Low-disturbance farming regenerates healthy deep soil toward sustainable agriculture-Evidence from long-term no-tillage with stover mulching in Mollisols
Low-disturbance farming regenerates healthy deep soil toward sustainable agriculture-Evidence from long-term no-tillage with stover mulching in Mollisols
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DOI：
10.1016/j.scitotenv.2022.153929
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发表时间：
2022-02-23
影响因子：
9.8
通讯作者：
Liang, Chao
中科院分区：
文献类型：
--
作者：
Deng, Fangbo;Wang, Hongjun;Liang, Chao
当前，全球农业发展正处于一个关键时期，因为它与人口增长，耕地退化和严重的环境问题相抗衡。尽管建议采用低干扰做法来改善土壤健康，但尚不清楚此类做法是否有利于关键的深层土壤功能。在这里，我们比较了3米深的土壤剖面中的土壤细菌群落和物理化学参数在中国东北黑土在休眠季节结束后，10年的耕作下，常规耕作无秸秆覆盖（CT），免耕无秸秆覆盖（NTNS），免耕秸秆覆盖（NTSM）。结果表明，与常规耕作相比，低干扰耕作（NTNS和NTSM）显著提高了土壤细菌的物种丰富度和多样性，丰富了潜在的代谢多样性。与传统耕作相比，免耕土壤细菌群落的垂直差异性降低，而秸秆覆盖土壤细菌群落的垂直差异性增加，表明免耕使土壤细菌群落的组成均匀化，而秸秆覆盖则增强了各层细菌群落组成的独特性。免耕秸秆覆盖显著提高了土壤含水量和根际有机碳（SEOC），降低了土壤pH值;土壤矿质氮含量随土层深度的增加而下降，在250-300 cm土层达到最大值，而在120-150 cm土层达到最大值。低干扰下0-150 cm土层矿质氮的积累可为作物提供更多的有效氮，而常规施肥下150-300 cm土层矿质氮的积累可能会渗入地下水。综上所述，我们的研究结果表明，低干扰的做法可以再生全土壤细菌多样性和潜在的功能，并促进根区的保水和持氮能力，从而减少氮肥的剂量，减轻氮污染的深层地下水，最终有助于农业可持续性在黑土区。
Currently, global agricultural development is in a critical period, as it contends with a growing population, degraded farmland, and serious environmental issues. Although low-disturbance practices are recommended to improve soil health, it is unclear whether such practices benefit critical deep soil functioning. Here, we compared the soil bacterial communities and physicochemical parameters across 3-m deep soil profiles in a Mollisol of Northeast China at the end of the dormant season after 10 years of farming under conventional tillage without stover mulching (CT), no-tillage without stover mulching (NTNS), and no-tillage with stover mulching (NTSM). We found that low-disturbance practices (NTNS and NTSM), compared with CT, evidently promoted soil bacterial species richness and diversity and enriched potential metabolic diversity. When compared to the bacterial communities in CT, the vertical dissimilarity of bacterial communities in NTNS decreased, while that in NTSM increased, indicating that no-tillage alone homogenized the composition of the bacterial community through soil depth profiles, but straw mulching enhanced the uniqueness of community composition at each layer. In comparison to CT, no-tillage with stover mulching significantly increased the soil water content and root-associated organic carbon (SEOC), and decreased soil pH. Mineral nitrogen declined with depth to 60 cm and then increased to its maximum at 250-300 cm under CT and at 120-150 cm under NTNS and NTSM. More mineral nitrogen at 0-150 cm under low-disturbance practices would provide more available nitrogen for crops in the coming growing season, while the accumulated nitrogen at 150-300 cm under CT may leach into the groundwater. Taken together, our results show that low-disturbance practices can regenerate whole-soil bacterial diversity and potential function, and promote water retention and nitrogen holding capacity within the root zone, thus reducing the dose of nitrogen fertilizer and mitigating nitrogen contamination to deep groundwater, ultimately contributing to agricultural sustainability in Mollisol regions.