Chloride in Kansas: Plant, Soil, and Fertilizer Considerations
Cristie Preston, Ph.D.
Agriculture has always been an integral part of Dr. Cristie Preston’s life. She grew up in southwest Virginia and had interest in crop and animal agriculture since an early age. Once she began college, she initially chose to study animal science but switched to soil science. Dr. Preston attributes her decision partly to an influential professor who told her, “You can’t understand animals until you understand what they eat.” She received a Bachelor of Science degree in animal science and a Master of Science degree in crop and soil environmental science from Virginia Tech. Dr. Preston holds a Ph.D. in agronomy, focusing on soil fertility from Kansas State University. While completing her advanced degrees, Dr. Preston conducted more than six years of field and lab research. Dr. Preston has experience in laboratory research measuring volatility loss from urea-based fertilizers. Her field research has focused on phosphorus availability and the interactions with tillage and placement. She also has extensive experience in working with large data sets and analysis. Her main priority is helping growers to identify yield-limiting factors and fix those issues as cost efficiently as possible.
The main function of chloride (an anion — negatively charged particle) in plants is as a counterion for cations (positively charged particles such as calcium, potassium, magnesium, and ammonium). The plant must maintain a neutral charge balance, and chloride helps to achieve that.
Chloride application has been shown to reduce the effects of numerous diseases on a variety of crops. Specifically, in winter wheat, chloride suppress diseases such as take-all root rot, common root rot, tan spot, powdery mildew and leaf rust.
Since chloride is an anion, it is not readily adsorbed on the soil exchange complex and is, therefore, subject to leaching. Kansas State University recommends sampling to a depth of 24 inches (like nitrogen and sulfur) to best assess soil chloride levels. Of the crops grown in Kansas, grain sorghum, wheat, and corn are the most likely to respond to chloride applications.
If you apply potash (KCl) as your source of potassium, then you are probably applying enough chloride to not see any issues. However, if you are utilizing other sources of potassium, then chloride might be limiting crop productivity.