Reduce Pressure On Watercourses
FINLAND - Jaana Uusi-Kämppä, Senior Research Scientist at MTT Agrifood Research Finland, has demonstrated in her doctoral dissertation that there are many ways in which cattle farms can reduce the load on watercourses caused by cattle-raising.The raising of cattle outdoors, the use of outdoor yards for cattle exercise, and the application of slurry on grass fields cause nitrogen and phosphorus load on watercourses.
Efficient ways of reducing this load include the establishment of buffer zones between the watercourse and the field or other source area, and the replacement of slurry broadcasting with slurry injection. The removal of dung from the outdoor areas used by cattle is also advisable.
Ms Uusi-Kämppä studied loads and ways of reducing them through tests carried out in Jokioinen, Tohmajärvi, Ruukki and Taivalkoski between 1996 and 2008.
Slurry injection works against runoff phosphorus.
Ms Uusi-Kämppä used samples of runoff water and soil to study the nutrient load of forested feeding areas and grass fields. The nitrogen and phosphorus load of runoff water from cattle-raising areas that had been in use for one year corresponded to that of the runoff water of cropped fields. The removal of dung from feeding and bedded areas reduced the nutrient load of the runoff water.
If slurry is broadcast over grass fields, nutrients will find their way into watercourses along the surface of the field. According to the study the injection of slurry into grass fields reduced the amount of total phosphorus in surface runoff waters by 79 per cent and the amount of dissolved phosphorus by 86 per cent. However, in areas of coarse-textured soil there was a risk of the soluble nutrients in injected slurry leaching into the groundwater.
Buffer zones effective on Autumn-tilled soil
Buffer zones between fields and watercourses retain nutrients and sediments contained by surface runoff. Ms Uusi-Kämppä used water and soil samples to study the ability of buffer zones to reduce the nutrient load of cattle farms.
In autumn-tilled soil, buffer zones removed more than half of solids contained by surface runoff, half of total nitrogen and almost one third of total phosphorus. The benefits of buffer zones established between pastures and watercourses were smaller as the nutrient load of pastures is smaller than that of tilled soil.
The dissertation of Ms Uusi-Kämppä for the University of Eastern Finland, “Effect of Outdoor Production, Slurry Management and Buffer Zones on Phosphorus and Nitrogen Runoff Losses from Finnish Cattle Farms”, will be reviewed at MTT Jokioinen in the auditorium of the M building at 12 noon on 6 March 2010. The opponent will be Dr Lillian Øygarden from Bioforsk, the Norwegian Institute for Agricultural and Environmental Research, with Docent Helvi Heinonen-Tanski from the University of Eastern Finland as custodian.
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