GROWTH PERFORMANCE OF SELECTED VEGETABLES UNDER FOLIAR APPLICATION OF AN INTEGRATED BIOFERTILISER-BIOPESTICIDE AND AN INORGANIC FERTILISER

Abstract

Vegetable production is hampered by declining soil fertility, increasing pest attacks, and over-reliance on costly inorganic fertilisers. While integrated biofertiliser–biopesticide products present a potential sustainable alternative, empirical evidence pertaining to their effectiveness is limited. The study tested three treatments (T0=unfertilised control, T1=Integrated biofertiliser-biopesticide, and T2=Inorganic fertiliser) on the growth and yield of eggplant, green pepper, and cabbage. The experiment was laid out as a Randomized Complete Block Design (RCBD) with three replicate blocks. Foliar application of fertilisers was done twice a week for 10 weeks, and plant height, leaf length, number of leaves, number of branches, fruit diameter, and diameter of cabbage head were monitored. Analysis of variance was carried out on data collected at Weeks 1, 2, 4, 6, 8, and 10 using the model Value ~ Rep + Treatment, with 2 degrees of freedom each for Replication and Treatment, and 4 for Error. Trends across weeks were summarised graphically and quantified by quadratic regression. The integrated biofertiliser–biopesticide (T1) consistently produced the highest vegetative growth and reproductive performance across all three crops, outperforming inorganic fertiliser (T2) and unfertilised control (T0). The strongest effects were at week 10 for eggplant fruit diameter (F = 36.25, p = 0.003), green pepper fruit number (F = 18.20, p = 0.010), and green pepper plant height (F = 138.10, p = 0.0002).Quadratic regression identified three growth patterns: accelerating curves for delayed reproductive traits (fruit production), saturating curves for vegetative traits nearing maturity (plant height, leaf length, and branch number), and dome-shaped curves for cabbage leaf number, which peaked at weeks 6–7 before declining due to leaf senescence during head formation. This model outperformed the linear model, increasing the mean R² from 0.817 to 0.928 across 45 fits. Emergence of pests was noted in cabbages under T0 in weeks 8-10. Thus, the integrated biofertiliser-biopesticide can be a potential substitute for scarce, costly, and harmful inorganic fertilisers to boost vegetable productivity.