Estimation of nitrogen runoff loss from croplands in the Yangtze River Basin: A meta-analysis

Yufu Zhang; Hao Wu; Mengya Yao; Jia Zhou; Kaibin Wu; Minpeng Hu; Hong Shen; Dingjiang Chen

doi:10.1016/j.envpol.2020.116001

Estimation of nitrogen runoff loss from croplands in the Yangtze River Basin: A meta-analysis

Environ Pollut. 2021 Mar 1:272:116001. doi: 10.1016/j.envpol.2020.116001. Epub 2020 Nov 7.

Authors

Yufu Zhang¹, Hao Wu², Mengya Yao³, Jia Zhou³, Kaibin Wu³, Minpeng Hu³, Hong Shen², Dingjiang Chen⁴

Affiliations

¹ College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
² College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
³ College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Ministry of Education Key Laboratory of Environment Remediation and Ecological Health, Zhejiang University, Hangzhou, 310058, China.
⁴ College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Ministry of Education Key Laboratory of Environment Remediation and Ecological Health, Zhejiang University, Hangzhou, 310058, China. Electronic address: chendj@zju.edu.cn.

PMID: 33187836
DOI: 10.1016/j.envpol.2020.116001

Abstract

Nitrogen (N) runoff loss from croplands due to excessive anthropogenic N additions is a principal cause of non-point source water pollution worldwide. Quantitative knowledge of regional-scale N runoff loss from croplands is essential for developing sustainable agricultural N management and efficient water N pollution control strategies. This meta-analysis quantifies N runoff loss rates and identifies the primary factors regulating N runoff loss from uplands (n = 570) and paddy (n = 434) fields in the Yangtze River Basin (YRB). Results indicated that total N (TN) runoff loss rates from uplands and paddy fields consistently increased from upstream to downstream regions. Runoff depth, soil N content and fertilizer addition rate (chemical fertilizer + manure) were the major factors regulating variability of TN runoff loss from uplands, while runoff depth and fertilizer addition rate were the main controls for paddy fields. Multiple regression models incorporating these influencing factors effectively predicted TN runoff loss rates from uplands (calibration: R² = 0.60, n = 242; validation: R² = 0.55, n = 104) and paddy fields (calibration: R² = 0.70, n = 189; validation: R² = 0.85, n = 82). Models estimated total cropland TN runoff loss load in YRB of 0.54 (95% Cl: 0.23-1.33) Tg, with 0.30 (95% Cl: 0.15-0.56) Tg from uplands and 0.24 (95% Cl: 0.08-0.77) Tg from paddy fields in 2017. Guangxi, Jiangxi, Fujian, Hunan and Henan provinces within the YRB were identified as cropland TN runoff loss hotspots. Models predicted that TN runoff loss loads from croplands in YRB would decrease by 0.8-13.7% for five scenarios, with higher TN load reductions occurring from scenarios with decreased runoff amounts. Reducing upland TN runoff loss should focus primarily on soil N utilization and runoff management, while reducing N fertilizer addition and runoff provided the most sensitive strategies for paddy fields. Integrated management of water, soil and fertilizer is required to effectively reduce cropland N runoff loss.

Keywords: Agriculture; Nitrogen runoff loss; Paddy field; Spatial assessment; Water pollution; Yangtze river basin.

Publication types

Meta-Analysis

MeSH terms

Agriculture
China
Crops, Agricultural
Fertilizers
Nitrogen* / analysis
Oryza*
Phosphorus / analysis

Substances

Fertilizers
Phosphorus
Nitrogen