Different factors have an effect on the possibility of impact on ground and surface water. Some of those factors are: the proximity of a water body, where in the landscape the manure is spread and the management of the application such as the rate, the technique used and the time of application. To minimize the potential impact of manure application on the environment, the method used to spread manure has to be appropriate and the application rate has to be known. In sensitive land areas next to water bodies and where direct channels or conduits connect to water bodies, more attention has to be given to manure spreading in order to avoid water contamination. For soils that have a high P concentration (obtained from a soil tests), manure application is not recommended particularly when a surface water body is close by.

This article gives a good review of the situation and the nutrient movement in the soil after spreading. High application rate are a real threat to the environment.