Critical concentration of available soil phosphorus for grain yield and zinc nutrition of winter wheat in a zinc-deficient calcareous soil

Background and aims The decrease in cereal grain zinc (Zn) caused by phosphorus (P) application has attracted wide attention. However, optimizing P fertilization for both satisfactory grain yield and grain Zn concentration is still a problem due to a poor understanding of the relationship between P application rates and available soil P, and that of available soil P and soil Zn availability, relevant soil factors, and plant Zn uptake and utilization.