Ammonium sulfate fertilizer (containing 20% nitrogen and 24% sulfate) is one of the nitrogen-containing fertilizers that can be used as a top dressing for wheat, especially in cold areas during the spring. This fertilizer can also help meet the plant's sulfur requirements as it has sulfate nature.
In order to increase the quality of wheat grains, especially to increase its protein content, managing nitrogen application is of particular importance. The uptake of nitrogen by wheat in the late stages can lead to an increase in the protein content of wheat grains. The soil application of nitrogen fertilizers in the late stages of wheat growth is associated with challenges; however, the best method for applying nitrogen fertilizers at this time is through foliar spraying. Therefore, it is recommended to foliar spray ammonium sulfate or urea at a rate of 4 to 8 kilograms per hectare during the 7 days after 50% wheat heading. The foliar application of nitrogen fertilizers at this stage can be done simultaneously with the use of herbicides to combat wheat rust.