Maize Growth, Yield and Soil Nutrient Changes With N-Enriched Organic Fertilizers

Experiments were conducted in the growing seasons of 2005 and 2006 at Ibadan, Nigeria, in the degraded tropical rain forest zone to assess the growth and yield of maize with Nitrogen-enriched organic fertilizer made from municipal waste and cow dung (2.5t ha^-1 Pacesetter fertilizer + 100kg ha^-1 urea)and also with Nitrogen-fortified poultry manure. Their performance was compared with those of inorganic NPK fertilizer and no fertilizer control. Maize growth was significantly (P=0.05) affected by an enrichment of the organic manures. They had plants comparable in height with inorganic fertilizer application. At harvest, plants treated with fortified poultry manure were about 259cm tall while those treated with fortified Pacesetter fertilizer and the plants treated with inorganic fertilizer were about 253cm tall. Average plant leaf areas were similar with the fortified fertilizers and with inorganic fertilization. Length of days taken to achieve 50% tasselling was also reduced with fertilization. Inorganic fertilizer application gave plants that achieved 50% tasselling in 50days while fortified poultry manured - plants took 52days and the fortified Pacesetter fertilizer – treated plants took 53days. Fertilization of maize gave significantly (P=0.05) higher seed yields. Fortified poultry manure gave an average yield of 3.97t ha^-1 while fortified Pacesetter fertilizer had an average of 3.78t ha^-1.Inorganic fertilizer gave a yield of 3.70t ha^-1 while a significantly lower yield of 2.48t ha^-1 was given by the unfertilized plants. Maize growth and yield from the enriched organic manures were comparable with inorganic fertilizer, indicating the potentials of the use of fortified organic manures as alternatives to inorganic fertilizers. Poultry manure required lesser N-fortification to give comparable seed yields as cow dung. Although both organic manures increased the soil N and P, poultry manure gave higher values while the soil K, Ca and Mg contents were more increased with the cow dung than poultry manure. Poultry manure, fortified with 100kg Urea can be applied at 2.5t ha^-1 to cultivate maize. It gives a comparable yield as inorganic fertilizer and increases the soil N and P.