National Soils Database

End of project reportThe objectives of the National Soils Database project were fourfold. The first was to generate a national database of soil geochemistry to complete the work that commenced with a survey of the South East of Ireland carried out in 1995 and 1996 by Teagasc (McGrath and McCormack, 1999). Secondly, to produce point and interpolated spatial distribution maps of major, minor and trace elements and to interpret these with respect to underlying parent material, glacial geology, land use and possible anthropogenic effects. A third objective was to investigate the microbial community structure in a range of soil types to determine the relationship between soil microbiology and chemistry. The final objective was to establish a National Soils Archive

Long-Term Persistence and Leaching of Escherichia coli in Temperate Maritime Soils ▿

Enteropathogen contamination of groundwater, including potable water sources, is a global concern. The spreading on land of animal slurries and manures, which can contain a broad range of pathogenic microorganisms, is considered a major contributor to this contamination. Some of the pathogenic microorganisms applied to soil have been observed to leach through the soil into groundwater, which poses a risk to public health. There is a critical need, therefore, for characterization of pathogen movement through the vadose zone for assessment of the risk to groundwater quality due to agricultural activities. A lysimeter experiment was performed to investigate the effect of soil type and condition on the fate and transport of potential bacterial pathogens, using Escherichia coli as a marker, in four Irish soils (n = 9). Cattle slurry (34 tonnes per ha) was spread on intact soil monoliths (depth, 1 m; diameter, 0.6 m) in the spring and summer. No effect of treatment or the initial soil moisture on the E. coli that leached from the soil was observed. Leaching of E. coli was observed predominantly from one soil type (average, 1.11 ± 0.77 CFU ml−1), a poorly drained Luvic Stagnosol, under natural rainfall conditions, and preferential flow was an important transport mechanism. E. coli was found to have persisted in control soils for more than 9 years, indicating that autochthonous E. coli populations are capable of becoming naturalized in the low-temperature environments of temperate maritime soils and that they can move through soil. This may compromise the use of E. coli as an indicator of fecal pollution of waters in these regions

Evaluating transport risk in soil using dye and bromide tracers

Dye and bromide tracers are established methods of assessing the presence, function, and extent of hydrological pathways in soil. Prediction of E. coli transport pathways in soil, using brilliant blue (BB) dye and bromide tracers, was investigated using in situ field trials on three grassland soil types, under different moisture regimes. Passive transport through preferential flow routes was the dominant mechanism of vertical E. coli transport in the soils studied. However, lateral movement of E. coli from macropores to the soil matrix was also observed. E. coli transport was mainly associated with visualized infiltration patterns but there was some evidence of differential transport of BB and E. coli. Maximum E. coli depth was found not to co-occur with BB and bromide tracers in 44 and 71% of samples, respectively. Soil type and season of application were important in the distribution and maximum depth of E. coli, and the relationship between the bacterium and its tracers. Moisture content was found to be important for the relationship between E. coli and BB, and the extent of this effect varied with soil type. There was a trend of increasing E. coli concentrations to a peak sample moisture concentration of 0.3 to 0.4 g g(-1) dry soil followed by a decrease. Overall BB was found to have greater predictive value than Br. Correlation and co-occurrence analysis found that shortly after land application both BB and Br were good predictors of E. coli transport pathways and distribution under certain conditions, but underestimate risk to shallow groundwater

Evaluating E. coli Transport Risk in Soil using Dye and Bromide Tracers

Peer-reviewedThis is the author's version of a submitted article which was subsequently published in Soil Science Society of America Journal. The definitive version can be found at the journal website, Doi:10.2136/sssaj2011.0250Dye and bromide tracers are established methods of assessing the presence, function, and extent of hydrological pathways in soil. Prediction of E. coli transport pathways in soil, using brilliant blue (BB) dye and bromide tracers, was investigated using in situ field trials on three grassland soil types, under different moisture regimes. Passive transport through preferential flow routes was the dominant mechanism of vertical E. coli transport in the soils studied. However, lateral movement of E. coli from macropores to the soil matrix was also observed. E. coli transport was mainly associated with visualized infiltration patterns but there was some evidence of differential transport of BB and E. coli. Maximum E. coli depth was found not to co-occur with BB and bromide tracers in 44 and 71% of samples, respectively. Soil type and season of application were important in the distribution and maximum depth of E. coli, and the relationship between the bacterium and its tracers. Moisture content was found to be important for the relationship between E. coli and BB, and the extent of this effect varied with soil type. There was a trend of increasing E. coli concentrations to a peak sample moisture concentration of 0.3 to 0.4 g g−1 dry soil followed by a decrease. Overall BB was found to have greater predictive value than Br. Correlation and co-occurrence analysis found that shortly after land application both BB and Br were good predictors of E. coli transport pathways and distribution under certain conditions, but underestimate risk to shallow groundwater

National Soils Database

End of project reportThe objectives of the National Soils Database project were fourfold. The first was to generate a national database of soil geochemistry to complete the work that commenced with a survey of the South East of Ireland carried out in 1995 and 1996 by Teagasc (McGrath and McCormack, 1999). Secondly, to produce point and interpolated spatial distribution maps of major, minor and trace elements and to interpret these with respect to underlying parent material, glacial geology, land use and possible anthropogenic effects. A third objective was to investigate the microbial community structure in a range of soil types to determine the relationship between soil microbiology and chemistry. The final objective was to establish a National Soils Archive