EFFECT OF SUPPLEMENTARY IRRIGATION AND FERTILIZER LEVELS ON GROWTH AND YIELD OF CHILI PEPPER (Capsicum annuum L.) AND OKRO (Abelmoschus esculentus L.) IN NORTHERN REGION OF GHANA

Abstract

Soil moisture and fertility are the most predominant factors influencing crops productivity. The rainfall pattern in northern Ghana is often not reliable and hence leads to drought during the wet season. This has been reported to have a major effect on vegetable production. Therefore, rainfall needs to be supplemented by irrigation to fully utilize the potential of the agricultural soils and improve yield. The main objective of the study was to assess the effect of supplemental irrigation and fertilizer (nitrogen, phosphorus and potassium (NPK 15-15-15)) levels on Chili pepper and Okro growth and yield. The experiment was conducted at Nyankpala in the Guinea Savannah Agro-ecological zone of Ghana during the 2022 wet season. The study was a 4 x 2 x 2 factorial experiment laid out in Randomized Complete Block Design (RCBD) with 3 replications. The treatments included two (2) crops (Chili pepper and Okro), four (4) levels of inorganic fertilizer (0 kgha-1, 100 kgha-1, 150 kgha-1 and 200 kgha-1in Chili pepper and 0 kgha-1, 150 kgha-1, 200 kgha-1 and 250 kgha-1 in Okro), rainfed (RF) and Supplemental Irrigation (SI) using spray tubes system. The results showed that, crop water requirement of Chili pepper and Okro were estimated at 459.90 mm and 263.0 mm respectively. The main effect of SI and 200 kgha-1 fertilizer level recorded the highest plant height in both Chili pepper and Okro respectively. SI and 200 kgha-1 and SI and 250 kgha-1fertilizer level produced the highest number of leaves in Chili pepper and Okro respectively. SI recorded the highest number of flowers per plant in Chili pepper (12.00), leaf area (16.50 cm2), Leaf Area Index (LAI) (0.00461) of Chili pepper, LAI (0.00824) of Okro, fruit diameter of Okro (34.90 mm) and number of fruits of both crops. Fertilizer application at 200 kgha-1 recorded the maximum leaf area (86.80 cm2) in Okro. Fertilizer application at 200 kgha-1recorded chlorophyll content of 71.60 spads in Okro whilst SI recorded the highest chlorophyll content of 69.50 spad in Chili pepper. SI + 250 kgha-1fertilizer dosage (51.73 spad) recorded the highest chlorophyll content of 51.73 spad in Okro. SI + 200 kgha-1 fertilizer level produced the highest biomass in Chili pepper and Okro. The SI treatment produced the maximum yield of 3.51 tons/ha in Chili pepper and the maximum yield of 1.80 tons/ha in Okro. A Gross Margin (GM) of Ghȼ 7,539.30/ha and Ghȼ 3,707.90/ha in SI Chili pepper and Okro respectively. Under rainfed, GM of Ghȼ 2,000 and Ghȼ 1,112.40 for Chili pepper and Okro respectively. Overall, the application of fertilizer level at 200 kg/ha at the initial stage of the crop and SI spray tube irrigation system is recommended for maximum Chili pepper and Okro growth, yield and gross margin. There was no significant difference in the crop water productivity of SI and rainfed crops.