EVALUATING THE INFLUENCE OF BIOGAS SLURRY ON AGRONOMIC PERFORMANCE OF TOMATOS AND SOIL FERTILITY UNDER OPEN FIELD CONDITIONS
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2026
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Tomato (Solanum lycopersicum L.) is among the most economically important horticultural crops in Uganda, contributing significantly to household income, nutrition, and food security. However, open field tomato production remains constrained by declining soil fertility and prohibitively high costs of inorganic fertilizers. This study evaluated the influence of biogas slurry (BGS) on agronomic performance of tomatoes under open field conditions at Busitema University Demonstration Farm, Busia District, Eastern Uganda. A Randomized Complete Block Design (RCBD) with four treatments biogas slurry, chemical fertilizer (NPK 17:17:17), cow dung, and an unfertilized control replicated twice was employed over 42 days. Vegetative parameters (plant height, stem diameter) and reproductive parameters (number of flowers, number of fruits per plant) were measured. Soil organic matter and organic carbon were analysed before and after treatment application using the Walkley-Black method. Data were subjected to one-way Analysis of Variance (ANOVA) in Microsoft Excel. Results indicated that while vegetative growth differences among treatments were not statistically significant (p > 0.05), both biogas slurry and NPK consistently outperformed cow dung and the control numerically. Reproductive parameters showed statistically significant treatment effects, with NPK recording the highest flower and fruit counts, followed closely by biogas slurry. Soil fertility analysis revealed highly significant increases in soil organic matter under organic amendment treatments, particularly cow dung and biogas slurry (F = 129.98, p = 0.000193). These findings demonstrate that biogas slurry is a viable, sustainable, and cost-effective alternative or complement to chemical fertilizers for smallholder tomato production in Uganda.