Carbon footprint of grain production in China

Dan Zhang,Jianbo Shen,Yu’E Li,Fusuo Zhang,Weifeng Zhang

doi:10.1038/s41598-017-04182-x

Abstract

Due to the increasing environmental impact of food production, carbon footprint as an indicator can guide farmland management. This study established a method and estimated the carbon footprint of grain production in China based on life cycle analysis (LCA). The results showed that grain production has a high carbon footprint in 2013, i.e., 4052 kg ce/ha or 0.48 kg ce/kg for maize, 5455 kg ce/ha or 0.75 kg ce/kg for wheat and 11881 kg ce/ha or 1.60 kg ce/kg for rice. These footprints are higher than that of other countries, such as the United States, Canada and India. The most important factors governing carbon emissions were the application of nitrogen fertiliser (8–49%), straw burning (0–70%), energy consumption by machinery (6–40%), energy consumption for irrigation (0–44%) and CH4 emissions from rice paddies (15–73%). The most important carbon sequestration factors included returning of crop straw (41–90%), chemical nitrogen fertiliser application (10–59%) and no-till farming practices (0–10%). Different factors dominated in different crop systems in different regions. To identity site-specific key factors and take countermeasures could significantly lower carbon footprint, e.g., ban straw burning in northeast and south China, stopping continuous flooding irrigation in wheat and rice production system.

Highlights

Due to the increasing environmental impact of food production, carbon footprint as an indicator can guide farmland management
Life cycle analysis (LCA) has been developed as a tool to estimate carbon emissions internationally[13], but this methodology has not been applied to grain production in whole China
In calculating the carbon footprint, we found that the three crops emitted more carbon than they sequestered

Summary

Introduction

Due to the increasing environmental impact of food production, carbon footprint as an indicator can guide farmland management. Grain production technologies, including the use of fertilisers and pesticides, have significantly changed in China, and the increase in agricultural inputs has been important to the development of sustainable agriculture as well as human society[10] Do these inputs result in greenhouse gas emissions after their application in the field, but large quantities of greenhouse gases are generated during their upstream production. Straw burning has become an increasingly serious phenomenon as rural households have eliminated straw as a daily energy source, the practice produces significant greenhouse gas emissions but leads to air pollution and haze, both of which are harmful to human health These changes have not been adequately considered in previous research[8, 11], so there are uncertainties regarding their impacts that interfere with the development of low-carbon agriculture[12]. Nitrogen fertiliser input kg N2O/ha 253 ± 113 ab 232 ± 117 ab 208 ± 79 a 214 ± 101 a 328 ± 139 c 287 ± 118 bc 246 ± 87 ab 231 ± 70 ab 180 ± 48 a 209 ± 71 ab 254 ± 102 b 210 ± 83 ab 178 ± 44 b 185 ± 79 b 188 ± 84 b 154 ± 51 b 154 ± 50 b 156 ± 54 b 251 ± 108 c 304 ± 102 d 114 ± 35 a Electricity Proportion of Diesel consumption households consumption for irrigation applying manure kg/ha kW h/ha

Results

Discussion

Conclusion