Abstract

This study aimed to explore the impact of enriching sandy loam soil (BS) with Pleurotus ostreatus Strain EM-1 spent mushroom compost (SMC) on the growth and yield of tomato (Solanum lycopersicum L.) and cowpea (Vigna unguiculata L.) crops in a screenhouse environment with an average daytime temperature of 28 ± 2°C. The SMC was added to the soil in varying proportions, ranging from 5% to 100%, while the control medium consisted of unamended sandy loam soil (BS). Over a period of 14 weeks, several vegetative parameters were assessed, including plant height, leaf count, leaf area, chlorophyll content, flower count, number of aborted flowers, pod count, pod mass, pod length, fruit count, and fruit mass. The findings indicated that the different combinations of SMC and soil, used as a bio-fertilizer, had varying effects on the growth and yield of tomato and cowpea in the screenhouse setting. Generally, plant height, leaf area, flower count, pod mass, pod length, and fruit count demonstrated improved growth at lower SMC concentrations (5-20%). Among cowpea seedlings, those treated with 5% SMC exhibited the most favourable vegetative growth and yield, while tomato seedlings performed best with 10% SMC. However, leaf area, flower count, and pod count were negatively affected at the 5% SMC concentration. Concentrations exceeding 30% SMC had a variable inhibitory effect on the assessed growth parameters. This could be attributed to the presence of high levels of micro and macronutrients such as calcium, copper, iron, potassium, magnesium, manganese, sodium, lead, phosphorus, and zinc in the substrate. Different crops have distinct nutritional requirements, underscoring the importance of understanding a crop's specific nutrient needs before applying SMC as a soil amendment.