Understanding how reed-biochar application mitigates nitrogen losses in paddy soil: Insight into microbially-driven nitrogen dynamics

Yuping Zhang; Hang Zhao; Wang Hu; Yizhe Wang; Hanfeng Zhang; Xuan Zhou; Jiangchi Fei; Gongwen Luo

doi:10.1016/j.chemosphere.2022.133904

Understanding how reed-biochar application mitigates nitrogen losses in paddy soil: Insight into microbially-driven nitrogen dynamics

Chemosphere. 2022 May:295:133904. doi: 10.1016/j.chemosphere.2022.133904. Epub 2022 Feb 11.

Authors

Yuping Zhang¹, Hang Zhao¹, Wang Hu¹, Yizhe Wang¹, Hanfeng Zhang¹, Xuan Zhou², Jiangchi Fei¹, Gongwen Luo³

Affiliations

¹ College of Resources and Environment, Hunan Agricultural University, Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Changsha, 410128, China; National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Changsha, 410128, China.
² Institute of Soil and Fertilizer, Hunan Academy of Agricultural Sciences, Changsha, 410125, China.
³ College of Resources and Environment, Hunan Agricultural University, Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Changsha, 410128, China; National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Changsha, 410128, China; Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China. Electronic address: gongwenluo@hunau.edu.cn.

PMID: 35157877
DOI: 10.1016/j.chemosphere.2022.133904

Abstract

Biochar application to chemical-amended paddy soils has been proposed as a potential strategy to enhance nitrogen (N) retention and nitrogen use efficiency (NUE) by crops. However, optimal concentrations for these enhancements and the potential drivers are not well understood. Herein, a column-based pot experiment was carried out to investigate the impacts of reed-biochar application rate on N losses and dynamics in paddy soils treated by chemical fertilizer, and particularly, to explore the dominant factors of the processes. The addition of 2-4% reed-biochar had the most significant effects on mitigating N loss by leaching. Reed-biochar amendment increased soil total N and mineral N (NH₄⁺-N and NO₃^--N) content, and denitrifying gene abundance, and the increments of those variables were positively related to the application rate. Soil treated with 1-4% reed-biochar at harvest period showed higher gene abundances of ammonia-oxidizing and dissimilatory nitrate reduction to ammonium (DNRA) and higher activity of β-1,4-N-acetyl-glucosaminidase (NAG) and leucine aminopeptidase compared with the 4-8% application rate. The amoA-AOA gene abundance, NAG activity, and total carbon (C) content were the main predictors of total N and mineral N accumulated leakage. Total C content was the main predictor of soil total N and mineral N content, followed by the pH and NAG activity. These results suggest that adding 2-4% reed-biochar was more beneficial to mitigate N loss and thus enhance soil N storage and availability. This study highlights the importance of understanding how microbial populations mediate N transformation to decipher biochar-driven NUE enhancement in paddy soils.

Keywords: Extracellular enzyme; Functional population; Nitrogen dynamics; Nitrogen loss; Paddy soil; Reed biochar.

MeSH terms

Charcoal / chemistry
Fertilizers / analysis
Nitrogen* / analysis
Soil* / chemistry

Substances

Fertilizers
Soil
biochar
Charcoal
Nitrogen