Effects of NPK Fertiliser (15-15-15) on the Growth Performance of Three Arable Crops Grown on Degraded Kaolin Mined Soil in Abia State, Southeast Nigeria

Experiments were carried out in the Nursery of the Department of Forestry and Environmental Management, the Michael Okpara University of Agriculture, Umudike in Abia State during 2016 and 2017 cropping seasons to determine the effect of NPK fertilizer on the growth performance of three selected crops, Zea mays, Abelmoschus esculentus and Vigna unguiculata grown on a derelict kaolin mined soil. The experiment comprised of treatment pots which has three rates of fertilizer on the kaolin soil each (kaolin soil +NPK (40 kg), kaolin soil + NPK (30 kg) and kaolin soil + NPK (20 kg) kaolin soil with zero treatment (Control 2) and a control 1(un-mined) soil, it was replicated three in Complete Randomized Design (CRD). Parameters assessed include Plant height (cm) and the number of leaves weekly for six (6) weeks. Data were analysed using ANOVA at p< 0.05. The result obtained showed that growth performance of the test crops was positively affected by NPK treatment based on the quantity applied with the highest recorded height (16.50) and the number of the leaf (11.27) in Kaolin mined soil combined with 40 kg of fertilizer when compared with the control. Plant height obtained with various fertilizer treatments were in the order: 16.50>15.99>14.65 and 11.27>10.20>9.01 for the number of leaves. The result of the macro element levels in the plants showed that the nutrient uptake and accumulation were enhanced by both NPK fertilizer and the quantity added with the highest level of nutrient on the plants obtained in Kaolin soil combined with 40kg of NPK fertilizer. The study showed that kaolin mined degraded soil can be put into good use with the appropriate concentration of fertilizer treatment, thus putting more degraded land under agricultural production and ensuring food security is developing country like Nigeria. The study further suggests a sensitization program for farmers on the appropriate concentration of inorganic fertilizer to be applied to their farmers to avoid pollution.