Soil Science Dept.
Excessive nitrogen can contribute to decreased oil content in the seed.
Total plant nutrient requirement for a crop depends on the total production of that crop. Establish realistic yield goals. When estimating yield goals, consider the highest yield that has been produced on a particular field and then make adjustments from that point. Usually the yield goal should be within 200 pounds of the highest yield of sunflower ever produced on the field in question. Excessive fertilizer use, especially nitrogen and phosphorus, has potential to degrade ground and surface water quality.