Hog manure can be an important supplier of N to soils but mismanagement of the manure application can lead to air and water pollution. Manure loss is known to happen but a more in-depth look at where losses are occurring can help minimize them. In this study liquid manure was used mixed with ¹⁵N to track N transformations and to directly measure manure N recovery in crops, retained in soil, and total losses by leaching and gaseous emissions. The experiment took place at two sights each of which had different soil characteristics and draining systems (one was sloped, the other not). The manure was enriched with ¹⁵N by feeding it to the pigs. Manure was spread in three different time periods: late fall, spring, and side dress in June. Several rates of inorganic N were applied along with one control with no manure or fertilizer. All the plots were planted with corn, and regular soil and water sampling from drainage was carried out. Also samples of the corn were taken. For the manure applied in late fall there was 29% loss of manure N recorded over the winter at one sight. Sights which had manure applied (all but the control) produced water samples that tested positive for Nitrate N, suggesting that manure N was leaching into the drainage water. The amount of N absorbed by corn was 15% for the plot spread in late fall, for the side dressed and spring application the corn absorption rate was 30-35%. This difference can be explained by the difference in N loss, late fall having a loss of 35-40% compared to that from spring, 15 – 22% loss, and side dress applications 7 – 9% loss. Clearly, spring application, particularly as side-dress has an advantage in terms of reducing environmental losses. The actual impact of environmental losses is dependent on the form of N lost, as gases or in leaching.