o:730 Microgranular fertilizer and biostimulants as alternatives to diammonium phosphate fertilizer in maize production on marshland soils in northwest Germany en Abstract: The eutrophication of groundwater through widespread diammonium phosphate (DAP) fertilization and excessive farm fertilizer is one of the major problems in European agriculture. Organomineral microgranular fertilizers that have a reduced phosphorus (P) content, alone or in combination with biostimulants, offer promising alternatives to DAP fertilization. We conducted a field experiment with maize (Zea mays) on a marshland soil site in order to compare the yield increase and the phosphorus balance of DAP and microgranular fertilizer variants. P content of the soil on the study site is 3.9 g P per 100 g soil. Treatments involved a combination of two fertilizers, namely DAP or a P-reduced microgranular slow-release organomineral fertilizer (Startec) and the biostimulants mycorrhiza, humic substances and soil bacteria, applied individually or along with two of the above biostimulants. Fertilizer variants were also tested individually without additional biostimulants. One in four plots was used as a control, treated only with biogas slurry, to identify site-specific spatial variability and to implement correction factors to process raw data using standardized methods. Startec performed as well as DAP in terms of both the yield and corn cob ratio, while the P excess was lower in plots treated with Startec (av. = 4.5 kg P2O5 ha-1) compared to DAP (av. = 43.7 kg P2O5 ha-1). The latter differences are of statistical significance. Individual biostimulants and a combination of multiple biostimulants rarely resulted in significantly higher yields, with the exception of some combinations with humic substances and mycorrhiza in individual years. The influence of the climatic conditions in each of the years was higher than the influence of the biostimulants. However, average increases in yield over three years would be economically beneficial for farmers in the case of the applied humic substances product and mycorrhiza. An adequate alternative to DAP was found in the form of a Preduced microgranular fertilizer from Startec. microgranular fertilizer, diammonium phosphate, eutrophication, phosphorus balance, biostimulants 1552099 10.5937/ZemBilj2201053T 2022-10-07T07:33:45.804Z 44 yes 46 Matthias Thielicke Leibniz Center for Agricultural Landscape Research 46 Julian Ahlborn Senckenberg Museum of Natural History 46 Ljubomir Životić Poljoprivredni fakultet Univerziteta u Beogradu 46 Elmira Saljnikov Institut za zemljište 0000-0002-6497-2066 46 Frank Eulenstein Leibniz Center for Agricultural Landscape Research application/pdf 860796 https://unilib.phaidrabg.rs/o:730 no yes 21 70 92000001 71A05 Zemljište i biljka 71 1 53 66 2022