Biochar-fertilizer interaction modifies N-sorption, enzyme activities and microbial functional abundance regulating nitrogen retention in rhizosphere soil

Muhammed Mustapha Ibrahim; Chenxiao Tong; Kun Hu; Biqing Zhou; Shihe Xing; Yanling Mao

doi:10.1016/j.scitotenv.2020.140065

Biochar-fertilizer interaction modifies N-sorption, enzyme activities and microbial functional abundance regulating nitrogen retention in rhizosphere soil

Sci Total Environ. 2020 Oct 15:739:140065. doi: 10.1016/j.scitotenv.2020.140065. Epub 2020 Jun 9.

Authors

Muhammed Mustapha Ibrahim¹, Chenxiao Tong², Kun Hu², Biqing Zhou², Shihe Xing², Yanling Mao³

Affiliations

¹ College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China; Key Research Laboratory of Soil Ecosystem Health and Regulation in Fujian Provincial University, Fuzhou 350002, Fujian Province, China; Department of Soil Science, University of Agriculture Makurdi, P.M.B, 2373, Makurdi, Nigeria.
² College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China; Key Research Laboratory of Soil Ecosystem Health and Regulation in Fujian Provincial University, Fuzhou 350002, Fujian Province, China.
³ College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China; Key Research Laboratory of Soil Ecosystem Health and Regulation in Fujian Provincial University, Fuzhou 350002, Fujian Province, China; Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China. Electronic address: fafum@126.com.

PMID: 32758953
DOI: 10.1016/j.scitotenv.2020.140065

Abstract

The impact of the excessive use of N fertilizer remains an environmental problem of global concern. The effect of biochar on soil N retention is still unclear, and knowledge on how a mixture of biochar and fertilizer (B-F) influence N-sorption, N-cycling enzymes activities, diversity and functional abundance of organisms regulating N-retention in rhizosphere soil is poorly understood. Therefore, biochars derived from bamboo, rice straw, cow and pig manure were characterized, and their interactions with NPK fertilizer were evaluated. Results showed that while the effect of biochar on N retention varied among biochar types, such variations increased after B-F. Unlike NH₄⁺ retention, NO₃^- retention by biochar in fertilized soil was poor (<8 weeks), but were however increased after longer periods (15 weeks) in B-F due to plant uptake, sorption and stimulation of N-cycling enzymes activities. This stimulation proved that N-fertilizer provided substrates for N-cycling organisms which was confirmed by the dominance of Proteobacteria, Chloroflexi, Actinobacteria, and Gemmatimonadetes which are important in soil N-cycling, despite the reductions in total diversity, class, phyla and genera abundance of bacterial 16SrRNA genes by B-F. This suggested that B-F induced specific organisms involved in N-cycling, which out-competed other organisms not involved in N-cycling. The provision of substrates by N-fertilizer in B-F for bacterial groups involved in N-cycling modified the rhizosphere microbial structure. The abundance of N-cycling organisms was regulated by the persistence among dominant groups, soil pH, total N, and microbial colonization induced by different biochars interacting with fertilizer which led to enhanced N-retention.

Keywords: Biochar; Enzymes; Fertilizer; Microbial community; Nitrogen.

MeSH terms

Animals
Cattle
Charcoal
Female
Fertilizers*
Nitrogen / analysis
Rhizosphere
Soil Microbiology
Soil*
Swine

Substances

Fertilizers
Soil
biochar
Charcoal
Nitrogen