EFFECTS OF NITROGEN AND MICRONUTRIENTS ON YIELD AND PROTEIN QUALITY OF MAIZE IN A NORTHERN GUINEA SAVANNA ALFISOL OF NIGERIA

EFFECTS OF NITROGEN AND MICRONUTRIENTS ON YIELD AND PROTEIN QUALITY OF MAIZE IN A NORTHERN GUINEA SAVANNA ALFISOL OF NIGERIA

Abstract:

The experiment consisted of a greenhouse and field experiments. The field experiments were conducted during the rainy seasons of 2008 and 2009 at the Institute for Agricultural Research farm in Samaru (110 11‟ N, 70 38‟E) within the northern Guinea savanna ecological zone of Nigeria to study the effects of nitrogen and micronutrients on yield and protein quality of maize. The study was therefore conducted with the following objectives; to determine the suitable levels of nitrogen and micronutrients on the yield of quality protein maize and normal maize varieties in the northern Guinea savanna, to establish the effects of nitrogen and micronutrients on the lysine and tryptophan contents of maize as well as to determine the soil nutrient factors influencing the nutritional quality of QPM varieties introduced to the northern Guinea savanna in comparison with normal maize. The greenhouse and field treatments consisted of four rates of nitrogen fertilizer (0, 50, 100 and 150kgNha-1), two rates of micronutrients (0, cocktail mixtures) Cu, Fe, Zn, B and Mo and four maize varieties SAMMAZ 14 and SUSUMA (QPM) and SAMMAZ 11 and SAMMAZ 12 (normal maize) which gave a total of thirty-two (32) treatments with basal application of 60kgha-1P as P2O5 and 60kgha-1K as K2O. These were tested in a completely randomized design in the greenhouse and randomized complete block design on the field with three replications with a total of 96pots/plots respectively. The fertilizer treatments were factorially combined. The results from the study revealed that in the greenhouse micronutrients application enhanced the performance of the QPM than the normal maize. SUSUMA variety (QPM) was superior in performance than SAMMAZ 14 (QPM) in that it produced taller plants (65.50cm), more number of leaves (12.75) and higher dry matter yield of 6.67g/pot at low application of nitrogen (50kgNha-1). The results from the field showed that all the maize varieties responded well to the nitrogen applied and that the QPM (SAMMAZ 14 and SUSUMA) varieties were superior in their response to nitrogen in that they responded significantly to nitrogen rate of 100kgNha-1 while the normal maize (SAMMAZ 11 and SAMMAZ 12) responded to nitrogen at the highest rate applied (150kgha-1) in this order of response SUSUMA> SAMMAZ 14 > SAMMAZ 11 > SAMMAZ 12.The Stover yield, plant height, 1000-grain weight, cob length and cob diameter were increased as nitrogen fertilizer increased from 0- 150kgNha-1. The interaction between nitrogen fertilizer and micronutrients gave a crude protein content of 9.1%, lysine content of 14.3% and tryptophan content of 16.7% by the QPM varieties over the normal maize varieties. SUSUMA the most superior variety gave lysine and tryptophan contents of 3.19% and 5.08% higher than SAMMAZ 11(NORMAL MAIZE). The correlation analysis showed that all the agronomic parameters, total nitrogen, calcium, zinc, copper, boron and soil pH influenced and increased the grain yield positively. The principal component and correlation coefficient analysis revealed that as grain yield increased the nitrogen and protein contents of the maize decreased. The factors most responsible for enhanced grain quality in the QPM varieties from the correlation analysis and PCA were nitrogen, potassium, calcium and zinc contents of the soil. Gross margin analysis showed that SUSUMA (QPM) variety was more profitable than SAMMAZ 14, SAMMAZ 12 and SAMMAZ 11. It produced higher grain yield at 50kg N/ha and with the application of micronutrients. Farmers can therefore adopt the QPM varieties (SUSUMA and SAMMAZ 14) since it is easy to cultivate like the normal maize in the same environment and climatic conditions with higher yield and of more quality than the normal maize.

EFFECTS OF NITROGEN AND MICRONUTRIENTS ON YIELD AND PROTEIN QUALITY OF MAIZE IN A NORTHERN GUINEA SAVANNA ALFISOL OF NIGERIA