Field Based Determination of Chloride Tolerance in Soybean Dr. Trent Roberts, University of Arkansas Associate Professor of Soil Fertility and Testing

Dr. Trent Roberts, associate professor of soil fertility and testing at the University of Arkansas, oversees the University’s chloride testing research project. The project aims to increase the resolution of the screening and diagnostic process to better assist producers with finding the best soybean variety for their field.

Water quality and the plant itself contribute to high chloride in soybeans.

Chloride in the water soaks into the soil because Arkansas soil drains poorly. Small concentrations build up quickly over 5-10 years. Therefore, water is the preferred testing method.

“If we measure the water source, that gives us a good idea at least of what we’re adding. Irrigation water quality is a good predictor of whether or not I’m going to have an issue in a particular field,” Roberts said.

The plant itself has a role to play, too. Chloride is an essential element for soybeans. However, high accumulation can lead to chloride toxicity. Soybean varieties are either includers or excluders. Includers have no filter or screening mechanism. They absorb chloride indiscriminately. Excluders, however, have a screening mechanism to help them filter out the chloride they absorb from their environment.

The first visible symptom of chloride toxicity is scorching on the very edge of the leaves on the plant. However, Roberts says once that happens, the damage has been done.

“Unfortunately, you’re losing yield before you ever see that symptom. If you get to the point where you see scorching in an includer or excluder variety, you’ve lost a significant amount of yield,” Roberts said.

Roberts created a new protocol for field-based testing, so producers can know what their options are. Using samples from ongoing variety trials, varieties are categorized by chloride sensitivity or tolerance. He hopes this will help producers as they decide what soybean varieties to plant or not plant.

Roberts also wants to see this project expand across the whole state to learn if there are areas affected by chloride toxicity that no one knows about.

Producers experiencing issues negatively impacting their yields can get help by contacting their local county extension agent. Find your local county extension office here to start that conversation today.

Watch the full Field to Film: Featured Research video series here to learn more about current checkoff-funded research projects. Find the podcast version of this series for on-the-go listening here.