Micronutrient Spotlight – Chlorine (Part 3 in series)

Aug 3, 2022 | Latest news

Micronutrients can maximize crop performance

Andrea Rice, Director of Research, Education, and Outreach, Missouri Fertilizer Control Board

Chloride is one of the 17 essential nutrients and is often overlooked by growers.  Sampling for chloride before the growing season is the most accurate time for determining if a soil is chloride deficient.  Samples should be pulled from 24 inches or the depth plant roots can reach in that soil as chloride is highly mobile.

Soil chloride is often below critical levels in soils that carry acceptable levels of potassium.  This is due to minimal to low application of KCl or muriate of potash when KCl is a very cost-effective way to increase chloride levels in the soil.

How is chloride used by the plant?
Chloride assists the plant with the uptake of other soil nutrients and regulates the water flow through a plant.  The primary role of chloride is with crop growth and photosynthesis.  Chloride is important for stock strength and low levels may diminish crop yields by as much as 15 percent.

Plants can have greater resistance to diseases, specifically foliar diseases caused by fungi in winter wheat, corn, grain sorghum, and other crops when chloride levels are sufficient.

How should chloride be applied?
One of the most cost-effective ways to apply chloride is KCl, which is typically considered a potassium fertilizer but is also a great source of chloride.  Application of chloride can be at any point in the growing season with applications in winter and spring being equally effective.

Is there any information on chloride specific to Missouri soils?
The Corn Belt and Great Plains have very minimal chloride deposition due to their distance from any oceans.  There is also enough rainfall in these areas for chloride, which is highly mobile, to leach through the soil.

Is chloride more useful in specific areas of crop production?
Chloride deficiency can be more critical in wheat and other cereal grains.  To optimize yields in areas where KCl fertilizer has not been applied consistently, soil samples can be pulled to test for chloride levels before every growing season of crops such as sorghum, corn, and winter wheat.