Long‐term nitrogen fertilization decreases bacterial diversity and favors the growth of Actinobacteria and Proteobacteria in agro‐ecosystems across the globe

• Published in: Global change biology 2018-08, Vol.24 (8), p.3452-3461
• Main Authors: Dai, Zhongmin, Su, Weiqin, Chen, Huaihai, Barberán, Albert, Zhao, Haochun, Yu, Mengjie, Yu, Lu, Brookes, Philip C., Schadt, Christopher W., Chang, Scott X., Xu, Jianming
• Format: Article
• Language: English
• Subjects: Abundance; Acidic soils; Acidification; Acidobacteria; Actinobacteria; Agricultural ecosystems; Agriculture; agro-ecosystems; agroecosystems; anthropogenic activities; Anthropogenic factors; Bacteria; bacterial diversity; BASIC BIOLOGICAL SCIENCES; Biological fertilization; Communities; Community composition; community structure; Composition; Compound fertilizers; Crop yield; data collection; Ecosystem; Ecosystems; Fertilization; fertilizer rates; Fertilizers - analysis; Life history; meta-analysis; microbial biomass; microbial communities; Microbiota; Microorganisms; Mineral nutrients; N fertilization; Nitrogen; Nitrogen - analysis; nitrogen content; nitrogen fertilizers; NPK fertilizers; nutrient management; Organic carbon; Organic soils; pH effects; Phosphorus; Phosphorus - analysis; Potassium; Potassium - analysis; Proteobacteria; Relative abundance; Soil; Soil acidification; soil bacteria; Soil chemistry; Soil Microbiology; Soil microorganisms; soil organic carbon; Soil pH; Soil properties; Soil texture; Soil water; Soils; species diversity; Strategic management; Texture; Water management
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/gcb.14163

Long‐term elevated nitrogen (N) input from anthropogenic sources may cause soil acidification and decrease crop yield, yet the response of the belowground microbial community to long‐term N input alone or in combination with phosphorus (P) and potassium (K) is poorly understood. We explored the effect of long‐term N and NPK fertilization on soil bacterial diversity and community composition using meta‐analysis of a global dataset. Nitrogen fertilization decreased soil pH, and increased soil organic carbon (C) and available N contents. Bacterial taxonomic diversity was decreased by N fertilization alone, but was increased by NPK fertilization. The effect of N fertilization on bacterial diversity varied with soil texture and water management, but was independent of crop type or N application rate. Changes in bacterial diversity were positively related to both soil pH and organic C content under N fertilization alone, but only to soil organic C under NPK fertilization. Microbial biomass C decreased with decreasing bacterial diversity under long‐term N fertilization. Nitrogen fertilization increased the relative abundance of Proteobacteria and Actinobacteria, but reduced the abundance of Acidobacteria, consistent with the general life history strategy theory for bacteria. The positive correlation between N application rate and the relative abundance of Actinobacteria indicates that increased N availability favored the growth of Actinobacteria. This first global analysis of long‐term N and NPK fertilization that differentially affects bacterial diversity and community composition provides a reference for nutrient management strategies for maintaining belowground microbial diversity in agro‐ecosystems worldwide. This study explored the effects of long‐term N and NPK fertilization on soil bacterial community in agro‐ecosystems using a meta‐analysis of datasets across the globe. The long‐term N fertilization significantly decreased soil bacterial diversity, changed bacterial community composition, and favored the growth of Actinobacteria and Proteobacteria over Acidobacteria. The negative effect of N fertilization on bacterial diversity disappeared when N is coapplied with P and K. This study represents an important step forward for understanding the connection between elevated nutrient inputs, shifts in soil microbial communities, and altered ecosystem functioning.