Cover crop residue diversity enhances microbial activity and biomass with additive effects on microbial structure
Cover crop residue diversity enhances microbial activity and biomass with additive effects on microbial structure
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DOI：
10.1101/2021.02.08.430214
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发表时间：
2021-02
期刊：
影响因子：
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通讯作者：
Xin Shu;Yiran Zou;L. Shaw;L. Todman;M. Tibbett;T. Sizmur
中科院分区：
文献类型：
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作者：
Xin Shu;Yiran Zou;L. Shaw;L. Todman;M. Tibbett;T. Sizmur
覆盖作物已被广泛用于农业生态系统，以提高土壤肥力和环境的可持续性。覆盖作物残体的分解会对地下群落及其活动产生进一步的影响，这对一系列土壤功能（例如，养分循环和有机物分解）。我们测试了一系列覆盖作物物种的植物残体对土壤微生物活性和群落组合的影响。我们预测，覆盖作物残留物会改变土壤微生物群落，更大的残留物的多样性将促进微生物的分解。在培养研究中，我们评估了作物残体多样性对微生物活性（土壤呼吸）的影响及其对微生物群落组成（PLFA）的影响。我们使用了四种覆盖作物残留物（荞麦，三叶草，向日葵和萝卜）的生物多样性混合物或每个物种的残留物的相等质量。覆盖作物残体的不同混合物的土壤呼吸速率显著（P < 0.05）高于四种单独残体的平均值，为57.61 µg C g−1 h−1，但土壤微生物生物量或微生物群落结构没有显著差异。这一发现可能归因于有机资源的更大多样性增加了生物化学小生境的数量，从而激活了休眠的微生物群落，以增加微生物活性，而不影响微生物生物量或群落组成。类似微生物生物量的更大呼吸表明，在更多样化的基质输入后，微生物活性可能更有效。这项研究证实了覆盖作物残留物对土壤微生物生物量和活性的积极影响，并强调覆盖作物残留物的混合物可能会提供超越单个覆盖作物残留物总和的增强土壤功能。
Cover crops have been widely used in agroecosystems to improve soil fertility and environmental sustainability. The decomposition of cover crop residues can have further effects on belowground communities and their activity, which is important for a series of soil functions (e.g., nutrient cycling and organic matter decomposition). We tested the effect of plant residues from a range of cover crop species on soil microbial activity and community assemblage. We predicted that cover crop residues would alter the soil microbial community and that a greater diversity of residues would enhance microbial decomposition. In an incubation study, we assessed the effect of crop residue diversity on microbial activity (soil respiration) and its consequent effects on microbial community composition (PLFA). We used either a biodiverse mixture of four cover crop residues (buckwheat, clover, sunflower and radish) or an equal mass of the residues of each of the individual species. The diverse mixture of cover crop residues had a significantly (P < 0.05) greater soil respiration rate, by 57.61 µg C g−1 h−1, than the average of the four individual residues, but did not have a significantly different soil microbial biomass or microbial community structure. This finding could be attributed to a greater diversity of organic resources increasing the number biochemical niches, and hence activating dormant microbial communities to increase microbial activity without affecting microbial biomass or community composition. Greater respiration from similar microbial biomasses suggests that microbial activity might be more efficient after a more diverse substrate input. This study confirms the positive impact of cover crop residues on soil microbial biomass and activity and highlights that mixtures of cover crop residues may deliver enhanced soil functions beyond the sum of individual cover crop residues.