Growth, yield and NPK uptake by maize with complementary organic and inorganic fertilizers.

High and sustainable crop yields in the tropics have been reported to be only possible with judicious combination of mineral fertilizers and organic amendments. Fertilizing croppings to achieve this has usually been a difficult task to achieve. The growth and yield of maize cultivated with a complementary application of organic and inorganic fertilizers was assessed compared with sole organic and sole inorganic fertilizers between April and July 2003 and 2004 at Ibadan, Nigeria, in the degraded tropicalrain forest zone. There was a no-fertilizer treatment as the control. The organic fertilizer was an equal mixture of composted domestic waste and stale cow dung, applied at 10 tonnes ha-1. Urea and Single super phosphate were applied as the inorganic fertilizer to supply 70 kg N and 13 kg P2O5 ha-1 respectively. The mixture of organic and inorganic fertilizer treatment consisted of half the rates used for sole organic and sole inorganic fertilizer treatments: 5 tonnes organic mixture was applied, with 35 kg N and 6.5 kg P2O5. Maize plant height at 8 weeks after planting washighest with inorganic fertilizer application while the leaf area was highest with organic fertilizer application. Stover yield and cob yields were also highest with inorganic fertilizer. Complementary application of organic and inorganic fertilizers however had similar plant heights; stover yield as well as cob yields with inorganic fertilizer. Nitrogen appeared chelated with organic fertilizer application. Plant ear – leaf Nitrogen was highest (1.68%) with inorganic fertilizer while the control plots had a Nitrogen content of 1.12% which was higher than 0.84% and 0.98% N from sole organic and a complementary application of organic and inorganic fertilizers, respectively. Plant P content was increased by 136% and 15% with organic and inorganic fertilizers, respectively, but was reduced by 15% with complementaryapplication of organic and inorganic fertilizers. The K content was highest with inorganic fertilizer (1.91%). Complementary application of organic and inorganic fertilizers had a K content of 1.70% while the organic – fertilized leaves had 1.53%. Stover nutrient uptake was highest for N and K with inorganic fertilizer while the P was highest with organic fertilizer application. Cultivating maize with complementary organic and inorganic fertilizers gives a comparable cob yield as inorganic fertilizer and has nutrients higher than from sole organic fertilizer application.Key words: Maize, Fertilizer type, Nutrient uptake