Stochastic processes drive bacterial and fungal community assembly in sustainable intensive agricultural soils of Shanghai, China.

Shuangxi Li, Yujie Li, Cong Hu, Xianqing Zheng, Juanqin Zhang, Hanlin Zhang, Naling Bai, Haiyun Zhang, Minglu Tian, Songtao Ban, Guogan Wu, Aihu Pan, Peng Li, Weiguang Lv

The Science of the total environment 2021 Jul 15

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Sustainable intensive cropping systems have been implemented for three decades in suburban agricultural districts of Shanghai, China. These human-managed soils have been developed from paleosol or alluvial soils across different regions. However, little is known about the geographical distribution patterns of microbes and microbial community assembly in the sustainable intensive soils after decades of anthropogenic disturbances. Here, we investigated the impact of local geochemical properties and geographic distance on stochastic/deterministic microbial community assembly processes using high-throughput sequencing and phylogenetic null modeling analysis. Our results showed that soil pH was the most important environmental factor determining bacterial and fungal community structure. Importantly, only soil organic matter was positively correlated with fungal α-diversity, suggesting the efficient use of carbon substrates in sustainable agricultural systems, compensating for the lack of chemical fertilization and reduced tillage in these systems. Both bacterial and fungal communities had robust distance-decay patterns, but the rate of turnover of bacterial taxa was faster than that of fungi. Variation in bacterial and fungal communities was mostly attributed to the simultaneous effects of environmental variables and spatial factors. We also mapped the spatial distributions of the dominant bacterial and fungal taxa across the sustainable agricultural fields, making it possible to forecast the responses of agricultural ecosystems to anthropogenic disturbance. Based on the patterns of the β-nearest taxon index, this study demonstrated that stochastic processes shaped substantial bacterial and fungal community variation in sustainable intensive agricultural soils of the Shanghai suburbs. This variation may be attributed to the increasing microbial dispersal caused by hydrological connectivity in the agricultural fields or the release from environmental stress and weakened environmental filtering across the suitable pH range preferable for most soil microbes. These results unveil assembly mechanisms of soil microbial community after several decades of sustainable intensive management, and contribute to understand the role of microbes in ecosystems in establishing a functional equilibrium which may enable sustainability to be preserved. Copyright © 2021 Elsevier B.V. All rights reserved.

Citation

Shuangxi Li, Yujie Li, Cong Hu, Xianqing Zheng, Juanqin Zhang, Hanlin Zhang, Naling Bai, Haiyun Zhang, Minglu Tian, Songtao Ban, Guogan Wu, Aihu Pan, Peng Li, Weiguang Lv. Stochastic processes drive bacterial and fungal community assembly in sustainable intensive agricultural soils of Shanghai, China. The Science of the total environment. 2021 Jul 15;778:146021