Economic, energy and environmental consequences of shifting from maize-wheat to forage rotation in the North China Plain

Intensive self-sufficient forage production is one of the dominant challenges for the boosting intensification of livestock production. However, there is limited information on the economic, energy and environmental consequences of converting conventional crop systems with intensive forage production systems. Based on 4-year field experiments, this work proposed a comprehensive assessment of the shift from maize-wheat (M-W) to forage production systems [silage maize-ryegrass (SM-R), sweet sorghum-ryegrass (SS-R), and sorghum-sudangrass hybrids-ryegrass (SH-R)] from economic, energy, and environmental perspectives in the northern part of the North China Plain (NCP). The results revealed that SH-R had the highest yields of dry shoot biomass and crude protein, followed by SS-R, SM-R, and M-W. Similar trends were also found for the net return, ratio of income to costs, net energy output, energy use efficiency, and energy productivity. Furthermore, the environmental assessment through a life cycle assessment suggested that compared with the M-W, the total potential environmental impacts for the product-based indicators were reduced by 50%, 55%, and 72% in SM-R, SS-R, and SH-R, respectively, even if crop protection was based on a prophylactic approach. Thus, shifting from maize-wheat to forage rotation systems, especially the sorghum-sudangrass hybrids-ryegrass system, may be promising for forage production in the northern part of the NCP. This work provides valuable insight into forage production system design and environmental change adaptation for improving food security and achieving green/circular economy.