Sulfur fertilization optimizes maize yield through nutrient regulation and biomass responses in six contrasting soils of Northeast China

Introduction Sulfur (S) deficiency has re-emerged as a constraint to maize production due to reduced atmospheric deposition and the widespread use of S-free fertilizers. However, how S fertilization influences yield formation under contrasting soil conditions in Northeast China remains insufficiently quantified. Methods Here, a two-year field experiment was conducted on six representative soil types using five S rates (0, 30, 60, 90, and 120 kg S ha - ¹) with measurements of grain yield and its components, S and N accumulation and stoichiometry, and dry matter production and remobilization before and after silking. Results Across the six soils, fitted optimal S rates (61.4–89.7 kg S ha - ¹) increased grain yield by 2.5%-25.8%, with the largest responses observed in black soil and aeolian sandy soil. Yield gains were mainly associated with increases in kernel number and thousand-kernel weight, supported by path analysis. Moderate S supply (S60–S90) enhanced S and N uptake at silking and maturity, improved N/S ratios, and increased pre-silking biomass accumulation. Biomass remobilization efficiency increased from 5.0% (S0) to 11.6%–11.7% (S60–S90), contributing to a higher harvest index (40.8% at S0 vs. 42.6%–42.7% at S30–S90). Pre-silking biomass was positively related to grain yield across soils. Discussion Overall, under the studied conditions, S fertilization improved maize yield primarily through promoting early-season growth, nutrient coordination, and biomass remobilization rather than increasing post-silking assimilation alone. These findings provide a scientific basis for soil-specific sulfur management in temperate spring maize systems of Northeast China.