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Constructed wetlands (CWs) have been used to treat agricultural effluents with varying success especially with respect to their operational efficiency in winter and ability to retain phosphorus. Dirty water (DW) from dairy farms is a... more
Constructed wetlands (CWs) have been used to treat agricultural effluents with varying success especially with respect to their operational efficiency in winter and ability to retain phosphorus. Dirty water (DW) from dairy farms is a mixture of manure contaminated runoff and milk parlour washings with a highly polluting biochemical oxygen demand (BOD) < or =3000 mg/L. The initial performance a CW of a 1.2 ha horizontal flow CW consisting of five ponds in series designed to treat DW from a dairy unit was assessed over four years. Ponds were earth-lined and shallow (0.3 m) with a water residence time of 100 days and planted with five species of emergent macrophytes. In comparison to CW inflow, annual reductions were as follows: BOD 99%, P 95% and N 92.8%. Coliforms were reduced by a 10(-5) factor to natural levels. From May to October there was little CW discharge due to evaporative losses. Final effluent quality was poorest in February but remained within a regulatory effluent sta...
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Water quality was measured in 42 streams in the Colebrooke and Upper Bann catchments in Northern Ireland over the period 1990-1998. Despite ongoing pollution control measures, biological water quality, as determined by the invertebrate... more
Water quality was measured in 42 streams in the Colebrooke and Upper Bann catchments in Northern Ireland over the period 1990-1998. Despite ongoing pollution control measures, biological water quality, as determined by the invertebrate average score per taxon (ASPT) index, did not improve and there was no appreciable decline in recorded farm pollution incidents. However, the lack of decline in pollution incidents could reflect changes in detection policy, as a greater proportion of incidents were recorded from less polluting discharges such as farm-yard runoff. In contrast, there was an improvement during 1997 and 1998 in annual chemical water quality classification based on exceedence values (90th percentiles) for dissolved oxygen, ammonium and BOD concentrations. In 1998, 11.9% of streams were severely polluted compared to 26.2% in 1990, while the proportion classed as of salmonid water quality, increased from 40.5% in 1990 to 59.6% in 1998. Although water quality in 1996 did not ...
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ABSTRACT The high nutrient content of poultry litter poses a threat to water quality if managed incorrectly during storage. The aim of this study was to evaluate the transfers of nutrients from four methods of poultry litter heaps storage... more
ABSTRACT The high nutrient content of poultry litter poses a threat to water quality if managed incorrectly during storage. The aim of this study was to evaluate the transfers of nutrients from four methods of poultry litter heaps storage on six arable sites located in Northern Ireland. The methods investigated were; covered heaps, covered heaps with runoff diversion trenches, enveloped heaps, and enveloped heap with runoff diversion trenches. Facilities were installed at each site to capture runoff from the area surrounding the heaps, while changes in nutrient concentration in the soil profile below the heaps were also monitored. Compared to the control plots the presence of the poultry litter heaps did not have a significant impact on the concentrations of total phosphorus (TP) in runoff. However, soil P had a significant positive impact (P = 0.02) on the TP concentrations measured in runoff from plots. There was a significant decrease (P &lt; 0.01) in NO3 and NH4 concentrations in runoff from poultry litter heaps plots. The presence of litter heaps had no impact on conductivity or biological oxygen demand. There was no change in soil P below the heaps however, there was a small increase in soil NO3 concentration at 60–90 cm depth under heaps when compared with the control plots (P &lt; 0.05), which was likely due to elevated soil temperatures under the heaps causing an increase in nitrification. The results demonstrate that poultry litter stored in field heaps poses a minimal risk to water quality if managed carefully.
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Microbial phytases increase the bioavailability of phytate P in poultry diets, and a survey was undertaken to determine if their use had lowered the P composition of broiler litter in Northern Ireland compared with standard values of... more
Microbial phytases increase the bioavailability of phytate P in poultry diets, and a survey was undertaken to determine if their use had lowered the P composition of broiler litter in Northern Ireland compared with standard values of litter composition listed in the current United Kingdom fertilizer recommendations. Litter samples were collected from a total of 20 units across Northern Ireland in 2010 and analyzed for DM, N, phosphate (P2O5), potash (K2O), magnesium oxide (MgO), water-soluble P (WSP), ammonium N (NH4N), and uric acid N. Dry matter of litter was positively correlated (P < 0.001) with N (r(2) = 0.65), P2O5 (r(2) = 0.63), K2O (r(2) = 0.56), and MgO (r(2) = 0.58). Negative correlations were observed between litter DM and WSP (r(2) = 0.45, P < 0.001) and NH4N (r(2) = 0.22, P = 0.038) contents. A standardized litter composition with a 60% DM gave a phosphate content of 13.7 kg/t that was 45% lower than the fertilizer book value (RB209), but there were only slight di...
