The Effect of Foliar Application of Silicon, Calcium, and Potassium Fertilizers on Yield and Some of the Agronomic and Physicomechanical Traits of Hordeum Vulgare

Food security is one of the basic needs of any society. Studies have been conducted on the foliar application of elements, especially silicon, calcium, and potassium, to reduce the adverse environmental effects on the physico-mechanical properties of cereals and improve their growth and development in order to maintain food security. Lodging, which is caused by a decrease in the mechanical properties of the plant stem's flexural strength, is characterized by bending or fracture that changes the angle of the grain stem from the vertical position. Due to the important factors involved, an important aspect of performance is directly and indirectly related to the occurrence of fungal diseases and nutrient-related issues affecting the physico-mechanical properties of the plant, such as flexural strength. The efficacy of silicon, calcium, and potassium in addressing these concerns is notable.

This research was conducted at the research farm of the Faculty of Agriculture, Shahroud University of Technology, located in Bastam. The seeds of the Reyhan cultivar, a high-yielding and early spring-type barley plant suitable for regions with mild winters and short springs, were used in this study. Planting operations followed agricultural principles, and irrigation was carried out using atmospheric and ridge methods. The first irrigation took place after planting, and subsequent irrigations were performed aeight-day intervals. Harvesting was done manually at the end of the growing period, specifically 115 days after planting.The experiment followed a factorial design and utilized a randomized complete block design with three replications. On July 11 (115 days after planting), a harvest sample measuring 50 cm2 was taken from each experimental plot, accounting for the margins, to determine the yield.For the barley stem bending test, a three-point bending test was conducted using a material testing machine. The probe applied a loading speed of 5 mm.min-1. A specially designed jaw was used for the barley stem cutting test, taking into consideration the characteristics of the barley plant. The incision test was performed on the second median, and the loading speed was set at 20 mm.min-1.

The main axial stem serves as a storage organ, supporting the filling grains through stock re-transference. A desirable trait is having a higher dry weight in the stem. Among the treatments, foliar application of 6 mM calcium chloride, along with sodium silicate at all three levels and spraying with 12 mM silicon at concentrations of 150 and 300 mg.L-1, showed statistically superior results.Stem diameter is an important attribute related to plant strength, stability, resistance to lodging, and certain fungal diseases. The control plants had a stem diameter of 2.63 mm, which significantly improved with the treatment compounds. Barley stem wall thickness increased significantly with both 150 and 300 mg.L-1 levels of calcium chloride, combined with all three levels of sodium silicate spraying. These factors play a role in determining the ultimate photosynthetic destination, as well as the efficiency and economic production of the target seed cultivar or crop.The results indicated a significant increase in grain yield when simultaneously applying 10 mg.kg-1 silicon with 6 mM calcium chloride, showing a 65% improvement compared to the control. Treatment with three potassium sulfate variations, combined with either 6 or 12 mM calcium chloride, or 12 mM calcium chloride alone, enhanced the flexural strength of the stem by 75%, 60%, and 62%, respectively. Among the treatment compounds studied, the shear strength of barley stems ranged from 2.63 MPa to 5.43 MPa. Plants treated with sodium silicate at concentrations of both 150 and 30 ml.L-1, in conjunction with 6 mM calcium chloride foliar application, exhibited higher shear strength compared to other treatments.

This study demonstrated the tripartite effect of the treatments. The treatment composition derived from a surface area of 300 ml.L-1 of sodium, combined with 6 and 12 mM calcium chloride without potassium sulfate, had the greatest impact on flexural strength and stem diameter.