Leaf physiological attributes and root productivity of two radish cultivars as influenced via low tunnel plastic sheeting and silicon foliar application under cold stress

This study aimed to assess the impact of low plastic tunnels integrated with potassium silicate spraying on the physiological traits and root productivity of two radish cultivars under cold stress conditions. A field experiment was performed on a private sector farm in Albuhidari, Al-Najaf governorate, Iraq, during the autumn season of 2023. The experiment was conducted in a split-split plot design using Randomized Complete Block Design (RCBD) with three replicates, testing the effects of three factors: growth conditions (open field versus plastic tunnels) designated as the main plots, cultivars (red versus white) assigned as subplots and doses of silicon spraying (0, 400, 600 mg L-1) assigned as sub-subplots. The results showed that plastic sheeting significantly improved total chlorophyll in leaves, nitrogen and potassium percentages in the leaves, total plant dry matter and root yield compared to the open field. The red cultivar outperformed the white cultivar in chlorophyll content, potassium percent, total plant dry matter and yield. Furthermore, silicon spraying enhanced the studied traits, as total chlorophyll, total dry matter and root yield gradually increased with higher silicon concentrations. Moreover, the triple interaction of plastic tunnels, red cultivar and silicon at 600 mg L-1 was the best regarding all attributes except phosphorus percentage in leaves. These results suggest that plastic sheeting combined with silicon spraying represents an effective strategy for improving radish productivity under cold stress.