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ABSTRACT 14C as a tool to trace terrestrial carbon in a complex lake system: implications for food-web structure and carbon cycling
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ABSTRACT Accurate prediction of overland flow requires an understanding of the hydrological processes controlling its occurrence over a range of spatial and temporal scales. This study investigated the factors controlling the initiation... more
ABSTRACT Accurate prediction of overland flow requires an understanding of the hydrological processes controlling its occurrence over a range of spatial and temporal scales. This study investigated the factors controlling the initiation of overland flow from grassland on a drumlin. From January 2003 to December 2006, fine scale monitoring of soil moisture, rainfall and overland flow were carried out at a grazed grassland site in Northern Ireland. Logistic regression analyses were used to identify the factors controlling the initiation of overland flow. Relationships between the observed volumetric soil moisture (VSM) and soil moisture deficit (SMD) values predicted from regional meteorological data were also compared. Results demonstrated that although saturation excess overland flow occurs at this site, 59% of overland flow events occurred on days when soil moisture was below field capacity. The logistic regression analysis confirmed that when soils were below field capacity, average rainfall intensity was the most important variable in determining the probability of overland flow occurring followed by the SMD. Although VSM values at this site were correlated with two sets of modelled values of SMD, one based on the meteorological office rainfall and evaporation calculation system model of the UK Meteorological Office and the other based on a study from Ireland, neither model provided accurate indicators of the risk of overland flow. Each significantly overestimated the number of days when soils were at or above field capacity. This uncertainty and the predicted increase in high-intensity rainfall events as a result of climate change pose challenges to the use of SMD as an indicator of the risk of overland flow.
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... not used in this study. The term RP is used but the database refers to ortho-P, which is assumed to be molybdate RP. The database does not state whether samples are measured on filtered or unfiltered samples. At most of the ...
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... RV Smith,* RH Foy, SD Lennox, C. Jordan, LC Bums, JE Cooper, and RJ Stevens ABSTRACT The Lough Neagh catchment area covers about one-third of the land area of Northern Ireland. This report documents NOr concentra-tions in the major... more
... RV Smith,* RH Foy, SD Lennox, C. Jordan, LC Bums, JE Cooper, and RJ Stevens ABSTRACT The Lough Neagh catchment area covers about one-third of the land area of Northern Ireland. This report documents NOr concentra-tions in the major rivers entering Lough Neagh ...
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Previous studies have reporled that only 40% of nitrite (NO~) major rivers in Northern Ireland originates from land drainage. The remainder appears Io originale from N transformations at the interface between sediment and water within... more
Previous studies have reporled that only 40% of nitrite (NO~) major rivers in Northern Ireland originates from land drainage. The remainder appears Io originale from N transformations at the interface between sediment and water within river systems. Streams in two major river catchments in Northern Ireland were monitored for the presence of NO~-. Mean NO~ concentrations (which all exceeded 3.0
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The Water Framework Directive (WFD) has initiated a shift towards a targeted approach to implementation through its focus on river basin districts as management units and the natural ecological characteristics of waterbodies. Due to its... more
The Water Framework Directive (WFD) has initiated a shift towards a targeted approach to implementation through its focus on river basin districts as management units and the natural ecological characteristics of waterbodies. Due to its role in eutrophication, phosphorus (P) has received considerable attention, resulting in a significant body of research, which now forms the evidence base for the programme of measures (POMs) adopted in WFD River Basin Management Plans (RBMP). Targeting POMs at critical sources areas (CSAs) of P could significantly improve environmental efficiency and cost effectiveness of proposed mitigation strategies. This paper summarises the progress made towards targeting mitigation measures at CSAs in Irish catchments. A review of current research highlights that knowledge related to P export at field scale is relatively comprehensive however; the availability of site-specific data and tools limits widespread identification of CSA at this scale. Increasing complexity of hydrological processes at larger scales limits accurate identification of CSA at catchment scale. Implementation of a tiered approach, using catchment scale tools in conjunction with field-by-field surveys could decrease uncertainty and provide a more practical and cost effective method of delineating CSA in a range of catchments. Despite scientific and practical uncertainties, development of a tiered CSA-based approach to assist in the development of supplementary measures would provide a means of developing catchment-specific and cost-effective programmes of measures for diffuse P. The paper presents a conceptual framework for such an approach, which would have particular relevance for the development of supplementary measures in High Status Waterbodies (HSW). The cost and resources necessary for implementation are justified based on HSWs&#39; value as undisturbed reference condition ecosystems.
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Agricultural pollution incidents in Northern Ireland declined by 51% between 1987 and 1995. This decline resulted from a steady decrease in the largest category of farm pollution, silage effluent, which declined by 78%. The decline in... more
Agricultural pollution incidents in Northern Ireland declined by 51% between 1987 and 1995. This decline resulted from a steady decrease in the largest category of farm pollution, silage effluent, which declined by 78%. The decline in silage pollution was most evident in the months of May and June and may be related to an observed increase in grass wilting, which
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... 3 6 9 12 Effective day length (h) FIG, 3. Relationships bciwecn effective day length (EDL) and chlortiphyil « per unit algal volume (lop panel) and temperature (botlom panel): #. White Lough; O. Lough Neagh, Values shown are month... more
... 3 6 9 12 Effective day length (h) FIG, 3. Relationships bciwecn effective day length (EDL) and chlortiphyil « per unit algal volume (lop panel) and temperature (botlom panel): #. White Lough; O. Lough Neagh, Values shown are month numbers, ie 2=Febniary; 4=April; etc. Page 7. ...
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