Aim of the study:
The aim of this study was to evaluate the yield and gross margin analysis of supplementary irrigation (SI) and rainfed systems of Chili pepper and Okro in northern Ghana.

Material and methods:
The study was a 4×2×2 factorial design with 3 replications, using the Randomized Complete Block Design (RCBD). The research treatments were; 4 levels of NPK fertilizer, rainfed and SI. NPK was applied 0, 150, 200, 250 kg/ha, and 0, 100, 150 and 200 kg/h for the okro and chili pepper respectively.

Results and conclusions:
Chili pepper produced a yield of 2067.41 kg/ha in SI and 1441.60 kg/ha in rain-fed. Okro gave a yield of 1415.70 kg/ha whereas 1135.10 kg/ha was obtained from rainfed. At a cost of USD 1324.80/ha and USD 1146.70/ha for SI and rain-fed respectively on chili pepper, a gross margin (GM) of USD 516.40/ha and USD 137.00 was attained for SI and rain-fed. In the case of okro, a cost of USD 1540.20/ha and USD 1362.20 was invested in SI and rain-fed and a gross margin (GM) of USD 254.00/ha and USD 76.20/ha was attained for SI and rain-fed system respectively. The cost-benefit ratio (BCR) for SI okro was estimated at 1.16 and 1.06 for rainfed cultivation, whereas 1.39 and 1.12 were the BCR for SI and rainfed chili pepper. In conclusion, SI gave a higher GM capable of covering production costs compared to rain-fed system. Farmers experiencing drought are advised to use SI with appropriate management practices to increase crop productivity.