Sulfur and chloride could be two key nutrients to apply during the spring green up phase of winter wheat in Eastern Nebraska. If these nutrients were not included in your fall fertilizer, an early spring fertilizer pass in March across the field may still be warranted. In Eastern Nebraska, local observations and data suggest that sulfur and chloride applications may be needed for some rainfed no-till winter wheat fields.
Winter wheat sulfur deficiency (pictured in image above) is well-known in areas of Southeast Nebraska dating back over a decade. 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 greenup and can be confused with nitrogen deficiency. 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 or 100 pounds of pelleted gypsum (calcium sulfate) per acre is sufficient to prevent deficiency. Dry fertilizer grade ammonium sulfate or gypsum is a readily available option to use as wheat begins to green up. Do not use elemental sulfur as the conversion from sulfur to sulfate is too slow for winter wheat in the spring.
There is a lesser-known chloride nutrient deficiency in Eastern Nebraska winter wheat. Adequate availability of chloride for wheat has been 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. Flag leaf nutrient analysis could help determine the current and future need for chloride fertilization in Eastern 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 those research findings, I conducted wheat flag leaf nutrient analysis surveys in 2018, 2019, and 2020 in Eastern Nebraska across 56 winter wheat fields. Of these fields, 25% of the fields were low in chloride and could have benefited from chloride fertilizer applications. 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 greenup.
I encourage farmers and companies 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.
