NAHALi 2.1

Sustainable Lindenhof: Integration of new products and production from the farm's own organic materials into an existing farm system with arable farming, livestock breeding and biogas use

Duration
01.12.2020 - 31.08.2021

Particularly in intensive livestock farms, the purchase of concentrated feed (N, P import) results in surpluses in the form of on-farm organic residues that cannot be sensibly utilized on the limited farm area. In Germany, 60% of CH4 emissions and 80% of N2O emissions come from agriculture (UBA, 2018). This results in a need for action for farmers. The new German Fertilizer Ordinance (DüV) 2017 has more tightly regulated and capped the application of N and P to fields. Livestock farms now frequently exceed soil P levels of 20 mg/100 g soil P2O5 (CAL), the limit at which only withdrawal fertilization is allowed.Due to the P limit, farm organic fertilizer can then only be applied to the smallest extent. Therefore, intensive livestock farms are often faced with the dilemma that only about 10% of the nitrogen can actually be used for on-farm fertilization. Only 18 % of the P is used internally as fertilizer, 82 % is not utilized (Fig. 1). At the same time, despite N, P surpluses, 78 % of the N fertilizer requirement must be purchased as mineral fertilizer due to the new regulations of the German Fertilizer Ordinance (DüV). The organic fertilizer mainly accumulates as digestate in biogas plants. The digestate also contains almost all of the unused carbon in the system.Previous solutions rely, among other things, on the redistribution of N, P surpluses by transporting the farm's own organic fertilizers (liquid manure, biogas digestate, etc.) to other farms with fertilizer needs. However, these fertilizers have a high water and low nutrient content. Therefore, a transfer of the surpluses (N, P export) often fails due to the costs, because organic fertilizers are only transportable over very short distances. Nevertheless, the pressure on intensive livestock farms is increasing due to the fierce price competition and cost pressure, forcing them to engage in so-called "manure tourism". Society no longer tolerates the externalization of environmental problems and has banned the overfertilization of farmland by various means, especially the new German Fertilizer Ordinance (DüV), in order to protect groundwater from nitrate and germs and ecosystems from eutrophication by N and P. This leaves farms without a solution to their environmental problems. As a result, farms are left without a solution to their disposal problem and solve it by exporting manure. This may make the environmental impact more acceptable, but not less.