Lodging, harvest issues, and insect pressure are common concerns with grain sorghum [Sorghum bicolor (L.) Moench] production. Phosphorus (P) has historically been applied prior to planting and as seed company genetic yield potential has improved the impact to existing uptake curves, translocation timing of nutrients from stalks to grain, and the influence on stalk lodging is unknown due to a lack of updated research. Calcareous, high pH soils reduce the availability of P and potassium (K) leading to plant deficiencies. The interaction of nutrients and plants with silicon (Si) and the impact on yield is a frequent topic of recent research. The purpose of this study is to evaluate new fertilizer technologies that can be foliar applied and the benefit of late season application as a management tool to reduce lodging and increase harvestable yield.

A replicated strip trial was conducted with three fertilizer products in 2020 near Kress, Texas. Products utilized were Redox Ag Rx Platinum^TM 1-7-12, P-58 10-58-0, and Mainstay^TM Si 10 Ca-22 Si. Mainstay^TM Si was incorporated into the trial to evaluate plant-soil nutrient relationships and pest response. 2 replications of each treatment were applied at boot stage or 46 days after planting with 90.92 liters of water as carrier and applied with a self-propelled 36.58-meter boom ag sprayer. Boot stage was chosen because of significant yield reduction caused by stress at this stage.

Stalk diameter was 6% larger (P=0.05) in the P-58 treatment than Mainstay^TM Si and 4% larger than other treatments. Grain nitrogen (N) content was 8% higher (P=0.10) in the Rx Platinum^TM than the P-58 and 4% higher than other treatments. There was no treatment effect on plant health, disease and insect pressure, lodging, plant height, or yield between treatments.

Plant health, weather conditions, stalk diameter, and grain maturity are factors that contribute to lodging. Lodging did not occur in any of the treatments in this trial. Since P-58 increased stalk diameter, it stands to reason that sorghum lodging is minimized and yield increased. Timing of such treatments to achieve the greatest benefit should be evaluated further. The interaction of Si with other nutrients and plant processes resulting in improved plant health and stalk strength also requires further evaluation.