Chloride Fertilizers Increase Spring Wheat Yields in the Northern Great Plains

Not only is potash a great source of potassium, it can also be utilized as a source of chloride. Some states in the Great Plains and Midwest need additions of chloride for crop production. Universities in the Great Plains are working on fertilizer recommendations and critical values for chloride in spring and winter wheat.

Research has shown that chloride additions can positively affect wheat yield by as much as 4 bushels per acre and suppress diseases such as take-all root rot, common root rot, tan spot, powdery mildew and leaf rust.

This recently published article by Graham et al., 2017 in the peer-reviewed Agronomy Journal quantified spring wheat yield response to chloride fertilizer in the Northern Great Plains. Based near Aurora, South Dakota, the research site consisted of chloride studies from 1997-2000 and then again in 2002. Both Muriate of Potash (MOP, KCl) and calcium chloride (CaCl2) were used as chloride sources.

Researchers found:

• There were no significant differences between potassium sources.
• “Across all site-years of the study, results show a statistically significant grain yield increase of 0.17 t/ha-1” (2.29 bushels per acre).
• “Where pre-plant soil test Cl- levels were lower than 1.87 mg/kg-1, fertilizer Cl- applications increased grain yield by 0.26 t/ha-1 with an average return of $18.42 ha-1.”
• That is equivalent to 1.87 ppm soil test chloride, 3.5 bushels per acre increase and $7.45 per acre.
• “The potential of profitability of Cl- fertilizer application is highly dependent on the choice of cultivar.”

This paper includes an excellent review of previous research in its introduction, discussing how chloride may protect the plant roots from pathogens such as those that cause common root rot in barley. Mechanisms have been suggested that chloride presence may cause plants to take up ammoniacal forms of nitrogen as opposed to nitrate, which would aid in making the plant less susceptible to pathogens. Other researchers have found a reduction of tan spot, powdery mildew, and leaf rust with the applications of chloride.

Conversion factors:

• 2,000 pounds in 1 ton
• 1 hectare is 2.47 acres
• 1 bushel wheat is 60 pounds