Cucumber production using natural biostimulant and nanofertilizer: insights from oak leaf extract and potassium nanofertilizer

Cucumber is a widely cultivated vegetable crop valued for its nutritional and economic importance. However, the intensive use of conventional fertilisers can negatively affect soil health and the environment. Therefore, developing efficient nutrient management strategies that maintain productivity while reducing dependence on chemical inputs remains an important research focus. Despite growing interest in plant-based biostimulants and nanofertilisers, limited information exists on their combined effects on cucumber growth, yield and quality. This study evaluated the individual and interactive effects of oak leaf extract (OLE) and potassium nanofertiliser (KNPs) on cucumber performance under greenhouse conditions. Plants were treated with OLE (3 and 6 g/L) and KNPs (300 and 600 mg/L), applied alone and in combination. Growth traits, yield components, photosynthetic pigments, biochemical quality parameters, antioxidant activity and mineral nutrient contents were measured, and multivariate analyses were performed. The combined application, particularly OLE at 3 g/L with KNPs at 600 mg/L, significantly enhanced root development, photosynthetic pigments, nutrient uptake, fruit quality and total yield compared with the other treatments. Strong positive associations were observed among yield, nutrient status and physiological traits. These findings indicate that integrating plant extracts with nanofertilisers can enhance cucumber productivity and quality while promoting efficient, environmentally friendly vegetable production.