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  • Pinshang Xu
    Nanjing Agricultural University
  • Zhutao Li
    Nanjing Agricultural University
  • Shumin Guo
    Nanjing Agricultural University
  • Davey L Jones
    School of Environmental and Natural Sciences, Bangor University
  • Jinyang Wang
    Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs MitigationCollege of Resources and Environmental Sciences; National Academy of Agriculture Green Development; Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, China.Nanjing Agricultural University
  • Zhaoqiang Han
    Nanjing Agricultural University
  • Jianwen Zou
    Nanjing Agricultural University

Emerging evidence suggests that replacing mineral fertilizers with organic livestock manure can effectively suppress reactive gaseous nitrogen (N) emissions from soils. However, the extent of this mitigation potential and the underlying microbial mechanisms in orchards remain unclear. To address this knowledge gap, we measured nitrous and nitric oxide (N2O and NO) emissions, microbial N cycling gene abundance, and N2O isotopomer ratios in pear and citrus orchards under three different fertilization regimes: no fertilization, mineral fertilizer, and manure plus mineral fertilizer. The results showed that although manure application caused large transient peaks of N2O, it reduced cumulative emissions of N2O and NO by an average of 20 % and 17 %, respectively, compared to the mineral fertilizer treatment. Partial replacement of mineral fertilizers with manure enhanced the contribution of AOA to nitrification and reduced the contribution of AOB, thus reducing N2O emissions from nitrification. Isotope analysis suggested that the pathway for N2O production in the soils of both orchards was dominated by bacterial denitrification and nitrifier denitrification. The manure treatment reduced the ratio of denitrification products. Additionally, the dual isotope mixing model results indicated that partially replacing mineral fertilizers with manure could promote soil denitrification, resulting in more N2O being reduced. N-oxide emissions were on average 67 % higher in the pear orchard than in the citrus orchard, probably due to the differences in soil physicochemical properties and growth habits between the two orchards. These findings underscore the potential of partially replacing mineral fertilizers with organic manure in orchards to reduce gaseous N emissions, contributing to the transition towards environmentally sustainable and climate-smart agricultural practices.

Original languageEnglish
Article number171192
JournalScience of the Total Environment
Volume921
Early online date23 Feb 2024
DOIs
Publication statusPublished - 15 Apr 2024
Externally publishedYes
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