posted on 2021-04-01, 23:27authored byWeitong Long, Hongliang Wang, Yong Hou, Dave Chadwick, Yifei Ma, Zhenling Cui, Fusuo Zhang
Pig production contributes considerably
to land use and greenhouse
gas (GHG) and reactive nitrogen (Nr) emissions. Land use strategies
were widely proposed, but the spillover effects on biological flow
are rarely explored. Here, we simultaneously assessed the carbon (C),
nitrogen (N), and cropland footprints of China’s pig production
at the provincial scale in 2017. The environmental impacts of land
use strategies were further evaluated. Results show that one kg live-weight
pig production generated an average of 1.9 kg CO2-equiv
and 59 g Nr emissions, occupying 3.5 m2 cropland, with
large regional variations. A large reduction in GHG (58–64%)
and Nr (12–14%) losses and occupied cropland (10–11%)
could be achieved simultaneously if combined strategies of intensive
crop production, improved feed-protein utilization efficiency, and
feeding co-products were implemented. However, adopting a single strategy
may have environmental side-effects. Reallocating cropland that pigs
used for feed to plant food alternatives would enhance human-edible
energy (3–20 times) and protein delivery (1–5 times)
and reduce C and N footprints, except for rice and vegetables. Reallocating
cropland to beef and milk production would decrease energy and protein
supply. Therefore, a proper combination of land use strategies is
essential to alleviate land use changes and nutrient emissions without
sacrificing food supply.