Spatiotemporal variations of water, land, and carbon footprints of pig production in China

Pig production not only consumes large water and land, but also emits substantial greenhouse gases. Scholars have used environmental footprint, including water, land, and carbon footprints, to assess the environmental impacts of pig production. However, there is a lack of simultaneous analysis of water, land, and carbon footprints for pig production, particularly in China, the leading pig breeding and consumption country in the world. In this study, we used environmental footprint analysis to develop a water-land-carbon footprint model for pig production system from the life cycle perspective. We also examined virtual water, land and carbon flows embedded in trade. The life cycle of pig production mainly involves feed crop cultivation, feed production, and pig breeding. Then we analyzed the water, land, and carbon footprints of the pig production in China from 1990 to 2018. The findings indicated that both the total water footprint and the total land footprint increased, whereas the total carbon footprints fluctuated over the years. All the unit footprints generally decreased. Feed crop cultivation had a significant impact on the footprints. Regarding the spatial characteristics in China, all the three total footprints were generally higher in the southeast compared to the northwest. While the unit footprints in different provinces exhibited spatial heterogeneity, primarily attributed to the different feed consumptions. Overall, the trade of feed crop shifted virtual water, land and carbon flows from the north to the south, reducing the three total footprints on the whole. To achieve a resource-saving and eco-friendly pig production in China, we proposed some potential recommendations, including improving feed crop cultivation techniques, reducing feed conversion ratio, implementing precision feeding, and managing manure. We hope not only mitigate the environmental impacts of China’s pig production, but also provide references for achieving agricultural sustainability in other regions of the world.