Ecological intensification by integrating biogas production into nutrient cycling: Modeling the case of Agroecological Symbiosis

Abstract

There is growing demand to produce both food and renewable energy in a sustainable manner, while avoidingcompetition between food and energy production. In our study, we investigated the potential of harnessingbiogas production into nutrient recycling in an integrated system of organic food production and food proces-sing. We used the case of Agroecological Symbiosis (AES) at Palopuro, which is a combination of three farms, abiogas plant, and a bakery, as a case to explore how biogas production using feedstocks from the farms can beused to improve nutrient cycling, and to calculate how much energy could be produced from the within-systemfeedstocks. The current system (CS) used in organic farms, and the integrated farm and food processing AESsystem, were analyzed using Substance Flow analysis. In the AES, annual nitrogen (N) and phosphorus (P)surpluses were projected to be reduced from 95 kg ha−1to 36 kg ha−1and from 3.4 kg ha−1to −0.5 kg ha−1 respectively, compared to the CS. Biogas produced from green manure leys as the major feedstock, produced2809 MWh a−1. This was 70% more than the energy consumed (1650 MWh a−1) in the systemand thus the AESsystem turned out to be a net energy producer. Results demonstrated the potential of biogas production toenhance the transition to bioenergy, nutrient recycling, and crop productivity in renewable localized farmingand food systems