Liu Bangyan, Dai Yisha, Cheng Xin, He Xian, Bei Qicheng, Wang Yifan, Zhou Yuling, Zhu Bo, Zhang Kangping, Tian Xiaoqin, Duan Meichun, Xie Xiaoyu, Wang Longchang
College of Agronomy and Biotechnology, Southwest University, Chongqing, China.
Engineering Research Center of South Upland Agriculture, Ministry of Education, Southwest University, Chongqing, China.
Front Microbiol. 2023 Jul 18;14:1217966. doi: 10.3389/fmicb.2023.1217966. eCollection 2023.
This study was conducted to investigate the capability of the microbial community characteristics and soil variables to promote carbon and nitrogen cycles in maize fields under straw mulch. We covered the surface soil of the maize field with different amounts of wheat straw (0 kg/ha, 2,250 kg/ha, and 4,500 kg/ha) and used 16S rRNA and ITS sequencing, Biology ECO-plate, traditional enzymology, TOC analyzer, and HPLC to measure bacterial and fungal community composition and functions, characteristics of microbial carbon source metabolism, carbon and nitrogen fraction, enzyme activity, and organic acid content in the maize rhizosphere and non-rhizosphere. The results indicated that short-term straw mulch insignificantly affected the alpha diversity of bacterial and fungal communities whereas significantly influenced their beta diversity. The results of functional prediction revealed that straw mulch considerably boosted the relative abundances of bacteria belonging to chemoheterotrophy, aerobic chemoheterotrophy, ureolysis, and nitrogen fixation and inhibited fermentation and nitrate reduction in maize rhizosphere soil. These processes primarily drove the C and N cycles in soil. Straw mulch also improved fungal saprotrophs by raising the proportion of and . The Biology ECO-plate results illustrated that straw mulch weakened the metabolism capacity of microbial labile carbon resources. As a result, the labile C and N fractions were raised under straw mulch. Our results also showed that straw mulch primarily regulated the microbial community structure in rhizosphere soil by significantly decreasing and relative abundance while increasing . The fungal community structure is more than bacterial for affecting soil microbial biomass carbon, readily oxidizable organic carbon, dissolved organic carbon, available nitrogen, ammonium, and nitrate directly and indirectly through malic acid content and cellulase, protease, and amylase activity. Overall, our findings imply that straw mulch might influence the bacterial and fungal community structures, thereby boosting the production of labile C and N components and accelerating the C and N cycle in maize fields.
本研究旨在探讨秸秆覆盖下玉米田微生物群落特征和土壤变量促进碳氮循环的能力。我们用不同量的小麦秸秆（0 kg/ha、2250 kg/ha和4500 kg/ha）覆盖玉米田表层土壤，并使用16S rRNA和ITS测序、Biolog ECO平板、传统酶学方法、TOC分析仪和HPLC来测定玉米根际和非根际细菌和真菌群落组成及功能、微生物碳源代谢特征、碳氮组分、酶活性和有机酸含量。结果表明，短期秸秆覆盖对细菌和真菌群落的α多样性影响不显著，但对其β多样性有显著影响。功能预测结果显示，秸秆覆盖显著提高了玉米根际土壤中属于化学异养、有氧化学异养、尿素分解和固氮细菌的相对丰度，并抑制了发酵和硝酸盐还原。这些过程主要驱动了土壤中的碳氮循环。秸秆覆盖还通过提高 和 的比例改善了真菌腐生菌。Biolog ECO平板结果表明，秸秆覆盖削弱了微生物对不稳定碳资源的代谢能力。因此，秸秆覆盖下不稳定的碳氮组分增加。我们的结果还表明，秸秆覆盖主要通过显著降低 和 的相对丰度同时增加 来调节根际土壤微生物群落结构。真菌群落结构对土壤微生物生物量碳、易氧化有机碳、溶解有机碳、有效氮、铵和硝酸盐的影响比细菌群落结构更大，通过苹果酸含量以及纤维素酶、蛋白酶和淀粉酶活性直接或间接影响。总体而言，我们的研究结果表明，秸秆覆盖可能会影响细菌和真菌群落结构，从而增加不稳定碳氮组分的产生并加速玉米田的碳氮循环。
