Updates are important and the University of Nebraska-Lincoln (UNL) sulfur recommendations will be modernized through a coordinated, statewide evaluation of corn–soybean systems. Results will identify conditions where sulfur improves yield, profitability and NUE across irrigated and rainfed systems. Recommendations are framed using probability of response and economic thresholds. Current guidelines are based on research from up to 25 years ago and no longer reflect modern challenges, such as declining atmospheric sulfate deposition and the increased nutrient removal of today’s high-yielding hybrids. Researchers will evaluate various application rates and sources—including ammonium thiosulfate (ATS), ammonium sulfate (AMS) and elemental sulfur—to determine the most effective treatments. Updated guidance will help producers avoid unnecessary fertilizer costs in irrigated systems while preventing under-application in highly vulnerable rainfed fields.