Objectives The study aimed to clarify the relationship between wheat yield and protein formation and sulfur requirement, and assesses the deficiency status and the urgency of sulfur fertilization in major wheat production regions of China.

Methods During the three consecutive wheat growing seasons from 2021 to 2024, 635 wheat plants and soil samples were collected from farmers’ fields in 18 major wheat production provinces (municipalities or districts) in China to analyze wheat yield, grain S and protein concentration, then the S requirement and soil available S content (AS) across different wheat production regions were assessed based on the analysis data.

Results Wheat yield did not show significant correlation with grain sulfur concentration in the four wheat production regions, positive correlations were found between grain S and protein concentration in all production regions (P<0.01). For each 1.0 g/kg increase of grain S concentration, the protein concentration increased by 6.50%, 6.27%, 3.92%, and 5.15% respectively in the four wheat production regions, averaging 5.30% across China. The wheat S requirement ranged from 1.61 to 6.62 kg/Mg, with average of 3.14, 3.21, 3.32, and 3.02 kg/Mg in the four wheat production regions respectively, and a national average of 3.21 kg/Mg. The S requirement in spring wheat and rice−wheat production regions showed positive correlations with grain S concentration but negative correlations with wheat yield, while in dryland wheat and wheat−maize production regions, it demonstrated positive correlations with both grain S concentration and yield (P<0.01). The soil AS content in wheat field varied greatly, ranging from 1.8 to 716.7 mg/kg. Regional averages were 33.1, 30.2, 37.5, and 33.2 mg/kg respectively in the spring wheat, dryland wheat, wheat−maize and rice−wheat production regions, and the national average was 36.2 mg/kg. There are 62.4% of wheat fields were low or very low in AS contents, and sulfur−deficient wheat fields were found in all 18 major wheat production provinces or municipalities. As soil AS content increased, shoot S accumulation of wheat increased, while the grain S distribution index exhibited a downward trend, the ability of S transportation and transfer from shoot to grain decreased, and wheat S requirement increased.

Conclusions There is a high proportion of sulfur−deficient fields in major wheat production regions of China, hence the soil AS content still needs to be improved. Wheat S requirements varied with yield and grain S concentration of different wheat production regions. Improving S supply capacity of soil can enhance the S absorption of wheat, but it reduces S translocation to grain.It is necessary to comprehensively consider the soil AS levels and wheat S requirement of the yield and quality formation to determine the S fertilization coefficient, to achieve wheat yield and quality improvement.