EFFECTIVENESS OF RICE-HUSK BIOCHAR IN SUSTAINABLE ARABICA COFFEE PRODUCTION IN SOUTH EASTERN UGANDA

The study aimed at determining the effectiveness of rice-husk biochar in improving the growth and yield of Arabica coffee in southeastern Uganda. Two experiments were run from January 2023 to July 2024, on mature coffee and on coffee seedlings. The mature coffee experiment involved applying plain and fortified biochar on coffee at 0, 300, 600, 1200 and 2400 g/tree in Bulambuli and Kween Districts. The coffee seedlings trials involved applying plain and fortified biochar to polypots at varying biochar-to-soil ratios (0, 25, 50, 75, and 100%) before placing the coffee seedlings. The seedlings were watered daily, after two days and after three days. Results from the mature coffee showed that soil organic matter and nitrogen increased with application of biochar, especially the fortified. However, below biochar application rate of 2400g/tree, P and K availability reduced with increase in fortified biochar, but increased with increase in plain biochar. Fortified biochar supported more vegetative growth than plain biochar at 1200–2400 g/tree, though yield differences between the two were not significant. However, incremental returns on investment were higher for plain than fortified biochar. Watering the seedlings at two-day interval promoted better root and leaf development than daily watering.