Beneficial effects of using silicon for organic greenhouse cucumber
2018
Dorais, M. | Theriault, M.
It has been reported in the scientific literature that silicon (Si) applications may alleviate abiotic and biotic stresses for a number of important crops such as cucumber. They also improve nutrient imbalance, increase photosynthetic activity, and influence biomass accumulation in fruit. However, most of the studies were conducted using soluble forms of Si (e.g., silicate of potassium or sodium) that are not allowed under organic farming. On the other hand, wollastonite is a natural source of calcium inosilicate mineral (CaSiO(3)) that can be used for organic farming. Thus, the goal of this study was to compare the effects of three application rates of wollastonite (2, 4 and 8 g L-1 soil), a soluble source of K(2)SiO(3) and a control (without Si amendment) on plant growth, fruit production and fruit quality. The experimental design was a randomized complete block design with 8 replicates. Cucumber plants (Cucumis sativus ‘Verdon’) were grown in 7.3-L containers filled with a customized organic peat-based growing media. Growth parameters, chlorophyll content, Si leaf and fruit content, mineral content, productivity and fruit quality were evaluated. Our results showed that cucumber leaves of plants exposed to Si had 1.74 to 10.2 times more Si than control leaves, older leaves having 2.8 to 6.0 times higher Si than younger leaves. The leaf Si content increased with the application rates of wollastonite. The Si content of Si-treated fruits was very low, ranging from 0.04 to 0.14%, while no Si was detected in control fruits. Compared to the control plant, the 8 g L(-1) wollastonite treatment increased the total growth by 6.5%. However, Si treatments did not have any significant effect on the total and marketable number of fruit harvested per plant or on fruit weight. The visual aspect of the fruit (peel and flesh color) and the fruit content in Brix, titratable acids, vitamin C and total phenol were not significantly (p<0.05) affected by Si treatments. We can conclude that the leaf accumulation of Si by cucumber when Si was supplied as wollastonite was as efficient as soluble K(2)SiO(3). Although no significant effect of Si was observed on crop productivity and fruit quality, the use of wollastonite within peat-based soil constitutes a good tool to increase plant resilience under organic farming.
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