Abstract:
We conducted a study to determine the response of Late Valencia sweet orange to organic and inorganic fertilizer application for two seasons in the semi-deciduous forest agro-ecological zone of Ghana. The experiment which was conducted in a randomized complete block design with four replications consisted of six treatments: 9 t/ha oil palm empty fruit bunches (EFB); 4t/ha Poultry manure (PM); NPKZn (90kg/ha N, 60kg/ha P, 80kg/ha K and 4.8kg/ha Zn); 4.5 t/ha EFB+NPKZn (45kg/ha N, 30kg/ha P, 40kg/ha K and 2.40kg/ha Zn); 2t/ha PM + NPKZn) (45kg/ha N, 30kg/ha P, 40kg/ha K and 2.40kg/ha Zn) and Control. In the 2019 harvest season, the treatment PM+NPKZn recorded the highest yield of 14.71t/ha while the control recorded the least yield (6.37t/ha). In the 2020 harvest season, fruit yield ranged from 17.3 t/ha with the NPKZn treated plots 28.8t/ha with the EFB treated plots to. Economic analysis shows that for the five fertilizer application treatments, the highest benefit/cost ratio was attained with the EFB treatment for the two harvesting seasons combined. Fertilization did not significantly affect leaf nutrient content 253 days after application. However, leaf N and K contents were generally higher 253 days after fertilizer application than the initial levels while P level did not change. Soil analysis 253 days after nutrient application showed an increase in total N, OC and available P while pH level decreased. The study suggests the need for farmers to adopt the use of crop residues for maintaining soil fertility of citrus orchards for improved fruit production.