Rates need to be high enough to maximize plant growth and also ensure good protein assimilation in both grain and silage crops.
However, too much nitrogen can encourage excessive leaf growth, increasing the proportion of leaf and stem to grain. As a result, the starch content of corn silage can be reduced and corn yields can also suffer.
Uptake of phosphorus from the soil continues after the grains begin to develop and, at maturity, 70% of the phosphorus in the plant is in the grain. Here it has a direct effect on grain corn protein. At later stages of growth, phosphorus boosts the development of grain and accelerates crop maturity.
Potassium nutrition increases crude protein content of forage corn. There is evidence that boron increases the starch content of forage corn, increasing forage corn energy.
There is evidence that boron increases the yield and starch content of forage corn. Foliar applications made at the V5 or V6 stage, when there is significant leaf cover, will improve yields in deficient crops.
Zinc is an essential component of enzymes involved in carbohydrate metabolism and protein production. Therefore, a low zinc supply reduces growth and starch content of corn.