Response of Late Valencia Sweet Orange (Citrus Sinensis (L.) Osbeck) to Fertilization on Acrisols of the Semi-Deciduous Forest Agro-Ecological Zone of Ghana

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: (1) 9 t/ha oil palm empty fruit bunches (EFB); (2) 4 t/ha poultry manure (PM); (3) NPKZn (90 kg/ha N, 60 kg/ha P, 80 kg/ha K and 4.8 kg/ha Zn); (4) 0.5 EFB (4.5 t/ha) + 0.5 NPKZn (45 kg/ha N, 30 kg/ha P, 40 kg/ha K and 2.40 kg/ha Zn); (5) 0.5 PM (2 t/ha) + 0.5 NPKZn (45 kg/ha N, 30 kg/ha P, 40 kg/ha K and 2.40 kg/ha Zn) and (6) Control. In the 2019 harvest season, the treatment PM+NPKZn recorded the highest yield of 14.7 t/ha while the control recorded the least yield (6.4 t/ha). In the 2020 harvest season, fruit yield ranged from 17.3 t/ha with the NPKZn treated plots to 28.8 t/ha with the EFB treated plots. Economic analysis showed 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 nitrogen (N) and potassium (K) contents were generally higher 253 days after fertilizer application than the initial levels while phosphorus (P) level did not change. The study suggests the need for farmers to adopt the use of organic wastes as a soil fertility management practice for citrus while at the same time ensuring timely control of diseases to reduce fruit drop and improve fruit yield.