Maize was cultivated in post expts. on soils fertilized with mineral and org. fertilizers (manure) for 28 years and with only mineral fertilizers. The soils were addn. fertilized with NH4NO3 (2.5-7.5 g/m(2)). The yield of maize dry matter and P uptake were much higher when the org. fertilizers-contg. soils were used. The P uptake increased also with increasing the N doses during fertilizing.