Application of Trichoderma harzianum on Cassava Peel Media as a Biofertilizer for the Growth of Tomato Plants (Solanum lycopersicum L.)

Tomato (Solanum lycopersicum L.) is an economically important horticultural crop whose productivity is frequently constrained by soil-borne pathogens and declining soil fertility. Trichoderma harzianum is a beneficial fungus that acts as both a biofertilizer and a biological control agent by enhancing nutrient availability and promoting plant growth. Although numerous studies have reported the positive effects of Trichoderma harzianum on tomato cultivation, information regarding its propagation on cassava peel and the influence of different application methods remains limited. Therefore, this study aimed to evaluate the growth-promoting effect of cassava peel-based Trichoderma harzianum on tomato plants under different application methods and dosages. The experiment was arranged in a Completely Randomized Design (CRD) consisting of five treatments with four replications. The observed parameters included spore density, plant height, number of leaves, fresh weight, and dry weight. Data were analyzed using one-way Analysis of Variance (ANOVA) followed by Duncan's Multiple Range Test (DMRT) at a 5% significance level. The results showed that cassava peel medium produced a higher spore density (3.96 × 10⁷ spores mL⁻¹) than rice medium (1.67 × 10⁷ spores mL⁻¹). Soil application of 4 g polybag⁻¹ (P2) resulted in the highest plant height and number of leaves, whereas foliar application of 4 g 100 mL⁻¹ (P4) produced the highest fresh and dry weights. Overall, cassava peel proved to be an effective alternative substrate for propagating Trichoderma harzianum, while appropriate application methods and dosages enhanced tomato vegetative growth and biomass production.