Zhanlei Pan, Zhenggui Zhang, Junhong Li, Yaopeng Zhang, Menghua Zhai, Wenqi Zhao, Lizhi Wang, Ao Li, Kunfeng Wang, Zhanbiao Wang

Sustainable Production and Consumption

Doi: 10.1016/j.spc.2024.09.022

Abstract：

Globally, acquiring information on region- and crop-specific nitrous oxide (N2O) emissions is vital for establishing effective N2O mitigation strategies. Soil cultivated with cotton (Gossypium hirsutum L.) is an important source of N2O in agricultural production. However, little is known about the magnitudes and main drivers of soil N2O emissions from cotton fields worldwide. In this meta-analysis, we were the first to synthesize 34 peer-reviewed papers (298 observational datasets) to quantify the magnitudes and controlling factors of area-scaled N2O emissions (N2O area), direct N2O emission factors (EFd), and yield-scaled N2O emissions (N2O yield) from the soils of cotton fields and to explore associated potential mitigation strategies. On average, the N2O area from global cotton-planted soils was 2.10 kg N ha-1, with a mean EFd of 0.92 %, which is comparable to those reported for cereal crops (e.g., maize, 1.02 %) and the Intergovernmental Panel on Climate Change default value of 1 % for global croplands. The global mean N2O yield estimated here was 622 g N Mg-1. At the global scale, the variations in all N2O -related indices in the soils of cotton fields were demonstrated to be primarily controlled by climatic conditions (e.g. climate type) and soil properties (e.g., bulk density, pH, C/N or soil texture) rather than by well-recognized management practices (e.g., N fertilization rate). Furthermore, our analysis showed that the application of urease and/or nitrification inhibitors significantly reduced soil N2O emissions while maintaining seed cotton yields. These findings emphasize that cotton production has an obvious climate footprint and provide potential N2O mitigation options for the sustainable intensification of cotton production.