Greenhouse gas emissions from cotton field under different irrigation methods and fertilization regimes in arid northwestern China.

Jie Wu,Xiaohua Wang,Jinfei Feng,Xinmin Bian,Wei Guo,Haishui Yang,Lanhai Li

doi:10.1155/2014/407832

Abstract

Drip irrigation is broadly extended in order to save water in the arid cotton production region of China. Biochar is thought to be a useful soil amendment to reduce greenhouse gas (GHG) emissions. Here, a field study was conducted to compare the emissions of nitrous oxide (N2O) and methane (CH4) under different irrigation methods (drip irrigation (D) and furrow irrigation (F)) and fertilization regimes (conventional fertilization (C) and conventional fertilization + biochar (B)) during the cotton growth season. The accumulated N2O emissions were significantly lower with FB, DC, and DB than with FC by 28.8%, 36.1%, and 37.6%, while accumulated CH4 uptake was 264.5%, 226.7%, and 154.2% higher with DC, DB, and FC than that with FB, respectively. Irrigation methods showed a significant effect on total global warming potential (GWP) and yield-scaled GWP (P < 0.01). DC and DB showed higher cotton yield, water use efficiency (WUE), and lower yield-scaled GWP, as compared with FC and FB. This suggests that in northwestern China mulched-drip irrigation should be a better approach to increase cotton yield with depressed GHG. In addition, biochar addition increased CH4 emissions while it decreased N2O emissions.

Highlights

Crop cultivation stimulates greenhouse gas (GHG) emissions from soil to the atmosphere from agricultural practices such as irrigation and fertilization, which in turn influences the biogeochemical process of carbon and nitrogen (N) in the soil
The emissions of GHG from crop land have been estimated to account for 13.5% of the anthropogenic emissions worldwide [1]
How to reduce GHG emissions from agricultural practices without yield loss is an urgent task for crop production

Summary

Introduction

Crop cultivation stimulates greenhouse gas (GHG) emissions from soil to the atmosphere from agricultural practices such as irrigation and fertilization, which in turn influences the biogeochemical process of carbon and nitrogen (N) in the soil. How to reduce GHG emissions from agricultural practices without yield loss is an urgent task for crop production. Improving the cropping practices is a recommended strategy to mitigate greenhouse gas emissions from agricultural soil [1]. This strategy is highly dependent on the crops, since the cropping practices varied with crop species [2]. Considerable field experiments have documented large amount of N2O emitted from cotton field due to high N fertilizer input and immoderate irrigation [4,5,6]

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