Response of area‐ and yield‐scaled N2O emissions from croplands to deep fertilization: a meta‐analysis of soil, climate, and management factors

BACKGROUND Nitrous oxide (N2O) is an important and persistent greenhouse gas making a significant contribution to global climate change. Deep fertilization has been demonstrated to increase crop yield and nutrient use efficiency by decreasing losses of volatilization and surface runoff. However, N2O emissions from croplands induced by deep fertilization are variable and mitigation strategies remain uncertain. This study aimed to (i) quantify the response of area‐scaled (N2O emissions) and yield‐scaled N2O emissions (N2O intensity) from croplands to deep fertilization, and (ii) identify the soil, climate, and management factors that mitigate N2O emissions and N2O intensity under deep fertilization. RESULTS Compared with the control, deep fertilization increased N2O emissions by 18.6% (P 10 cm (−33.0%), and with fertilizer N amount > 200 kg N ha−1 (−8.2%). N2O intensity following deep fertilization significantly decreased in soils with pH ≤6 (−22.5%), at sites with precipitation of 500–1000 mm (−25.5%), in rice‐paddies soils (−53.0%), with the method of mixed fertilizer in the control (−21.2%), and with fertilizer depth > 10 cm (−33.6%). CONCLUSION This study provides a basis for assessing the effect of deep fertilization on N2O emissions and provides potential measures to mitigate N2O emissions associated with deep fertilization practices.