Plant–microbial competition for amino acids depends on soil acidity and the microbial community

Purpose: Soil acidification influences competitive N uptake between plants and microorganisms. The mechanisms by which soil acidification affects competition between maize and microorganisms for organic N must be determined to understand N cycling and adjust the forms and levels of N fertilisation. Methods: The uptake of glycine, mineral N after glycine decomposition, and NH4+ by maize and microorganisms was investigated using 13C and 15N labelling. Microbial community composition biomarkers were analysed using phospholipid fatty acid (PLFA) analysis. Mineralisation of organic N was monitored via CO2 production, and gross NH4+/NO3− production and consumption was assessed using 15N pool dilution. Results: Soil acidification (pH from 7.6 to 5.1) increased the intact glycine uptake by maize roots (from 0.7 to 2.4% of added 15N) but decreased its uptake by microorganisms (from 32 to 2.4% of added 15N). Soil acidification altered the microbial community composition: the PLFA of arbuscular mycorrhizal fungi and anaerobes decreased by 6- and 1.5-fold, respectively. Soil acidification reduced the decomposition rates of proteins, peptides, and amino acids as indicated by the CO2 release. This corresponded to a gross NH4+ production increase by 1.3-fold and a gross NO3− production decrease by 97%, compared with soil at pH 7.1. Conclusions: Acidification led to decreased microbial biomass, shift in the microbial community, and the strong decrease (10–15-fold) in amino acid uptake by microorganisms, and was beneficial to maize plants, which assimilated 2.4% of the N added as glycine. However, these quantities of N are insufficient for a substantial increase in the N nutrition of the plants. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

Pan W.1, 2 , Tang S.1, 2 , Zhou J.1 , Liu M.1 , Xu M.1 , Kuzyakov Y. 3, 4, 5 , Ma Q.1, 2 , Wu L.1
Springer International Publishing
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  • 1 Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
  • 2 School of Natural Sciences, Bangor University, Gwynedd, LL57 2UW, United Kingdom
  • 3 Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Göttingen, Göttingen, 37077, Germany
  • 4 Peoples’ Friendship University of Russia (RUDN University), Moscow, 117198, Russian Federation
  • 5 Institute of Environmental Sciences, Kazan Federal University, Kazan, 420049, Russian Federation
Ключевые слова
Glycine transformation; Isotopic approach; Maize rhizosphere; Nutrient cycling; Organic nitrogen uptake; Plant–microbial competition; Rhizosphere microorganism
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