Agronomy (Oct 2020)
Methods of Silicon Application on Organic Spring Wheat (<i>Triticum aestivum</i> L. spp. vulgare) Cultivars Grown across Two Contrasting Precipitation Years
Abstract
The potential of silicon used in two forms, two methods and three cultivars of spring wheat cultivated under organic farming conditions is high, as it helps plants to alleviate abiotic stresses. The research hypotheses of paper were the assumptions that the effectiveness of silicon may differ not only by the form of silicon and the method of its application, but also by the variety of common wheat and different water conditions in the soil during the growing season. These hypotheses were confirmed. The aim of this study was to determine the effectiveness of liquid and powder silicon forms and different methods of application in three cultivars (Harenda, Serenada and Rusałka) of spring wheat organically grown under a specific field experiment in water stress vs. no stress conditions. The water stress of plants was assessed on the basis of the sum of precipitation in the winter–spring and vegetation season in each year. The differences in water availability for the plants in the experimental years were confirmed. Silicon (Si) was used for seed dressing and/or for leaf spraying. In the first case, the powdered form of Si was used at a dose of 0.5 kg/100 kg of seeds; it was used together with the liquid form at a dose of 0.5 L/100 kg of seeds, and in the second, the liquid form of Si was used at a dose of 0.5 L per 200 L of water per hectare; spraying was carried out at the following plant development stages: three tillers detectable, the first node and the flag leaf. The application of Si positively influenced the wheat yield depending on the method of Si application, wheat variety and severity of water stress. The cultivar Harenda was more susceptible to lower water content in the soil than the cultivars Rusałka and Serenada. Under conditions of water stress, the use of Si slowed the development of young Harenda plants, but ultimately, the variety increased its grain yield to a greater extent than the other two varieties. The lowest weight of a thousand grains (TGW) was found in the Harenda variety; however, Si treatment improved this parameter. Si increased the yields of the three wheat varieties, and the highest were harvested in plots with combined Si treatments. The yields of the Rusałka and Serenada cultivars on these plots were 14 to 28% higher compared to the control. Harenda was the least fertile variety, but it increased its yield more than the other two varieties. This variety increased its yield in 2018 (year of average rainfall) by 26% from 2.92 to 3.94 tons per hectare, and in 2019 (a year of drought) by 42% from 1.66 to 2.87 tons per hectare. It can be concluded that Si improves the wheat yield, and its efficiency depends on the scale of water stress, the method of application and the variety. The simplest and most adaptable method of Si application is seed dressing and has prospects for wider application, especially in organic farming.
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