Ecological intensification by integrating biogas production into nutrient cycling : Modeling the case of Agroecological Symbiosis
Koppelmäki, Kari ; Parviainen, Tuure ; Virkkunen, Elina ; Winquist, Erika ; Schulte, Rogier P.O. ; Helenius, Juha - \ 2019
Agricultural Systems 170 (2019). - ISSN 0308-521X - p. 39 - 48.
Biological nitrogen fixation - Localized agrifood system - Nutrient losses - Organic farming - Renewable energy - Sustainable intensification
There is growing demand to produce both food and renewable energy in a sustainable manner, while avoiding competition between food and energy production. In our study, we investigated the potential of harnessing biogas production into nutrient recycling in an integrated system of organic food production and food processing. We used the case of Agroecological Symbiosis (AES) at Palopuro, which is a combination of three farms, a biogas plant, and a bakery, as a case to explore how biogas production using feedstocks from the farms can be used to improve nutrient cycling, and to calculate how much energy could be produced from the within-system feedstocks. The current system (CS) used in organic farms, and the integrated farm and food processing AES system, 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−1 to 36 kg ha−1 and from 3.4 kg ha−1 to −0.5 kg ha−1 respectively, compared to the CS. Biogas produced from green manure leys as the major feedstock, produced 2809 MWh a−1. This was 70% more than the energy consumed (1650 MWh a−1) in the systemand thus the AES system turned out to be a net energy producer. Results demonstrated the potential of biogas production to enhance the transition to bioenergy, nutrient recycling, and crop productivity in renewable localized farming and food systems.
|An assessment of current and critical nitrogen and phosphorus losses from European agricultural soils
Kros, J. ; Vries, W. de; Römkens, P.F.A.M. ; Voogd, J.C. - \ 2015
In: Proceedings - 21st International Congress on Modelling and Simulation, MODSIM 2015. - Modelling and Simulation Society of Australia and New Zealand Inc. (MSSANZ) (Proceedings - 21st International Congress on Modelling and Simulation, MODSIM 2015 ) - ISBN 9780987214355 - p. 1275 - 1281.
Agriculture - Leaching - N and P balances - NH emission - Nutrient losses
Since the early 1940s, European agriculture has intensified greatly, resulting in large inputs of nitrogen (N) and phosphorus (P) to soil by fertilizers and manure. This has led to an increase in crop growth and soil fertility in terms of elevated N and P contents. However, the increased application of fertilizers and manure also induced adverse effects, such as: (i) loss of biodiversity in natural ecosystems due to increased emission and deposition of ammonia, (ii) increased levels of nitrogen in drinking water reservoirs due to leaching of nitrate to ground water and (iii) eutrophication of surface waters due to increased runoff of N and P. Main aim of this study therefore was to identify regions where N and P loads used for agricultural production lead to the adverse impacts listed above. This was assessed by comparing current N and P losses from agriculture with critical losses, calculated at a high spatial resolution for the entire European Union using the INTEGRATOR model. Current N and P losses were based on calculations using current detailed agronomic and biophysical data. Critical N and P losses were based on critical NH3 emissions, NO3 leaching rates, as well as N and P runoff rates. Critical NH3 emissions were related to national emission ceilings in view of biodiversity loss. Critical leaching and runoff levels were derived from critical N and P concentrations in view of drinking water quality and eutrophication, respectively. Calculated current (2010) N and P balances show that they are highly spatially variable and largely related to the livestock distribution. The critical P runoff to surface waters is most often exceeded followed by N runoff to surface waters and NO3 leaching to groundwater.