Effect of Silicon Fertilization on Growth, Yield, and Disease Development in Wheat Plant.

Silicon (Si) is known to enhance crop’s ability to withstand biotic and abiotic stress therefore can help crop maintain productivity even in adverse environmental conditions. In Louisiana, wheat production is commonly challenged by high disease pressure. A field study was conducted at two locations in Louisiana in 2014 to evaluate the effect of Si fertilization on wheat productivity using yield, nutrient uptake, grain protein content, and disease severity as metrics. Treatments included two nitrogen (N) fertilizer rates (100 and 145 kg N ha^-1) and for each N rate, the following treatments were included: three rates of Si solution (120, 240, and 480 mg Si L^-1) as foliar spray, two Si granular sources (wollastonite – 23% Si and slag – 12% Si) applied at 250 kg Si ha^-1, a foliar spray with carrier solution, and a check plot. All treatments were replicated four times and arranged in a randomized complete block design. Rust infection rate taken at heading stage in one location was generally reduced by 25% with the application of either foliar Si and granular Si; the positive effect was more pronounced in plots applied with 145 kg N ha^-1 where as much as 50% reduction in leaf area affected by rust was recorded. Significant increase in soil Si was observed with wollastonite and slag-treated plots accompanied with significant increases in Si content and uptake by wheat biomass for both locations (P<0.05). While soil Si from foliar Si-treated plots remained comparable with the control, significant increase in Si content and uptake of biomass at flowering was observed. However, these increases in Si uptake did not translate to significant increase in grain yield. Collectively, the available data demonstrated that both soil and foliar Si application enhanced Si uptake by wheat but the positive effect on productivity and disease development needs further investigation.