Effectiveness of Coconut Shell Biochar Soaking Duration and Phonska Plus Dosage (15 15 15) in Increasing Soil Fertility, Growth, and Yield of Shallots

This study investigated the effect of compost tea soaking duration in biochar and Phonska Plus fertilizer dosage on soil fertility and shallot growth. A greenhouse experiment using a factorial Completely Randomized Design was conducted with four soaking durations (0, 12, 24, and 36 hours) and four fertilizer doses (100, 200, 300, and 400 kg/ha). Results showed that soaking duration significantly improved plant growth, yield components, soil pH, organic carbon, available N, P, K, and fungal colonies. Fertilizer dosage also significantly affected growth, yield, and soil fertility. While no interaction effects were observed on yield and fungal colonies, interactions occurred for growth and some soil parameters.