Quality Implications of Marketed Brands of NPK 20:10:10 Fertilizer on Maize (Zea mays) Performance and Residual soil Chemical Properties

Abstract

Anecdotal evidence in Nigeria establishes that there is limited enforcement of fertilizer standards and high prevalence of poor-quality fertilizers. A field study was initiated at the Research and Demonstration Farms of Enugu State Polytechnic Iwollo, Ezimo Campus and University of Nigeria Nsukka, to comparatively evaluate the effects of three brands of NPK 20: 10:10 fertilizer locally called Federal, Ebonyi, and Kano on maize performance and soil chemical properties. The fertilizers and a control were laid out in a randomized complete block design (RCBD) with three replications. The fertilizer samples were analyzed for N, P, K contents while residual soils were analyzed for pH, OM, N, P, and K. Hybrid maize (Oba super II) were grown in both locations. Data were collected on their growth and yield traits. Results revealed that, contrary to the labeled nutrient grade -NPK 20:10:10 on the fertilizer brands, they were, NPK 15:8:7; 14: 8:7 and 7:7:8for Federal, Ebonyi and Kano respectively. The difference in nutrient grades reflected in the performance of the plants as Federal significantly (p<0.05) produced plants that were superior in height (123.3 cm), stem girth (7.6cm), number of leaves (13), biomass weight (370g plant^-1), cob weight (146.2g plant^-1), grain weight (4.63tha ^-1) and 100 seed weight. The fertilizer brands did not differ significantly with control in residual soil chemical properties. The study highlights the need for a brand specific test and recommendation of inorganic fertilizers prior to application and for fertilizer regulatory agencies to intensify efforts in enforcing standards.