Grain Sorghum Response to Row Spacing, Plant Density, and Planter Skips

Adverse weather and soil conditions may prevent grain sorghum (Sorghum bicolor L. Moench) growers from achieving an evenly spaced, optimum plant density. In these situations, growers must decide whether to replant or manage a grain sorghum crop with uneven and/or lower stands. Research indicated that grain sorghum grain yield response to row spacing was variable and dependent upon environment. In uniform stands, grain sorghum was able to partially compensate for densities below 60,000 plants per acre by producing additional grain heads per plant. Results also indicated that in uniform grain sorghum stands, N at 100 to 150 lb/acre produced the highest grain yield under both high and low plant density conditions. In non-uniform stands with frequent 6- to 9-ft skips, sorghum had significantly reduced grain yield when compared to a uniform stand or 3-ft skips. These results do not support reduced N rates in either uniform or uneven grain sorghum stands with less than optimal plant densities.