Rate and Application Time of Plant Available Silicon on Winter Wheat Yield and Quality.

Many studies throughout the world has shown that various crops have positively responded to silica (Si) application in terms of plant health, nutrient uptake, yield and quality. Some of the noted silica-related benefits include: i) improved plant nutrient uptake and utilization, increased nitrogen and phosphorus use efficiency, thus, lower rates of nitrogen (N), phosphorus (P), and potassium (K), in combination with Si, may result in higher yields and better quality, ii) improved tolerance to drought and disease, and pest pressure, iii) improved plant stand and straw strength. Although not considered an essential element for plant growth, Si has been recently recognized as a “beneficial substance” or “quasi-essential”, due to its important role in plant nutrition, especially notable under stress. This study was established in the fall of 2015, at two locations at University of Idaho (UI) Parma Research & Extension Center to evaluate silica (Si) effect on wheat growth and development, grain yield and grain quality. Winter wheat (var. Stephens) was planted at 155 kg ha-1 seeding rate. Following preplant soil test, all plots were treated at seeding with N, P, and K to achieve UI recommended levels for wheat. Research plots were treated with Si (0-0-5) by Montana Grow Inc. (Bonner, MT). Wheat was irrigated using sprinkler irrigation system throughout the season. Two application times - emergence and Feekes 5 - and three application rates - 560, 280, and 140 kg Si ha-1 - corresponding to 100, 50, and 25% of manufacturer-recommended rates. Following Si application, plant height was measured in each plot. Whole plant above ground biomass samples were collected immediately prior to and two weeks after Si application. Biomass samples were analyzed for N, P, K, and Si content. At maturity, the effect of Si application rate and time on wheat grain yield, test weight, protein, and Si content were evaluated.