Agronomically and environmentally speaking, spring applications are frequently superior
to fall application because less loss of N occurs in the time between application and N uptake by
the crop. However, many U.S. corn growers, especially in the northern part of the Corn Belt,
desire to apply N in the fall because they usually have more time and field conditions are more
suitable for application. Early planting of corn as soon as the soils are fit in the spring is
desirable for highest yields and profit. Consequently, the window of opportunity for spring N
application becomes very narrow (Randall and Schmitt, 1998). Soil compaction and extended
periods of rainy weather can also be deterrents to spring application of N.