A comparative study between the efficacy of fertigation and spraying procedures in terms of the content of Cadmium (Cd) and Arsenic (As) in greenhouse cucumber.

A comparative study between fertigation and spraying procedures in terms of the status of Cadmium (Cd) and Arsenic (As) in greenhouse cucumber was conducted as a two-factor split plot based on a randomized complete block design with three replications at the Soil and Water Research Institute, Karaj, Iran in 2023. The main and sub-factors were respectively fertigation and spraying that were used in two levels [the maximum permissible concentration of Cd and As in granular triple super phosphate fertilizer (25 ppm Cd and 50 ppm As) and the minimum permissible concentration of these metals in granular triple super phosphate fertilizer (5 ppm Cd and 5 ppm As)]. Spraying was done in three modes (spraying of leaves, leaves and fruit, and fruit). On average, the results showed that the order of the concentration of Cd in plant tissues (DW) was as leaf (0.284 mg/kg) > fruit peel (0.102 mg/kg) > fruit peel + flesh (0.054 mg/kg) > fruit flesh (0.044 mg/kg). This order for As was as leaf (0.608 mg/kg) > fruit flesh (0.127 mg/kg) > fruit peel + flesh (0.109 mg/kg) > fruit peel (0.072 mg/kg). Based on the measurements, the spraying procedure accumulated more amounts of Cd and As in the fruit (i.e., peel + flesh) than the fertigation procedure. In general, it is concluded that under soilless culture, the status of heavy metals in plant tissues of greenhouse cucumber is related to the nature of the metal, the organ exposed to the metal, and the fertilization procedure. Because there is the risk of contamination of vegetables grown in the areas fertigated and sprayed with poor-quality nutrient solutions in terms of the content of heavy metals, the frequency of fertigation and spraying needs to be monitored continuously for the quality of the vegetables cultivated in greenhouses.