Response of area‐ and yield‐scaled <scp>N<sub>2</sub>O</scp> emissions from croplands to deep fertilization: a meta‐analysis of soil, climate, and management factors
Chen Hui, Qingxi Liao, Yitao Liao
Abstract
Abstract BACKGROUND Nitrous oxide (N 2 O) 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, N 2 O 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 (N 2 O emissions) and yield‐scaled N 2 O emissions (N 2 O intensity) from croplands to deep fertilization, and (ii) identify the soil, climate, and management factors that mitigate N 2 O emissions and N 2 O intensity under deep fertilization. RESULTS Compared with the control, deep fertilization increased N 2 O emissions by 18.6% ( P < 0.001) but decreased N 2 O intensity by 20.1% ( P = 0.018). By adopting deep fertilization, N 2 O emissions could be significantly mitigated in rice‐paddies soils (−48.8%), with fertilizer depth > 10 cm (−33.0%), and with fertilizer N amount > 200 kg N ha −1 (−8.2%). N 2 O 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 N 2 O emissions and provides potential measures to mitigate N 2 O emissions associated with deep fertilization practices.