The contrasting effects of biochar and straw on N2O emissions in the maize season in intensively farmed soil

• Published in: Environmental science and pollution research international 2021-06, Vol.28 (23), p.29806-29819
• Main Authors: Liu, Xingren, Tang, Zhanming, Zhang, Qingwen, Kong, Weidong
• Format: Article
• Language: English
• Subjects: Abundance; Agrochemicals; Ammonia; Ammonia-oxidizing bacteria; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; biochar; Carbon; Charcoal; China; Composition; Corn; Correlation; denitrifying microorganisms; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Fertilizer application; Fertilizers; Fluctuations; Flux; Genes; Growing season; microbial carbon; Microorganisms; mineral fertilizers; NirK protein; Nitrogen; Nitrosospira; Nitrous oxide; Oxidation; Research Article; Rhizobium; soil; Soil amendment; Soil conditions; Soil microorganisms; Soils; species; Straw; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-021-12722-2

This study evaluated the combined effects of biochar and straw on N 2 O flux and the community compositions of nitrifiers and denitrifiers in the maize season in an intensively farmed area in northern China. The experiment consisted of four treatments: (1) CK (only chemical fertilizer application); (2) C (biochar application); (3) SR (straw application to the field); and (4) C+SR (the application of both biochar and straw). The results indicated that during the maize growing season, N 2 O flux decreased by 30.3% in the C treatment and increased by 13.2% and 37.0% in the SR and C+SR treatments compared with CK, respectively. NO 3 − -N, NH 4 + -N, and microbial biomass carbon (MBC) were the main soil factors affecting N 2 O flux, and they were positively correlated with NO 3 − -N and negatively correlated with MBC in the C treatment and positively correlated with NH 4 + -N in the SR and C+SR treatments. Both biochar addition and straw return shifted the community compositions of nitrifiers and denitrifiers. N 2 O production was mainly reduced by promoting the ammonia-oxidizing bacteria (AOB) gene abundance and inhibiting the nirK gene abundance in the C treatment but promoted by inhibiting the AOB and nosZ gene abundances in the SR and C+SR treatments. Nitrosospira (AOB) and Rhizobium ( nirK ) were the main contributors among the treatments. NO 3 − -N, NH 4 + -N, and MBC were the main soil factors affecting the denitrifier communities. The predominant species associated with the nirK , nirS , and nosZ genes were positively correlated with NO 3 − -N and MBC and negatively correlated with NH 4 + -N. These results provide valuable information on the mechanism of N 2 O production and reduction in biochar- and straw-amended soil under field conditions.