Do Hard Red Spring Wheat Varieties Vary in Their Response to Sulfur?

Abstract

Sulfur is increasingly reported as deficient in many crops in the Upper Midwest of the United States. The objectives of this study were to determine if hard red spring wheat (HRSW) (Triticum aestivum L. em thell.) varieties vary in response to S and to determine if plant tissue analysis can predict grain yield. Two studies were established in Minnesota. Study 1 compared two sources of S applied at four rates with and without in‐season S. Study 2 compared the response of six HRSW varieties to three rates of S (0, 8, and 16 kg S ha−1). Spring wheat grain yield and protein concentration were not affected by S rate, source, or timing with soil organic matter (SOM) >20 g kg−1. For locations with SOM <20 g kg−1, which were all sandy and irrigated, 8 kg S ha−1 maximized grain yield and protein concentration. Flag leaf S concentration varied among varieties separately from S rate applied. Wheat grain yield decreased when flag leaf S concentration was <4.1 g S kg−1, and grain yield responses were likely with concentrations <2.8 g S kg−1. There were negative relationships between tissue N/S concentration ratios and grain yield, but critical N/S concentration could not be determined. Application of S for HRSW should be targeted to soils with SOM <20 g kg−1 (0–15 cm). Sulfur rates sufficient to increase yield will result in an optimal protein concentration, and guidelines should not be varied based on the variety grown.Core Ideas Application of 8 kg S ha−1 increases hard red spring wheat yield on sandy soils. Flag leaf tissue S concentration will vary based on hard red spring wheat varieties. Variety variation in flag leaf total S concentration cannot predict variety sulfur requirements. Sulfur application rates should not be changed based on hard red spring wheat variety. Tissue total S concentration is a better predictor of grain yield than the N/S concentration ratio.