（3）连续九年施用玉米秸秆和生物炭后土壤微生物群落结构、微生物残体碳与其他土壤有机碳组分之间的关系。研究了三种处理：CK（仅施用化肥）、BC（每年以2.625吨/公顷的速率施用生物炭并配施化肥）和SR（每年以7.5吨/公顷的速率施用秸秆）。经过九个连续的玉米种植季节后，生物炭和秸秆均增加了土壤有机碳含量；生物炭和秸秆改良也提高了溶解性有机碳和矿物结合有机碳的含量。与秸秆相比，生物炭在增加颗粒有机碳含量方面具有优势。与CK相比，生物炭和秸秆分别使微生物量碳含量增加了48.54%和60.83%。秸秆显著增加了氨基葡萄糖、谷氨酸、MurA、甘露糖胺和总氨基酸含量（P<0.05）；然而，生物炭显著增加了氨基葡萄糖和谷氨酸含量（P<0.05），但对MurA含量没有影响，且降低了甘露糖胺含量。生物炭主要增加了真菌来源的残体碳含量，但对细菌来源的残体碳没有影响，而秸秆增加了细菌和真菌来源的残体碳含量。秸秆对微生物残体碳占土壤有机碳和矿物结合有机碳的比例没有影响，但在本研究中生物炭降低了这些比例。同样，与CK相比，生物炭主要增加了真菌磷脂脂肪酸和总磷脂脂肪酸含量，但秸秆增加了细菌磷脂脂肪酸、真菌磷脂脂肪酸和放线菌磷脂脂肪酸含量。施用生物炭和秸秆分别使玉米产量提高了7.44%和9.16%。这些结果表明，生物炭刺激真菌活动和周转，有助于稳定土壤碳库，并且生物炭还提高了颗粒有机碳含量，从而改善土壤有机碳汇。
