Optimization of Rice Hull Bokashi Application Rates for Improving Soil Properties and Performance of Pepper (Capsicum spp) under Tropical Conditions in Owerri Nigeria

Food insecurity, waste disposal, soil degradation and low agricultural productivity remain major challenges in Nigeria. This work was carried out to evaluate the characteristics of fermented Rice Hull-Bokashi (RH-B) and its effects on soil and pepper (Capsicum spp.) performance. The fermentation process lasted for 12 days, during which, temperature, pH, moisture, and bulk density were monitored. Five pot treatments were tested: control, 16 t/ha bokashi, 19 t/ha bokashi, 22 t/ha and 25 t/ha bokashi. The treatments were arranged in a completely randomized design (CRD), with three replications. Chemical properties of fermented RH-B, as well as pre and post-planting soil attributes, were analyzed. Vegetative growth and yield parameters of pepper were measured. The data generated from the influence of the various treatments on soil characteristics and plant performance was subjected to Analyses of Variance (ANOVA) using SPSS. Significant means were separated using LSD at 5 % probability. Results of soil analysis after treatment application indicated that the application of bokashi significantly improved soil properties. Bulk density (BD) decreased progressively from 1.65 gcm⁻³ in T1 to 1.38 gcm⁻³ in T5, representing a 16.36 % reduction relative to the control. Moisture content (MC) increased across treatments, with the highest increase recorded in T5 (33.71 %). Soil pH improved towards neutral 5.60 in T1 to 6.17 in T5, representing a 10.18 % improved pH. Organic carbon (OC), Total nitrogen (TN) and available P increased substantially across treatments, with T5 recording 53.85 %, 38.89 % and 78.77 % increase over T1. At 6 and 8 WAP, T2 recorded the highest increase in plant height (33.56 % and 41.39 %) relative to the control (T1) while T3, T4, and T5 showed only slight increases (1.26 – 8.67 %; 13.45 % - 13.82 %,) and were not notably different from the control. At 10 WAP, plant height, leaf area, number of leaves, and branches increased substantially under T2, which recorded 37.51 %, 92.47 %, 65.99 %, and 597.01 % respectively over T1. At twelve (12) weeks after planting, plant height increased under T2 with a 40.94 % increase, number of leaves with a 47.69 % increase, leaf area with a 10.10 % increase, and stem girth with a 3.33% increase over the control (T1).