Interactive Effects of the Potassium and Nitrogen Relationship on Yield and Quality of Strawberry Grown Under Soilless Conditions

K and N are the nutrients with the highest influence on yield and fruit quality. From this perspective, the aim of this study was to determine the effect of N as NO(3)(−), K(+) and their interactions on the yield and quality of strawberries grown under soilless conditions. A solution comprised of micronutrients based on an amended Steiner’s Universal Nutrient Solution was mixed with 4 levels of K(+) (5, 7, 9 and 11 mol m(−3)) and 3 levels of NO(3)(−) (9, 12, and 15 mol m(−3)) to obtain 12 treatments. The results suggest that 15 mol m(−3) of NO(3)(−) in the nutrient solution produced the highest yield, but fruit with low nutraceutical quality. On the other hand, 11 mol m(−3) of K(+) in the nutrient solution produced the highest yield and fruit with the best nutraceutical quality. The ionic concentration of the Universal Steiner’s Nutrient Solution proved to be the best nutritional option to maximize the yield and nutraceutical quality of strawberry fruit. The increase in NO(3)(−) concentration in the nutrient solution produced a higher yield of strawberries, while a higher concentration of K(+) improved fruit quality, thus reaffirming the significance of nutrients within the plant functioning of this crop.