Characterizing Greenhouse Gas Emissions and Global Warming Potential of Wheat-Maize Cropping Systems in Response to Organic Amendments in Eutric Regosols, China

Hamidou Bah,Yanqiang Wang,Xiao Ren,Jialiang Tang,Bo Zhu

doi:10.3390/atmos11060614

Abstract

Characterizing greenhouse gas (GHG) emissions and global warming potential (GWP) has become a key step in the estimation of atmospheric GHG concentrations and their potential mitigation by cropland management. However, the impacts of organic amendments on GHG, GWP, and yield-scaled GWP on cropland have not been well documented. Here, we investigate four amendment treatments (no amendment, mineral fertilizers, and pig slurry or crop residue combined with mineral fertilizers) during a two-year field experiment in rain-fed wheat-maize cropping systems. The results show that the average annual cumulative methane (CH4) flux ranged from −2.60 to −2.97 kg·C·ha−1 while nitrous oxide (N2O) flux ranged from 0.44 to 4.58 kg·N·ha−1 across all four treatments. N2O emissions were significantly correlated with soil inorganic nitrogen (i.e., NH4+-N and NO3−-N), and soil dissolved organic carbon (DOC) during both the winter wheat and summer maize seasons. On average, organic amendments combined with mineral fertilizers increased the annual GWP by 26–74% and yield-scaled GWP by 19–71% compared to those under only mineral fertilizers application. This study indicates that the fertilization strategy for Eutric Regosols can shift from only mineral fertilizers to organic amendments combined with mineral fertilizers, which can help mitigate GHG emissions and GWP while maintaining crop yields.

Highlights

Wheat and maize are among the main sources of carbohydrates for human consumption; the production of these grains is expected to increase by 1.3% per year by 2025 [1,2].Along with the growing increase in carbohydrate demand, the production of cereal grains, such as wheat and maize, must be continued, while more land will require agricultural and fertilizer applications to sustain productivity
This study indicates that the fertilization strategy for Eutric Regosols can shift from only mineral fertilizers to organic amendments combined with mineral fertilizers, which can help mitigate greenhouse gas (GHG) emissions and global warming potential (GWP) while maintaining crop yields
The four treatments evaluated in this study had various effects on seasonal and annual CH4 and nitrous oxide (N2 O) emissions, GWP, and yield-scaled GWP

Summary

Introduction

Wheat and maize are among the main sources of carbohydrates for human consumption; the production of these grains is expected to increase by 1.3% per year by 2025 [1,2]. Along with the growing increase in carbohydrate demand, the production of cereal grains, such as wheat and maize, must be continued, while more land will require agricultural and fertilizer applications to sustain productivity. For over two decades reports have shown that the world’s food production occurs in 37% of its total land area, and, as a consequence, agricultural practices have become a key source of methane (CH4 ). Atmosphere 2020, 11, 614; doi:10.3390/atmos11060614 www.mdpi.com/journal/atmosphere (i.e., manure and crop residue) to soil for crop production purposes is responsible for the increased CH4 and N2 O emissions from agricultural practices [7,8,9]. According to Ravishankara and colleagues [7], CH4 and N2 O emissions from agriculture contribute approximately 20% to global radiative forcing

Objectives

Methods

Results

Discussion

Conclusion