Comparative effect of boiler ash-urea mixture on soil properties, growth, and yield of Cocoyam (Colocasia esculenta)

Abstract

One major constraint in utilizing boiler ash in agriculture as fertilizer is its low nitrogen content. A field trial was conducted to evaluate comparatively the effect of integrating boiler ash with urea and two rates of NPK fertilizer on soil, growth, and yield of cocoyam Colocasia esculenta (Taro) in Iwollo, Southeastern Nigeria. The experiment was laid out in a randomized complete block design (RCBD) with three replications and five treatments which comprised of a control (no fertilizer), two levels of NPK 15:15:15 (100, 200kgha-1) combinations of two levels of broiler ash (5, 10 t ha-1) with 70 kg ha-1 urea. The plots were planted with cocoyam cormels. Data on soil properties after harvest, growth, and yield characteristics were collected and subjected to one-way analysis of variance, and significant treatments mean separated by Fisher's least significant difference at 5% level of probability. Results obtained showed that the treatments did not exert significant influence on the soil physical properties evaluated, but differed significantly (p<0.05) in pH, phosphorus, and percent base saturation. Comparatively, integrating the low level of BA (10tha-1) with 70 Kg ha-1 urea reduced soil acidity, increased soil available P, and percent base saturation but did not significantly influence growth and tuber yield of cocoyam. Application NP. K fertilizer at the rate of 200 Kg ha-1 was a higher number of cormels plant-1 (32.6), cormel yield (47.8 Mg ha-1), and corm yield (4.53 Mg ha-1). The fertilization effects of broiler ash – urea mixture at the rate applied in the study were masked by innate soil ability to supply plant-available nutrients, but significant reduction in pH and enrichment in available P suggest that the broiler ash – urea mixture may have a positive effect under more acidic and P deficient conditions.