Impact of split application of potassium fertilizer on yield, quality, and economic benefits of winter wheat

Background Potassium (K) is essential for winter wheat growth, yield formation, and grain quality; however, it is commonly applied as a single basal dose in the Huang-Huai-Hai region despite large spatial variability in soil K availability, leading to inefficient utilization. Aims This study aimed to evaluate K application strategies across contrasting regions and identify an optimal, site-specific K management approach. Methods Field experiments were conducted during 2021–2022 and 2022–2023 at three sites with contrasting soil K levels. A two-factor randomized block design with three replicates was used, including two K rates (K1: 120 and K2: 60kg K 2 O ha -1 ) and five application methods: no K (T1), single basal (T2), two-split (T3: 50% basal + 50% jointing), three-split (T4: 20% basal + 30% jointing + 50% anthesis), and single controlled-release basal (T5). The strong-gluten winter wheat cultivar ‘Weilong 169’ was used. Results Basal and controlled-release treatments (T2 and T5) increased the available K in the 0–60-cm soil layer during early growth, while split application (T3 and T4) improved the K availability in the surface layer (0–30 cm) during later stages. The three-split application (T4) consistently improved K accumulation, 1, 000-grain weight, and grain yield across all sites. In high-K soils, single basal application showed no significant yield advantage, underscoring the importance of application timing. Split K application, particularly T4, also improved the grain quality traits, including protein content, wet gluten content, sedimentation value, and dough rheological properties. These improvements were associated with enhanced post-anthesis K uptake and KUE. Conclusion Optimizing K application timing through split fertilization improves K utilization, yield, and grain quality. A site-specific strategy is recommended: 120kg K 2 O ha -1 applied in a 2:3:5 ratio (sowing/jointing/anthesis) for K-deficient eastern regions and K 2 O ha -1 with the same split ratio for high-K western regions. This approach provides a sustainable and efficient fertilization strategy for winter wheat production in the Huang-Huai-Hai region.