Influence of organo-mineral fertilization on wheat and maize crops and the evolution of soil fertility under long-term experiments in the Moldavian Plain

Abstract

The investigations conducted during 1996-2007 at the Podu-Iloaiei Agricultural Research Station have studied the influence of different organo-mineral fertilization rates on wheat and maize yield and soil agrochemical characteristics. In wheatmaize crop rotation, applying mineral fertilizers has resulted in getting mean yield increases. The organic fertilizers, applied together with mineral ones (N50P50+60 t manure/ha), have improved soil chemical characteristics and determined mean yield increases of 125% in wheat and 108% in maize. The mean yield increases, obtained for each kg of a.i. of applied fertilizer, were comprised between 7.6 and 17.5 kg in wheat and between 13.0 and 28.1 kg in maize. In the intensive rotations with cereals, with high annual consumption of nutrients, maintaining a good soil supply with humus and mineral elements was done only by the organo-mineral fertilization (N50P50 or N100P100 + 40 t manure/ha). In the soils from the Moldavian Plateau, which are poor in organic matter and nutrients, the proper use of different organic resources may replace a part of high technological consumption, determined the improvement in the content of organic matter from soil and ensured better conditions for the capitalization of nitrogen fertilizers. On the Cambic Chernozem from the Moldavian Plateau, a good supply with mobile phosphorus in wheat and maize crops (37-72 mg/kg) was done in case of the annual application of a rate of N100P100, while a very good supply (72-91 mg/kg) was achieved at the rate of N50P50+60 t/ha manure.