End of Project ReportIn recent times there is increasing interest in the hydraulic properties of
free-draining unsaturated soils and on the fate of slurries, sludges, effluents
and fertilisers applied to these soils. This is especially so where relatively
thin soils overlie bedrocks such as limestones with fissures and solution
channels (karstic aquifers). Irish soils are commonly gravelly and stony and
present special problems in determining their hydraulic properties. In this
project, various field and laboratory methods were employed to measure the
hydraulic conductivity of unsaturated gravelly and stony soils overlying
karstic limestone with a watertable 25 m below ground surface at the
Teagasc Centre at Athenry. In parallel with these measurements, cattle and
pig slurries and silage effluents were applied at normal and very heavy rates
in summer and in winter to a series of experimental plots. A chloride tracer
was also used. Rainfall and soil moisture contents and hydraulic potentials
of the soil of the various plots were measured. Samples of soil water were
collected in suction tubes and analysed for nitrate nitrogen (NO3-N). In
addition, samples of groundwater were taken from a nearby well and
analysed for NO3-N and a number of other parameters. Finally, a finite
difference computer model was used to predict contaminant transport to the
groundwater.European Union
Structural Funding (EAGGF
