Profitability of Fertilizer Use for Citrus Production in Teso Sub-Region, Eastern Uganda

Citrus is an important commercial crop in Uganda, especially the Eastern region. However, in spite of the increasing regional demand, citrus productivity is still low, attributed to pest and diseases, soil moisture stress, and low soil fertility, among others. Efforts to improve soil fertility are limited by inadequate supply of organic fertilizers due to competing demands. In addition, there is inadequate information on inorganic fertilizer requirements for citrus production in Uganda. The objective of this study was to develop optimum fertilizer recommendations for citrus production for Eastern Uganda. The study was conducted in Teso region, Eastern Uganda. Fertilizer (NPK, 17:17:17) was randomly applied to Hamlin, Valencia and Washington varieties with fertilizer and variety factorially arranged for each farm and citrus age range, replicated three times. Fertilizer rates were 0, 139, 278 and 556 kg NPK/ha for the 4 - 7-year old trees, and 0, 278, 556 and 1111 kg NPK/ha for the mature (8 years and above) trees. For a given variety, each fertilizer rate was applied onto three representative trees per farmer, six farmers per district. Results showed that yields and net profits were highest for variety Hamlin, and nearly the same for varieties Washington and Valencia. Fertilizer application increased fruit yield and profits for both the 4 to 7-year and 8 and above-year-old trees, with highest yield and profitability values observed at 556 kg NPK/ha. These results suggest applying 556 kg NPK/ha to citrus per year as an optimum fertilizer rate for citrus production in Teso region. The fertilizer should be applied in smaller splits of 800, 600, and 600 grams per tree, applied in April, June, and August.