Spatiotemporal characteristics and driven forces of nitrogen flow of dairy farms in China: Based on a comprehensive model combined with production practices and embedding localized parameters

Xiao Yang; Lijie Zhang; Chaoyuan Wang; Buchun Si; Weizhong Jiang; Chao Liang; Zhengxiang Shi

doi:10.1016/j.scitotenv.2024.177464

Spatiotemporal characteristics and driven forces of nitrogen flow of dairy farms in China: Based on a comprehensive model combined with production practices and embedding localized parameters

Sci Total Environ. 2024 Nov 18:957:177464. doi: 10.1016/j.scitotenv.2024.177464. Online ahead of print.

Authors

Xiao Yang¹, Lijie Zhang¹, Chaoyuan Wang², Buchun Si³, Weizhong Jiang³, Chao Liang³, Zhengxiang Shi³

Affiliations

¹ College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China.
² College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture and Rural Affairs, Beijing 100083, China. Electronic address: gotowchy@cau.edu.cn.
³ College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.

PMID: 39542276
DOI: 10.1016/j.scitotenv.2024.177464

Abstract

This study developed a comprehensive nitrogen (N) flow model utilizing localized data in 2000-2019. Enhancements were conducted upon previous models: (1) variations in feed N intake of cows across different production phases was considered; (2) N emission in the Intergovernmental Panel on Climate Change (IPCC) and the European Monitoring and Evaluation Program and the European Environment Agency (EMEP/EEA) was incorporated; (3) emission factor (EF) of NH₃ was corrected based on local climate; and (4) field application of manure was excluded from the system boundary to accommodate China's production status. The effects of farm scale (LF, ≥100 heads; SF, <100 heads) and manure management strategies (dry-cleaning and slurry) were considered. Twelve indicators regarding nitrogen use efficiency (NUE), N emission and N losses were identified to assess the spatiotemporal dynamics of N flow. Sensitivity analysis was performed on NUE and N emission. The efficacy of N management practices was evaluated through simulating 2050 scenarios, which included business as usual (BAU), improved cow productivity (DPI), and manure management building on DPI (FMI). It demonstrated an increase in NUE, with northern and eastern China being the highest. The North and Northwest of China emerged as the primary source of N emission (>56 %). Sensitivity analysis indicated that NUE was mostly influenced by LF milk protein content, followed by milk production, body weight of dairy cow, and herd structure. Different forms of N emission were substantially decided by manure EFs and indoor excretion ratio. The scenario simulation suggested that the use of productive breed, low-protein feed, and N abatement procedures could enhance NUE by >30 % and reduce annual emission of NH₃ and N₂O to 38 % and 13 % of BAU. The study may provide valuable insights into the policy development of dairy industry in China, aiming at boosting productivity improvement and minimizing N loss.

Keywords: 2050 scenarios; Dairy farm; Nitrogen flow model; Nitrogen use efficiency; Sensitivity analysis.