Biogas digestate and its economic impact on farms and biogas plants according to the upper limit for nitrogen spreading—the case of nutrient-burdened areas in north-west Germany

At the end of 2012, an expert group presented its evaluation of the forthcoming amendment of the German Fertilizer Ordinance (DüV). The new proposal intends to include manure of plant origin in the calculation of the upper limit for nitrogen spreading, determined to be 170 kg per hectare. This would particularly affect regions of north-west Germany that are characterized by intensive animal husbandry and biogas production. This would lead to increased costs of the disposal of manure and the use of agricultural land, especially for pig farms and biogas producers. A spatial model of nutrient distribution demonstrates the regional impacts of the amendment, and example calculations at an enterprise level show that many farmers would no longer be able to suitably pay for the factors used. Monte Carlo analysis shows a relatively high probability that only successful pig farmers and biogas producers would be able to compensate for the rising costs of transport and land use in a sustainable manner. Successful piglet producers would improve their relative competitiveness compared to biogas producers and especially to pig-fattening enterprises. The adoption of new strategies should factor in both the water protection requirements and the ability of the affected farms to evolve and grow on a sustainable basis.