On-Farm Corn Variety Trial Proves to be a Valuable Tool

July 11, 2022

Hannah Mikell, Clarendon County Agronomy Agent

Clarendon County Extension provides research to determine optimal corn variety selection for local climate and soils. This historical knowledge base improves understanding of local issues emerging in corn.

Clarendon County had a 2019 Corn value of $1,891,985. Each year corn acreage fluctuates between 10,000 to 20,000 acres. The corn industry in South Carolina has changed drastically in the last ten years. Commodity prices have decreased, and growers have moved from planting predominately a few varieties to using several each year in their farm portfolio.

Seed companies release new varieties yearly to compete for the South Carolina market. Knowledge concerning technology packages, disease resistance, yield potential, and uniformity are critical for Clarendon County grower success. The Clarendon Extension Agent addressed the issue by providing local on-farm corn variety trials each year for the past three years. The on-farm variety trial is a program for uniform evaluation of corn variety performance in on-farm situations at the county level. This program expands the number of environments in the assessment by encompassing approximately five or more locations across the state each year.

Yield data is compiled and shared at grower meetings at the end of the season. These research plots offer the opportunity for the county agent and grower to see how different varieties respond to the challenges of each growing season. Yield data from the research trial is the primary goal, but it also gives us a baseline across varieties for troubleshooting yearly environmental issues.

Immature corn ear with silk attached

Farmer surveying corn variety

Cross section of an ear of corn










As a result of planting the on-farm corn variety trial each year, the corn producers of the county have learned essential management practices. Local data on new varieties enables producers to make an educated decision on which varieties to choose. The yield difference in the trial’s top and bottom yielding varieties for the past three years averaged 94 bushels per acre. Growers who selected top-performing varieties could harvest upwards of 260 bushels per acre on farms planted to those varieties.

The closest research station to Clarendon County is in Florence and the growing conditions each year are much different than in Clarendon. For this reason, the local county research trials have benefited corn producers in Clarendon County. Corn growers in the county can look at multiple years of local county data to make better decisions on varieties in which they may have limited knowledge.

The unique challenges of each year showcase how the new varieties handle those stressors. Growers see the yield potential disease issues, heat sensitivity during the dry years, and stalk strength during challenging growing situations such as hurricanes. Having the corn variety trial for reference each year is invaluable to county agents and producers alike.

Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, gender, religion, national origin, disability, political beliefs, sexual orientation, gender identity, marital or family status and is an equal opportunity employer.