Response from Brad Farrell in Fertilizer, Soil, Nutrients | AGvisorPRO

Advantages to fall-applied: usually cheaper per pound of N; usually have a wider application window compared to spring; usually less compaction risk compared to spring Disadvantages to fall-applied: increased risks of nitrogen loss; decreased flexibility for crop rotation (i.e. you wouldn't want to plant soybeans or alfalfa in the spring if you had already applied N in the previous fall);