Greenhouse gas emissions and mitigation potential of hybrid maize seed production in northwestern China

Dan Liu,Yanjun Guo,Wushuai Zhang,Xinping Chen,Xiaozhong Wang

doi:10.1007/s11356-021-16990-w

Dan Liu, Yanjun Guo + Show 3 more

Open Access

https://doi.org/10.1007/s11356-021-16990-w

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Abstract

Although hybrid maize seed production is one of the most important agriculture systems worldwide, its greenhouse gas (GHG) emissions and potential mitigation measures have not been studied. In this study, we used life cycle assessment (LCA) to quantify the GHG emissions of 150 farmers run by 6 companies in an area of northwest China known for hybrid maize seed production. The results indicated that the average reactive nitrogen (Nr) losses and GHG emissions from hybrid maize seed production were 53 kg N ha-1 and 8077 kg CO2 eq ha-1, respectively. Furthermore, the average nitrogen and carbon footprints of the process were 12.2 kg N Mg-1 and 1495 kg CO2 eq Mg-1, respectively. Nitrogen fertilizer and electricity consumption for irrigation were the main contributors to high GHG emissions, accounting for 60% and 30% of the total, respectively. The GHG emissions from seed production for different companies varied greatly with their resource input. There was also a large variation in environmental burdens among the 150 farmers. Based on an analysis of the yield group, we found that the carbon footprint of the first group (the one with the highest yield) was 27% lower than the overall average. Scenario analysis suggests that a combined reduction of N input rate, optimizing irrigation, and increasing yield can eventually mitigate the carbon footprint of hybrid maize seed production by 37%. An integrated systematic approach (e.g., ISSM: integrated soil-crop system management) can reduce the GHG emissions involved in producing hybrid maize seeds. This study provides quantitative evidence and a potential strategy for GHG emissions reduction of hybrid maize seed production.

Highlights

Agriculture is an important source of greenhouse gases (GHGs), accounting for 30% of the total anthropogenic GHG emissions (FAO, 2016)
The results indicated that the average reactive nitrogen (Nr) losses and GHG emissions from hybrid maize seed production were 53 kg N ha− 1 and 8077 kg CO2 eq ha− 1, respectively, which are higher than those of the conventional maize production system
The yields of companies GY and HX were significantly lower than the average yield, by 34% and 31%, respectively, while the other four companies had yields that were higher than the mean (Table 2)

Summary

Introduction

Agriculture is an important source of greenhouse gases (GHGs), accounting for 30% of the total anthropogenic GHG emissions (FAO, 2016). It is of great significance to quantify the emissions of different agricultural systems and define the measures to reduce GHG emissions (Gan et al, 2011). Maize is a bulk agricultural product and its planting area is increasing rapidly (Yao et al, 2021). In the past 50 years (1968–2018), the size of the maize production area worldwide has grown rapidly from 112 million hectares to 194 million hectares, an increase of 73% (FAO, 2020). Hybrid maize seed production is currently one of the most important cropping systems worldwide, with an estimated area of approximately 1.94 million hectares, based on a 1:100 area ratio of the production of seed to common maize. GHG emissions and the mitigation potential of hybrid maize seed production systems have received little attention to date, their planting area has increased rapidly

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