Southern Spotlight: The Value of Chloride in Winter Wheat

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Amanda Fairley

As the season of fall deepens, some of you may be considering fertilizing your wheat crop already.  Nitrogen, phosphorous, and potash have most likely been applied as a starter fertilizer, in addition to zinc and sulfur.  Odds are however that when you determined your starter fertilizer blend, chloride may not have been on your radar. But don’t fear, as this micronutrient with significant benefits can be added to your your topdress blend.

Although research dating back to the mid-1950s has proven the value of Chloride to crops, and though chloride can be utilized by plants in amounts similar to sulfur, it’s still a relatively new player on the agronomic scene.  However, its value is becoming increasingly apparent.

Chloride has multiple benefits for our growing wheat: it aids in mitigating stress, suppressing root and leaf diseases, increasing water use efficiency, facilitating nutrient transportation, and promoting photosynthesis and enzyme activity.  This total package of benefits results in the accelerated development of our wheat plants.

In recent years, North Central Kansas has been depleted of moisture, whether from rain or snow.  Field trials have demonstrated that Chloride increases yields in drought conditions by facilitating efficient stomatal activity.  Stomata are the tiny pores on the surface of a leaf that allow the intake of carbon dioxide and the evaporation of water.  Stomata in good working order allow minimum evaporation, retaining that precious water for use by the plant. Field trials further demonstrate a 7 bushel/acre increase on chloride treated acres in low moisture situations.

North Central Kansas also faces the challenge of leaf diseases.  In 2011, everything from Striped Rust to Tan Spot to Powdery Mildew could be readily found in our wheat fields.  Chloride aids in suppressing such diseases as it improves nitrogen uptake.  Higher levels of chloride stimulate the uptake of ammonium nitrate, which is a key nutrient in disease suppression.

Wheat

There are four readily available sources of chloride for your use.  Calcium chloride and Magnesium chloride are options, but have proven troublesome if applied with phosphorous.  Potassium chloride has proven worth as a source, though a fourth source, Ammonium chloride, is the most versatile as it provides nitrogen and mixes well with other solutions of nitrogen and sulfur.

It is recommended that you sample your soil for Chloride levels prior to planting each year. If by chance you didn’t test for Chloride with your early soil sample, you can still sample now and any Chloride deficiency can be addressed with a spring topdress.  In fact, a spring application of Chloride provides the maximum benefit to your crops.  Check out the photo below.  As you can see, any application of Chloride, whether in the fall or spring, results in greater plant health and head size, but the spring application produces the most dramatic results.

Your crops’ response to Chloride will vary depending on level already present in your soil, the disease pressure in your fields, and the variety you have chosen to plant.  Overall though, chloride is a nutrient that will help you attain the best wheat crop possible by promoting larger head and kernel sizes and supporting season-long plant health, standability, higher test weights, and increased yields.