End of Project ReportThe methods, results and discussion of the project are in five
separate sections, 4.1) Phosphorus (P) export from agricultural
grassland with overland flow and drainage water (Johnstown
Castle); 4.2) Phosphorus export from farm in Dripsey catchment,
Co. Cork (NMP); 4.3) Hydrometeorological aspects of farm in
Dripsey Catchment (NMP); 4.4) Phosphorus desorption from Irish
soils; 4.5) National phosphorus model. Most of the field and
laboratory studies were carried out at Johnstown Castle, at UCC
and the field site in the Dripsey catchment.
The main aim of the project was to quantify the loss of P from soil
to water where point source contributions from farmyards were
not high. This involved the construction of hydrologically isolated
field sites where the quantity of overland flow and the P
concentrations for different runoff events from the fields could be
measured. In addition, 90 soil samples representative of Irish
soils were collected and analysed for the different factors
influencing soil adsorption and desorption of P. These results, in
addition to catchment data, were used as a first attempt at
developing a model that could be used to help predict P loss from
soil to water at a catchment scale. The study in the Dripsey was
on a farm where water flow and P levels at two points in a stream
were measured. The hydrometeorology at this site was also
studied. At Johnstown Castle, three overland flow sites, of the
order of one hectare each, and one subsurface flow site were
studied for P loss to water.Environmental Protection Agency
