Fall application of fertilizer offers the advantages of (1) getting a job done which can delay early spring planting, (2) being able to get over fields when they are usually drier and less likely to compact, and (3) more often getting a price break from fertilizer dealers. Several crop-related advantages also apply and are discussed below. In terms of nutrients which can be fall applied, phosphate and potash are well adapted, Both these nutrients react strongly enough with soil to resist overwinter leaching. and the requirements for next year's production can safely be applied in the fall. Fall use of nitrogen is a different situation. Under Kentucky's soil and climatic conditions much of the nitrogen applied during the fall is likely to be lost during the winter because of leaching, denitrification, and immobilization. Even when used with nitrification inhibitors, fall application of nitrogen has not performed as well as spring applied nitrogen in Kentucky research.
Wells, Kenneth L., "Fall Application of Fertilizer" (1985). Soil Science News and Views. 149.