Improved crop performance and resource use efficiency of greenhouse cucumbers through optimized potassium fertigation strategies

In protected cropping systems such as greenhouses and hydroponics, fertigation aims to maximise efficiency. Potassium (K) availability and its uptake are crucial for greenhouse crop production. Although K is essential for fruit quality, yield, and enzyme activity, its management in advanced systems frequently results in reduced nutrient-use efficiency. To address this, we conducted agronomical, physiological, and post-harvest measurements as well as resource and carbon footprint analyses on Lebanese and Continental cucumber varieties grown under three K fertigation levels at 185, 370 and 512 mg l-1 in a high-tech greenhouse. High K levels led to significantly higher yield in Lebanese cucumber compared to the low K treatment, while there were no significant K treatment effects observed in the Continental variety. Net photosynthetic rates remained stable across K treatments, in both Lebanese and Continental varieties. We also observed a significant decrease in K, and calcium (Ca), but magnesium (Mg) and chlorine (Cl) were more abundant at low K supply in both Lebanese and Continental cucumber varieties. Continental cucumbers grown in low K fertigation showed greater weight loss at storage temperature of 7 °C, which was associated with significantly lower firmness values. Furthermore, increased K supply reduced water and energy use intensities per kilogram of yield compared to low K treatment, improving cucumber production efficiency. Carbon footprint analysis revealed that combining high K fertigation with renewable energy scenarios could reduce emissions by approximately 95 %, highlighting a strong synergy between fertigation management and decarbonisation strategies in protected cropping systems.