The grain mineral composition of barley, oat and wheat on soils with pH and soil phosphorus gradients

•pH has a stronger effect on grain nutrient composition than soil extractable cations.•Changing pH leads to different variations of grain nutrients among cereals species.•Cu, Fe, Se and Zn concentrations in grains are weakly related to soil pH.•Grain composition cannot be used to indicate the bioavailability of nutrients in soil.