Chloride and sulfur could be two key nutrients to apply during the spring green up phase of winter wheat in southeast Nebraska. If these nutrients were not included in your fall fertilizer, an early spring fertilizer pass across the field may still be warranted. In southeast Nebraska, local observations and preliminary data suggest that sulfur and chloride applications may be needed for rainfed no-till winter wheat after soybeans.
Adequate availability of chloride for wheat has shown to suppress fungal diseases like tan spot, leaf rust, and stripe rust. Through a 2012 meta-analysis of Kansas chloride fertilizer studies, researchers observed an average yield increase of 8% due to chloride fertilizer application. K-State Extension specialists stated the probability of a yield response to chloride in rainfed wheat in north central and northeast Kansas seems higher than in western Kansas. K-State has soil sample interpretations for chloride concentration in the 0 to 24-inch depth and corresponding fertilizer recommendations. Results from two 24-inch soil samples that I took from two rainfed wheat fields last fall were 0.7 and 2.6 parts per million (ppm), both low (<4 ppm) by K-State Extension interpretations. Flag leaf nutrient analysis could help determine the current and future need for chloride fertilization in southeast Nebraska. Chloride concentrations less than 0.18% in the flag leaf at the start of heading can indicate chloride is not sufficient according to K-State. As a result of this information, I conducted a wheat flag leaf nutrient analysis survey in May of 2021 across 30 winter wheat fields in Saline, Jefferson, and Gage counties. Ten of the 30 wheat flag leaf samples or 33% of the fields were low in chloride. An application rate of 20 pounds of chloride per acre or about 50 pounds of potash fertilizer per acre is sufficient to prevent deficiency. Potash fertilizer has a 45-47% chloride content and is a readily available option to use as wheat begins to green up.
Sulfur deficiency has been documented in areas of southeast Nebraska dating back to 2011. Visible symptoms of sulfur deficiency have been more common in fields with eroded hillsides where there is low organic matter silt loam and silty clay loam soil. Likewise, no-till winter wheat fields in north central and northeast Kansas have a longer documented history of visible sulfur deficiency compared to other regions in Kansas according to K-State Extension specialist. Sulfur deficiency is noticed in early spring after green up and can be confused with a shortage of nitrogen. In addition to potential yield benefits of sulfur, end-use quality is improved when wheat has sufficient sulfur. New research from K-State found sulfur application reduced asparagine concentration in the grain, which lowers the potential for acrylamide (probable carcinogen) formation during food processing. Application rates of 15 to 20 pounds of sulfur per acre or about 75 pounds of ammonium sulfate per acre is sufficient to prevent deficiency. Dry fertilizer grade ammonium sulfate has a 24% sulfur content and is a readily available option to use as wheat begins to green up.
I encourage farmers to conduct their own research to fine-tune these initial recommendations and to get assistance through our Nebraska On-Farm Research Network. For more information, feel free to contact me at or 402-821-1722. Know your crop, know your tech, know your bottom line at croptechcafe.org.
