Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Quantify losses of pollutants after application of wastes to land and understand controlling mechanisms - WA0203

WA0203-WA0205. Livestock wastes: reduction of pollution and odour

This study (which comprises WA0203, WA0204 and WA0205) will aim to establish methods for management of livestock wastes in order to avoid pollution, offensive odours and loss of valuable plant nutrients. Factors influencing losses of inorganic and organic pollutants will be investigated following application of livestock wastes to land. Experiments will be designed to quantify N losses from slurries with respect to slurry composition, together with soil and environmental factors, and specially constructed, hydrologically isolated plots will be used to study the horizontal and vertical transfer of pollutants from land to water; drained and undrained plots will be included and provision will be made to determine the volume and composition of water discharged across the surface or from land drains. This approach will be used to identify factors influencing the transport of organic (e.g. faecal coliforms) and inorganic (e.g. N, K and P) pollutants from irrigation of dairy waters, and variables will include the rate, time and frequency of application, which will be examined in relation to waste composition and soil conditions. Grassland management systems based on the utilisation of slurry will be identified and evaluated. Management strategies, designed for soil type and drainage status of particular areas, will be implemented on grassland cut and grazed by cattle. Direct returns to the soil from grazing will be supplemented by addition of plant nutrients through mineral fertiliser and slurry application in either autumn or spring. Strategies will be evaluated by measurement of: N losses as nitrates through ammonia volatilisation and denitrification; apparent recovery of plant nutrients in herbage; and herbage production and animal performance. In addition, methods will be devised for controlling odour formation from wastes, through an understanding of the chemical and microbial processes involved. An extensive review of the literature will be conducted on volatile compounds in wastes and their relationship to human odour perception. A system of small wind tunnels and dynamic dilution olfactometry will be used to seek broad relationships between waste composition and odour; similar studies will be carried out in specially designed chambers, in which environmental conditions are controlled to simulate those existing in piggeries. Larger scale studies will be performed to validate proposals for prevention of farm odour by flushing the slurry channels within a piggery and by formulating pig diets to minimise N excretion. It is anticipated that this work will lead to an improved understanding of N loss in livestock wastes, mechanisms by which pollutants are transported from land to water and processes involved in waste degradation and odour formation.
Time-Scale and Cost
From: 1991

To: 1993

Cost: £184,000
Contractor / Funded Organisations
Institute of Grassland and Environment Research (IGER)
Fields of Study
Environmental Protection - Agriculture