New technologies reduce greenhouse gas emissions from nitrogenous fertilizer in China

Abstract

Synthetic nitrogen (N) fertilizer has played a key role in enhancing food production and keeping half of the world's population adequately fed. However, decades of N fertilizer overuse in many parts of the world have contributed to soil, water, and air pollution; reducing excessive N losses and emissions is a central environmental challenge in the 21st century. China's participation is essential to global efforts in reducing N-related greenhouse gas (GHG) emissions because China is the largest producer and consumer of fertilizer N. To evaluate the impact of China's use of N fertilizer, we quantify the carbon footprint of China's N fertilizer production and consumption chain using life cycle analysis. For every ton of N fertilizer manufactured and used, 13.5 tons of CO 2 -equivalent (eq) (t CO 2 -eq) is emitted, compared with 9.7 t CO 2 -eq in Europe. Emissions in China tripled from 1980 [131 terrogram (Tg) of CO 2 -eq (Tg CO 2 -eq)] to 2010 (452 Tg CO 2 -eq). N fertilizer-related emissions constitute about 7% of GHG emissions from the entire Chinese economy and exceed soil carbon gain resulting from N fertilizer use by several-fold. We identified potential emission reductions by comparing prevailing technologies and management practices in China with more advanced options worldwide. Mitigation opportunities include improving methane recovery during coal mining, enhancing energy efficiency in fertilizer manufacture, and minimizing N overuse in field-level crop production. We find that use of advanced technologies could cut N fertilizer-related emissions by 20-63%, amounting to 102-357 Tg CO 2 -eq annually. Such reduction would decrease China's total GHG emissions by 2-6%, which is significant on a global scale.carbon accounting | life cycle assessment | food security | policy

Net global warming potential and greenhouse gas intensity in a double-cropping cereal rotation as affected by nitrogen and straw management

“…The higher emission factor was due 70 and 86 % to Chinese primary energy consumption and the energy consumed in N fertilizer production being dependent on coal (Crompton and Wu, 2005;Zhang et al, 2013), which has a greater GWP (methane and carbon dioxide emission from mining and combustion of coal) and lower energy efficiency than other sources of energy such as natural gas and nuclear power . In the present study the GHGI from the N fertilizer and electricity production accounted for 37-50 and 19-34 % of the total positive GHGI, respectively.…”

“…The GHGI values of the N application treatments were 252-393 kg CO 2 -eq Mg −1 grain in this study, higher than the values from irrigated maize in central Nebraska, where the GHGI was 230 kg CO 2 -eq Mg −1 grain (Grassini and Cassman, 2012) because of low emission factors for N fertilizer production (2.6 kg CO 2 -eq kg −1 in the US vs. 8.3 kg CO 2 -eq kg −1 in China) and electricity generation (0.6 kg CO 2 -eq (kW h) −1 in the US vs. 1.3 kg CO 2 -eq (kW h) −1 in China) (Grassini and Cassman, 2012;Zhang et al, 2013). The higher emission factor was due 70 and 86 % to Chinese primary energy consumption and the energy consumed in N fertilizer production being dependent on coal (Crompton and Wu, 2005;Zhang et al, 2013), which has a greater GWP (methane and carbon dioxide emission from mining and combustion of coal) and lower energy efficiency than other sources of energy such as natural gas and nuclear power .…”

On-farm trials of optimal fertilizer recommendations for the maintenance of high seed yields in winter oilseed rape (Brassica napus L.) production

“…In recent decades, the global fertilizer industry has experienced significant growth, and, in 2011, 176.9 Mt of fertilizer was used worldwide (Heffer and Prud'homme 2012). However, the rapid growth of the fertilizer industry and an imperfect fertilizer recommendation system have resulted in the inconsistent and inappropriate application of fertilizer in agricultural production, with consequent environmental risks (Ju et al 2006;Zhang et al 2013). Excessive fertilizer inputs are common occurrences in modern agriculture, especially in China, whereas the applications of fertilizer are insufficient in other regions of the world, such as Africa and low-income countries of Asia (Larson and Frisvold 1996;Hossain and Singh 2000;Vitousek et al 2009), and for certain crops (such as oil crops) in China (Xu 2012).…”

Manure management for greenhouse gas mitigation

“…It can be as high as 1 to 2 t N/ha per year. If greater account was made of manure nutrients, especially N, for crop supply, then less fertiliser N would need to be applied, reducing the carbon footprint of production and use of fertilisers (Zhang et al, 2013). A reduction in these excessive applications would reduce direct and indirect (via NO 3 2 leaching) emissions of N 2 O from soil, especially if one considers the non-linear relationship between application rate and direct emissions (e.g., Cardenas et al, 2010).…”