Molecular Soil Biology 2025, Vol.16, No.6, 314-324 http://bioscipublisher.com/index.php/msb 315 2022). Nitrogen and phosphorus are mainly concentrated in the grains, while the content of potassium in straw is usually higher than that in the grains. There is a clear physiological interaction between the form of nitrogen and the supply of potassium. When the potassium supply level is relatively high, it can reduce the toxic effect of NH4⁺ on plants and simultaneously improve the utilization efficiency of NO3 - (Cao et al., 2025). 2.2 Minor and micronutrients (S, Zn, Fe, Mn, Cu, B) Sulfur is a component of sulfur-containing amino acids and various coenzymes, and is closely related to protein content and baking quality. Under an optimal nitrogen and water content of 120 kg N + 30 kg S·ha-1, N and S absorption, as well as NUE and SUE, reach their highest levels throughout the plant's growth period (Sai et al., 2025). Zinc participates in membrane stability, hormone metabolism, and phytochrome activity; iron and manganese are key components of the photosynthetic electron transport chain and various redox enzymes, while copper plays a role in photosynthesis and respiration, lignin synthesis, and pollen viability. Boron has specific functions in cell wall formation, pollen tube elongation, and grain development; deficiency leads to inhibited heading and grain setting. S, Zn, and B are generally deficient in many regions, and multiple micronutrient deficiencies are common, representing latent factors limiting wheat yield and nutritional quality (Shukla et al., 2021). Approximately 3 billion people worldwide are affected by Zn and Fe deficiencies, and wheat grains naturally have low levels of Zn and Fe. In some major producing areas, the average Zn and Fe content measured is significantly lower than the recommended values for human health (Wysocka et al., 2025). In low-fertility or calcareous soils, soil or foliar application of Zn, Fe, Mn, Cu, and B can improve plant absorption and grain enrichment. Foliar spraying of a micronutrient mixture can increase the Zn, Cu, Fe, Mn, and B content in grains by 21%~47% (Raza et al., 2025). 2.3 Nutrient requirement rhythms during wheat growth stages Wheat seedlings to tillering stages are particularly sensitive to phosphorus and some nitrogen. Sufficient P and adequate N promote root development, tillering, and canopy formation. After entering the jointing-heading stage, the accumulation of dry matter and the absorption rate of N and K in the aboveground parts accelerate significantly, forming the absorption peak of the entire growth period (Kumar et al., 2023). From heading to flowering to grain filling, the net absorption of exogenous nutrients by the plant gradually weakens, and the N, S, Zn, Fe, Mn, and Cu in the grains mainly rely on the retransportation of nutrients stored in vegetative organs (leaves, stems, and glumes). The absorption peaks of macronutrients and micronutrients also show stage differences. During the grain filling stage, wheat absorbs Zn and Mn most vigorously, while Cu absorption is more sensitive around the jointing stage. 3 Key Components of Integrated Nutrient Management in Wheat 3.1 Chemical fertilizers Under alkaline soil and saline-alkali land conditions, appropriately increasing the application of nitrogen and phosphorus fertilizers can significantly promote the growth of wheat. The application of 180 kg N·ha-1 in combination with 80 kg P·ha-1 has a better effect in terms of yield increase and nutrient absorption (Hou et al., 2025). In calcareous soil, nitrogen sources mainly composed of nitrate nitrogen are more conducive to nutrient absorption by crops than ammonium nitrogen. The use of nitrate nitrogen can improve the utilization rate of N, P and K by wheat (Alvi et al., 2025). In dryland areas, soil fertility is often limited. This problem is more serious in fields with long-term continuous cropping. In these fields, applying NPK fertilizer at the recommended rate is necessary. At the same time, adding organic fertilizer brings clear benefits. This practice helps crops grow better and also improves the soil. Soil organic carbon increases. Available nitrogen, phosphorus, and potassium also rise. Some trace elements, such as zinc and iron, become more available as well (Walia et al., 2024). Among different treatments, replacing 50% of chemical NPK with farmyard manure gives the best result. Nitrogen management is also important for winter wheat. Applying all nitrogen at one time is not a good choice. Splitting nitrogen into several applications works better in most cases. Base fertilizer is applied first. Top dressing is then added later. This approach helps wheat get enough nitrogen at key stages, especially during jointing and booting (Fasani et al., 2025). In rotation systems
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