ABSTRACT

A field experiment was carried out to investigate the mitigating effect of the application of copper nanoparticles on Vigna unguiculata grown in soil treated with various concentrations of Nacl. The experiment consisted of control and three different treatments of sodium chloride (NaCl) namely, 0.625g/l, 1.25g/l and 2.5g/l mimicking a saline environment and three different concentrations of copper nanoparticles namely, 5%, 25% and 50% were administered. Each treatment had four replicates making a total of 52 bags. Five seeds were planted in each bag, and germination readings were taken for seven days. Each bag was keyed with the following letters: A – Control without NaCl and nanoparticles, B, C, D and E for 0.625g/l NaCl only, 0.625g/l NaCl + 5% CuNP, 0.625g/l NaCl + 25% CuNP and 0.625g/l NaCl + 50% CuNP respectively. F, G, H and I represent same concentration of copper nanoparticles for 1.25g/l NaCl treated soil. J, K, L and M also represent same concentrations of copper nanoparticles for 2.5g/l NaCl treated soil. At the end of germination studies, copper nanoparticles were applied via foliar spray and readings for plant height, stem girth and number of leaves were taken weekly for 5 weeks. At the end of the germination studies, control, 0.625g/l, 1.25g/l and 2.5g/I recorded 80%, 75%,75% and 40% respectively. The effect of Sodium Chloride (NaCl) retarded the germination of cowpea seeds. At the end of the experiment, treatments E had the highest height compared to all other treatments with values of 55.25±15.5cm for 0.625g/l treated soil and H had the highest height of 22.30±3.25cm compared to F (21.32±1.85cm), G (17.65±1.98cm), I(20.60±1.19cm) and control (16.00±1.32cm) respectively which revealed an enhancement in height of plants treated with copper nanoparticles compared to control. The values recorded for girth and microbial analysis showed a positive effect of copper nanoparticles on the treated plant compared to control except of the number of leaves.