Two granulated P biofertilizers made from sewage sludge ash and sewage sludge ash with animal bones (both prepns. enriched with Acidithiobacillus ferrooxidans) were compared in field expts. on winter wheat to a com. superphosphate fertilizer at 3 P2O5 levels (40-80 kg/ha). Wheat yield, ear d., no. of grains in the ear, the mass of 1000 grains, biomass dynamics, lodging, weed infestation, and intensity of fungal diseases were studied. Biofertilizers equalled superphosphate in terms of its crop-enhancing efficiency. They showed the best efficiency when used at a P2O5 dose of 60 kg/ha. The increasing the dose up to 80 kg was no longer justified. The tested fertilizers did influence neither wheat lodging nor weed growth nor of fungal pathogens infestation.