Effects of NPK single fertilizers on relative growth performances of two cycles of maize (Zea mays L.) grown in a degraded soil of Southwest Nigeria

The balanced use of inorganic amendments to enhance effective crop production for developing world economies like Nigeria is paramount to achieve her Millennium Development Goals (MDGs) for its teeming population. Thus this study was carried out to assess the relative growth performances of a major food crop under different regimes of fertilizer application. Field and Green House experiments were carried out to assess the relative growth performances of two Cycles of Zea mays L. (LNTP-W C0 and C3) used as test crops for the amendment of degraded soil using N, P and K single fertilizers. The single fertilizers (treatments) used were Urea, Single Super Phosphate (SSP) and Muriate of Potash and the study was carried out in the Department of Botany, University of Ibadan, Nigeria. The experiment consisted of 4 treatments applied at 2 levels (C0 and C3) and replicated three times in a Completely Randomized Design (CRD) to give a total of 48 experimental units. The application of Nitrogen (N) was done at four levels (0, 30, 60 and 90 kg haG1), while the Phosphorous (P2O5) and Potassium (K) were applied at a constant rate of about 60 kg haG1 for all the pots except for the experimental control pots. The design was adopted for both Green House and Field experiments. The results from the study showed that C3 performed better than C0 in Field and Green House experiments with respect to their relative performances of the growth parameters; plant height (cm), stem diameter (mm), number of leaves, leaf length (cm) and leaf width (cm) measured within the Pre-flowering period of 8 weeks. The treatment combination of 90 kg haG1 N, 60 kg haG1 P and 60 kg haG1 K gave the best performance in this study. The study also revealed that the growth rate of the maize plant was directly proportional to the level of N applied with constant levels of P and K providing the basis for developing optimum NPK fertilizer level for the amendment of degraded soil for higher productivity using maize with tolerance to low soil Nitrogen. The study showed that more derelict soils can be put to good use with the appropriate level of NPK Fertilizer application optimum for the right crop, thus aiding the use of hitherto abandoned degraded land and putting more land under cultivation.