Effect of NPK Fertilizer and Cropping Ratios on Nutrient Uptake and Quality Components of Maize (Zea mays) and Egusi Melon (Colocynthis citrullus)

Field trials were conducted in 2009, 2010 and 2011 in the University of Benin, Nigeria to determine influence of NPK fertilizer and varying cropping ratios on nutrient uptake and quality components of maize and egusi melon. Cropping ratios and application of NPK 20:10:10 fertilizer at 600 kg/ha significantly (P<0.01) enhanced the percent oil, protein, N and P in maize grains and egusi melon seeds; except for maize where cropping ratios failed to enhance these qualities relative to the sole maize. Cropping ratios influenced mostly the nutrient uptake by maize grains; while N uptake was highest in sole maize, P (2.10 kg/ha) content was lowest in sole maize. For other nutrients, that is K, Ca and Mg their contents in maize grains was enhanced due to intercropping with egusi melon thus making the egusi melon less competitive with maize for the nutrients.

Increased fertilizer rates (0 to 600 kg/ha) of the NPK 20:10:10 enhanced N and Mg uptake in maize grains in intercrop with egusi melon. The trend was different in nutrient uptake by egusi melon with respect to applied fertilizer. The less uptake of nutrients by the crop may suggest residue of same nutrients for further cultivation.