Fertilizer Nitrogen and Crop Rotation in Relation to Movement of Nitrate Nitrogen Through Soil Profiles

Recovery of fertilizer N by three successive corn ( Zea mays L.) crops and as inorganic N in the soil profile following the last crop ranged from 72 to 88%. Total amount of NO 3 ‐N in the soil profiles was directly related to the rate of N application and to the frequency of corn in the rotation. More leaching of NO 3 ‐N generally occurred between fall and spring samplings than during the growing season. The most effective methods indicated for limiting the amounts of NO 3 ‐N passing through the soil profile to the water table include: limiting rates of N fertilizer to approximately that required by the crop, reducing the acreage and frequency of corn or other crops that received fertilizer N in the rotation, and maintaining a crop cover on the land as much of the time as is feasible.