Combined Fertilization Could Increase Crop Productivity and Reduce Greenhouse Gas Intensity through Carbon Sequestration under Rice-Wheat Rotation

Tengfei Guo,Shuiqing Zhang,Dali Song,Guoqing Liang,Haoan Luan,Wei Zhou

doi:10.3390/agronomy11122540

Abstract

Quantifying greenhouse gas intensity (GHGI) and soil carbon sequestration is a method to assess the mitigation potential of agricultural activities. However, the effects of different fertilizer amendments on soil carbon sequestration and net GHGI in a rice-wheat cropping system are poorly understood. Here, fertilizer treatments including PK (P and K fertilizers); NPK (N, P and K fertilizers), NPK + OM (NPK plus manure), NPK + SR (NPK plus straw returning), and NPK + CR (NPK plus controlled-release fertilizer) with equal N input were conducted to gain insight into the change of soil organic carbon (SOC) derived from the net ecosystem carbon budget (NECB), net global warming potential (GWP), and GHGI under rice-wheat rotation. Results showed that compared with NPK treatment, NPK + OM significantly increased wheat yield and NPK + SR caused significant increase in rice yield. Meanwhile, NPK + SR and NPK + CR treatments reduced net GWP by 30.80% and 21.83%, GHGI by 36.84% and 28.07%, respectively, which suggested that improved grain production could be achieved without sacrificing the environment. With the greatest C sequestration, lowest GHGI, the NPK plus straw returning practices (NPK + SR) might be the best strategy to mitigate net GWP and improve grain yield and NUE in the current rice-wheat rotation system.

Highlights

Atmospheric carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are potent and major long-lived greenhouse gases (GHGs) because of their strong radiative forcing
The nitrogen use efficiency (NUE) in wheat season significantly increased by 35.5%, 23.7% and 20.8% under NPK + OM, NPK + SR and NPK + CR treatments compared with NPK treatment (Figure 1)
The NUE in rice season significantly increased by 18.7%, 24.3%, and 48.8% under NPK + OM, NPK + SR and NPK + CR treatments compared with NPK treatment (Figure 1)

Summary

Introduction

Atmospheric carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are potent and major long-lived greenhouse gases (GHGs) because of their strong radiative forcing. Net GHG emission from those activities could potentially be reduced by increasing soil organic carbon (SOC) storage and/or decreasing CH4 and N2O emissions with improved farm practices, such as various fertilizer amendments in agricultural lands [4,5]. Rice–wheat rotation systems play an important role in South Asia and China, constituting ~13 million hectares in South Asia and ~4.5 million hectares along the Yangtze River valley in China [6]. This type of crop rotation, providing a stable source of food for more than 20% of the world’s population, is crucial for ensuring regional and even global food security [7]. It is important to explore the suitable N managements to guide farmers to select the appropriate fertilizers practices in improving N use efficiency, crop productivity and minimizing the negative impact on environmental quality

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