Fish effluent contains high concentration of nutrients such as nitrogen, which if used as a fertilizer, is effective on the health and yield of potatoes. Pot experiments were factorial with a completely randomized design with three replications for three years. The investigated factors consist of irriga- tion of two kinds (IF: irrigation with fresh water and IE: irrigation with fish effluent), and sprinkling the leaves of the plant in four levels (SBE: before applying fish farm effluent to the leaves, they were sprinkled for ten minutes with fresh water, SAE: after applying fish farm effluent to the leaves, they were sprinkled for ten minutes with fresh water, SBAE: The leaves were sprinkled with fresh water for ten minutes both before and after applying the fish farm effluent to them, or were not sprinkled (SN)). The result demonstrates that the highest yield (565 g pot-1) was achieved with irrigating by fish effluent and the lowest yield (486 g pot-1) was with irrigating by fresh water. According to the results, pre-sprinkling and post- sprinkling (SBAE) led to the highest photosynthesis, chlorophyll a, total chlorophyll, and carotenoid content. The combination of pre and post sprinkling leaves with fresh water (SBAE) suppressed the nitrate concentra- tion in potato tuber by 12.76% compared to condition that the leaves were not sprinkled at all (SN).
