The objective of this research was to study the effects of phosphorous and foliar iron fertilizations rates on the of protein, fiber, and water contents in wheat grains. Treatments of fertilizers included a combination of three foliar iron rates (0, 1.2, and 2 L/ha, Fusion) and four phosphorus rates (0, 75, 150, and 225 kg/ha, P2O5) at three replications. The quality parameters of harvested seeds were measured by the NIR technique. Protein content increased but and fiber and water contents decreased significantly with an increase in the iron and phosphorus fertility rates. As the rates of foliar iron increased from 0 to 2 L/ha the mean values of protein content increased significantly from 13.47% to 15.48%. With increasing the rates of phosphorus from 0 to150 kg/ha, the mean values of protein content increased significantly from 13.56% to 15.53%, however, further increase in phosphorus, causing a decreased trend in the amount of protein. Fiber and water contents of wheat decreased significantly from 13.76% to 11.86% and from 7.36% to 7.28%, respectively, as the phosphorous rate increased from 0 to 225 kg/ha. Those changes were from 13.40% to 12.03% and from 7.57% to 7.21%, respectively, for increasing foliar iron from 0, 1.2, and 2 L/ha. Mathematical relationships composed of phosphorus and iron fertilizers were developed for accurately describing the wheat protein, fiber, and water contents under different fertilization rates.
Keywords: iron fertilization; phosphorus; quality; wheat.