Making grain sorghum great again: A two-year case study in southern Illinois
Grain sorghum, Sorghum bicolor (L.) Moench, in Illinois, known hereafter as sorghum, was an important rotational crop that could handle the unique stresses of the southern third of the state. The success of sorghum was attributed, in part, to the marginal crop production land of the region, the appropriate growing season, and the proximity to river terminals for easy grain marketing. However, the development of herbicide tolerant crop cultivars, advances in crop breeding, and consolidation of farms and grain terminals have reduced sorghum acres to pre-1970s level. This case study identified the economic opportunity, addresses agronomic practices, and suggests farmers may benefit from including sorghum into production plans. The study included a variety trial consisting of seventeen hybrids tested at three densities in a complete block design with no replications in 2018. Wet weather caused a modification to the 2019 design and only six entries at three densities in a replicated complete block design were evaluated. Three densities represented the low, middle, and high of the regional spectrum; 40,000, 80,000, and 120,000 plants per acre. Soybean Glycine max (L.) Merr plots were planted adjacent to the sorghum plots and used as an economic comparison. Plot size was 250 feet long by 22.5 feet wide. Field selection was made to compare two drastically different environments in Jefferson County, Illinois. Commercial equipment was used to plant and harvest the study.
An economic evaluation revealed two categories to rank conclusions; a yield optimum (YO) and an economic optimum (EO) where the YO seeks to maximize yield while the EO factors input costs and seeks to optimize profit. In 2018 the EO of 80,000 plants per acre netted significantly more dollars per acre compared to growing soybeans. The YO was 120,000 plants per acre. In 2019 the trial was heavily impacted by weather resulting in mostly negative outcomes, with notable exceptions, when compared to producing soybeans. Simply, in 2019 the soybean comparisons had the best economic return while the opposite was true in 2018. In both years planting 80,000 plants per acre proved to be the EO density while it was not economically or agronomically beneficial to plant 40,000 and 120,000 plants per acre.