Agriculture is expected to feed an increasing global population while at the same time meeting demands for renewable energy and the supply of ecosystem services such as provision of nutrient cycling and carbon sequestration. However, the current structure of the agricultural system works against meeting these expectations. The spatial separation of crop and livestock farms has created negative environmental consequences, and bioenergy production has created a trade-off between food and energy production. In this paper, we explore the opportunities for ecological intensification at a regional scale made possible by combining food and energy production. We built three scenarios representing farming systems including biogas production using grass biomass and manure. These scenarios included the following: (a) The current system with energy production (CSE) from non-edible agricultural biomasses (CSE). (b) Agroecological symbiosis (AES) identical to CSE except with 20% of the arable cropping area converted to clover-grasses for use in biogas production. (c) Agroecological symbiosis with livestock (AES-LST) where the available grass biomass (20% as in the AES) is fed to livestock and manure then used as a feedstock in biogas production. In each scenario, nutrients were circulated back to crops in the form of digestate. The supply of soil functions (primary production for food and energy, provision of nutrient cycling, and climate mitigation) and impacts on water quality through nutrient losses in these three scenarios were then compared to the current system. Integrating biogas production into food production resulted in an increased supply of nutrient recycling, reduced nutrient losses, and increased carbon inputs to the soils indicating enhanced climate mitigation. Food production was either not affected (CSE), increased (AES-LST), or decreased (AES), and biogas was produced in substantial quantities in each scenario. Our study demonstrated potential synergies in integrating food and energy production without compromising other ecosystem services in each scenario.
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