AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Winter 1996, No. 7
DON'T NEGLECT CHLORIDE IN NUTRIENT MANAGEMENT OF WHEAT
Neglecting any of the controllable factors of production can be costly, especially when crop prices are good. Chloride is a plant nutrient that is frequently found in insufficient levels in wheat producing areas of the Great Plains and is often neglected in nutrient management. In most of the Great Plains, nitrogen and phosphorus are the only nutrients that are more likely to be insufficient.
Several symptoms of insufficient chloride in small grains have been identified by research conducted over the last 10 years. They include:
Chloride fertilization increases grain yield and grain quality. Besides increased tissue chloride, increased kernel weight and test weight are the most frequently observed effects of chloride fertilization. Test weight increases of 2 to 4 pounds per bushel are not uncommon. A recent research summary of over 200 evaluations of wheat and barley fertilization with chloride showed response 48 percent of the time and an average response of 5.2 bushels per acre. Wheat responses have been as high as 18 to 20 bushels per acre for individual varieties and sites. These were exceptional cases, but they illustrate the response potential for this nutrient that just a few years ago was ignored completely in crop management.
- Increased incidence of foliar diseases such as rust, septoria and tanspot
- Slower than normal reproductive crop development
- Premature death of the leaves
- Non-disease leaf spotting on some varieties
- Increased late-season lodging
- Reduced kernel weight and test weight
Chloride fertilization should be considered in nutrient management plans for wheat. Muriate of potash (0-0-60 or 0-0-62) is potassium chloride and is the most common fertilizer source of chloride. Potash contains 47 percent chloride. Thus, an application of 100 pounds of material gives 47 pounds of chloride. Magnesium chloride is a liquid source containing 22.5 percent chloride that is compatible with nitrogen solutions. Considerable placement flexibility exists, with broadcast, band, and early topdressing giving equal response in most cases. However, excess water will move chloride from the root zone, making time of application more important under conditions of high leaching potential. Recommended rates vary by state and province but are generally designed to bring the sum of soil chloride and applied chloride to a total of 30 to 60 pounds per acre.
"Leave nothing to chance" is a production philosophy shared by many successful producers. Neglecting chloride in nutrient management of wheat leaves the supply of this important nutrient to chance. The result may be reduced yield, lower grain quality and decreased profitability.
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