Pedosphere 31(4): 521--530, 2021
ISSN 1002-0160/CN 32-1315/P
©2021 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Bacterial communities in paddy soils changed by milk vetch as green manure: A study conducted across six provinces in South China
Songjuan GAO, ' target='_blank'>Weidong CAO, Guopeng ZHOU, Robert M. REES
1 College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China) 2 Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081 (China) 3 Scotland's Rural College (SRUC), West Mains Road, Edinburgh EH9 3JG (UK)
ABSTRACT
      The use of green manures contributes to sustainable soil and nutrient management in agriculture; however, the responses of soil microbial communities to different fertilization regimes at the regional scale are uncertain. A study was undertaken across multiple sites and years in Hunan, Jiangxi, Anhui, Henan, Hubei, and Fujian provinces of South China to investigate the effects of green manuring on the structure and function of soil bacterial communities in rice-green manure cropping systems. The study included four treatments:winter fallow with no chemical fertilizer as a control (NF), milk vetch as green manure without chemical fertilizer (GM), winter fallow and chemical fertilizer (CF), and a combination of chemical fertilizer and milk vetch (GMCF). Significant differences were found in the responses of soil microbial communities at different sites, with sampling sites explaining 72.33% (F=36.59, P=0.001) of the community composition variation. The bacterial communities in the soils from Anhui, Henan, and Hubei were broadly similar, while those from Hunan were distinctly different from other locations. The analysis of Weighted UniFrac distances showed that milk vetch changed soil microbial communities compared with winter fallow. Proteobacteria and Chloroflexi predominated in these paddy soils; however, the application of green manures increased the relative abundance of Actinobacteria. There was evidence showing that the functional microbes which play important roles in the cycling of soil carbon, nitrogen (N), and sulfur (S) changed after several years of milk vetch utilization (linear discriminant analysis score > 2). The abundance of methane-oxidizing bacteria and S-reducing bacteria increased, and microbes involved in N fixation, nitrification, and denitrification also increased in some provinces. We concluded that the application of milk vetch changed the bacterial community structure and affected the functional groups related to nutrient transformation in soils at a regional scale.
Key Words:  alpha diversity,bacterial composition,functional group,operational taxonomic unit,soil fertility,Weighted UniFrac distance
Citation: Gao S J, Cao W D, Zhou G P, Rees R M. 2021. Bacterial communities in paddy soils changed by milk vetch as green manure:A study conducted across six provinces in South China. Pedosphere. 31(4): 521-530.
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