This study will aim to quantify factors which affect the fate of biological oxygen demand (BOD) from land applied wastes, with a view to refining the parameters for assessing risks of water pollution for a range of soil types, weather conditions, application rates and types of wastes. Work conducted at IGER North Wyke will involve small scale studies on soil columns and a variable slope experimental rig, in order to establish basic data on the subject. Following this work, field-scale experiments will be set up on a range of soils. These will aim to quantify factors (such as soil type and condition, slope, underdrainage and soil moisture status) which affect risks of direct water pollution, via surface run-off or drain flow, when animal wastes are applied to land at a range of application rates. Once basic data from these experiments have been obtained, additional experiments will be conducted to identify any differences in water pollution risk following land application of different materials, including solid manures, slurry and silage effluent. Results will be of direct practical benefit to the farming industry in defining risks of land application in order to produce farm waste management plans to reduce water pollution, and will be used directly by MAFF for updating Codes of Good Agricultural Practice.