A meta-analysis of management practices for simultaneously mitigating N2O and NO emissions from agricultural soils

Abstract

Evidence from individual field measurements indicates that nitrous oxide (N2O) and nitric oxide (NO) emissions respond to a certain management practice in a similar or divergent manner. The objective of this study is to quantify the effects of various management practices on N2O and NO emissions and crop yields by performing a pairwise meta-analysis. We collected 39 peer-reviewed publications that recorded simultaneous measurements of N2O and NO emissions from various agroecosystems. Five management practices, namely reducing nitrogen (N) fertilizer input, application of enhanced efficiency fertilizers, biochar or aged organic materials (such as compost, animal wastes and oil cake), and drip irrigation, decreased both N2O (ranging from −24.9 % to −2.6 %) and NO (ranging from −48.1 % to −8.0 %) emissions. Reducing more than 25 % of the full N input is not recommended because of the significant loss of crop yields. Two management practices, namely returning crop residues and no-tillage, increased N2O emissions (ranging from 6.1 % to 12.9 %) and decreased NO emissions (ranging from −32.1 % to −21.2 %). The divergent effects highlight the importance of reasonably managing crop residues and no-tillage to limit N2O emissions.