• Agricultural nutrient surpluses as potential input sources to grow third generation biomass (microalgae): A review

      Fenton, Owen; O hUallachain, Daire (Elsevier, 2012-05)
      Biofuel consumption is increasing and in order to meet EU targets, alternatives to first and second generation biofuels are being examined. The use of micro-algal biomass in the production of biofuel is an area of research which has received attention in recent years. Traditionally, microalgae are commercially grown using synthetic fertilisers, the price of which is linked with rising oil prices. An alternative to the use of inorganic fertiliser is to use surplus agricultural manures in their raw state, bi-products of anaerobic digestion, or runoff and artificial drainage waters, all of which have variable nutrient contents within and across source types. Many studies showed that manures containing a high nutrient content e.g. pig and poultry manures, or bi-products from anaerobic digestion, are potentially viable sources of nutrients to grow algae. Feasibility issues prevail such as variable nutrient contents amongst and across source types, transparency issues and early and sustained nutrient losses during the storage phase. Agitation and efficient nutrient testing before use are important. In Ireland, pig and poultry manures, dairy dirty water, artificial drainage or runoff waters where coupled with agitation during storage to prevent P precipitation and a CO2 source, all have potential to be used in the future.
    • Agriculture, meteorology and water quality in Ireland: a regional evaluation of pressures and pathways of nutrient loss to water

      Schulte, Rogier P.; Richards, Karl G.; Daly, Karen M.; Kurz, I.; McDonald, E.J.; Holden, N.M. (Royal Irish Academy, 31/07/2006)
      The main environmental impact of Irish agriculture on surface and ground water quality is the potential transfer of nutrients to water. Soil water dynamics mediate the transport of nutrients to water, and these dynamics in turn depend on agro-meteorological conditions, which show large variations between regions, seasons and years. In this paper we quantify and map the spatio-temporal variability of agro-meteorological factors that control nutrient pressures and pathways of nutrient loss. Subsequently, we evaluate their impact on the water quality of Irish rivers. For nitrogen, pressure and pathways factors coincide in eastern and southern areas, which is reflected in higher nitrate levels of the rivers in these regions. For phosphorus, pathway factors are most pronounced in north-western parts of the country. In south-eastern parts, high pressure factors result in reduced biological water quality. These regional differences require that farm practices be customised to reflect the local risk of nutrient loss to water. Where pathways for phosphorus loss are present almost year-round—as is the case in most of the north-western part of the country—build-up of pressures should be prevented, or ameliorated where already high. In south-eastern areas, spatio-temporal coincidence of nutrient pressures and pathways should be prevented, which poses challenges to grassland management.
    • The Agrodiversity Experiment: three years of data from a multisite study in intensively managed grasslands

      Kirwan, Laura; Connolly, John; Brophy, Caroline; Baadshaug, Ole; Belanger, Gilles; Black, Alistair D; Camus, Tim; Collins, Rosemary; Cop, Jure; Delgado, Ignacio; De Vliegher, Alex; Elgersma, Anjo; Frankow-Lindberg, Bodil; Golinski, Piotr; Grieu, Philippe; Gustavsson, Anne-Maj; Helgadottir, Aslaug; Hoglind, Mats; Huguenin-Elie, Olivier; Jorgensen, Marit; Kadziuliene, Zydre; Lunnan, Tor; Luscher, Andreas; Kurki, Paivi; Porqueddu, Claudio; Sebastia, M.-Teresa; Thumm, Ulrich; Walmsley, David; Finn, John A.; European Co-Operation in Science and Technology; Irish Research Council for Science, Engineering and Technology; Science Foundation Ireland; 852; 09/RFP/EOB2546 (Ecological Society of America, 11/06/2014)
      Intensively managed grasslands are globally prominent ecosystems. We investigated whether experimental increases in plant diversity in intensively managed grassland communities can increase their resource use efficiency. This work consisted of a coordinated, continental-scale 33-site experiment. The core design was 30 plots, representing 15 grassland communities at two seeding densities. The 15 communities were comprised of four monocultures (two grasses and two legumes) and 11 four-species mixtures that varied in the relative abundance of the four species at sowing. There were 1028 plots in the core experiment, with another 572 plots sown for additional treatments. Sites agreed a protocol and employed the same experimental methods with certain plot management factors, such as seeding rates and number of cuts, determined by local practice. The four species used at a site depended on geographical location, but the species were chosen according to four functional traits: a fast-establishing grass, a slow-establishing persistent grass, a fast-establishing legume, and a slow-establishing persistent legume. As the objective was to maximize yield for intensive grassland production, the species chosen were all high-yielding agronomic species. The data set contains species-specific biomass measurements (yield per species and of weeds) for all harvests for up to four years at 33 sites. Samples of harvested vegetation were also analyzed for forage quality at 26 sites. Analyses showed that the yield of the mixtures exceeded that of the average monoculture in >97% of comparisons. Mixture biomass also exceeded that of the best monoculture (transgressive overyielding) at about 60% of sites. There was also a positive relationship between the diversity of the communities and aboveground biomass that was consistent across sites and persisted for three years. Weed invasion in mixtures was very much less than that in monocultures. These data should be of interest to ecologists studying relationships between diversity and ecosystem function and to agronomists interested in sustainable intensification. The large spatial scale of the sites provides opportunity for analyses across spatial (and temporal) scales. The database can also complement existing databases and meta-analyses on biodiversity–ecosystem function relationships in natural communities by focusing on those same relationships within intensively managed agricultural grasslands.
    • Ammonia emissions from cattle dung, urine and urine with dicyandiamide in a temperate grassland

      Fischer, K.; Burchill, W.; Lanigan, Gary; Kaupenjohann, M.; Chambers, B. J.; Richards, Karl G.; Forrestal, Patrick J.; Department of Agriculture, Food and the Marine, Ireland (Wiley, 03/09/2015)
      Deposition of urine and dung in pasture-based livestock production systems is a major source of ammonia (NH3) volatilization, contributing to the eutrophication and acidification of water bodies and to indirect nitrous oxide emissions. The objectives of this study were to (i) measure NH3 volatilization from dung and urine in three seasons, (ii) test the effect of spiking urine with the nitrification inhibitor dicyandiamide (DCD) on NH3 volatilization and (iii) generate NH3 emission factors (EFs) for dung, urine and urine + DCD in temperate maritime grassland. Accordingly, simulated dung, urine and urine spiked with DCD (at 30 kg DCD/ha equivalent rate) patches were applied to temperate grassland. Treatments were applied three times in 2014 with one measurement of NH3 loss being completed in spring, summer and autumn. The NH3-N EF was highest in spring, which was most likely due to the near absence of rainfall throughout the duration of loss measurement. The EFs across the experiments ranged between 2.8 and 5.3% (mean 3.9%) for dung, 8.7 and 14.9% (mean 11.2%) for urine and 9.5 and 19.5% (mean 12.9%) for urine + DCD, showing that ammonia loss from dung was significantly lower than from urine. Aggregating country-specific emission data such as those from the current experiment with data from climatically similar regions (perhaps in a weighted manner which accounts for the relative abundance of certain environmental conditions) along with modelling is a potentially resource-efficient approach for refining national ammonia inventories.
    • Ammonia emissions from cattle dung, urine and urine with dicyandiamide in a temperate grassland

      Fischer, K.; Burchill, W.; Lanigan, Gary; Kaupenjohann, M.; Chambers, B. J.; Richards, Karl G.; Forrestal, Patrick J.; Department of Agriculture, Food and the Marine, Ireland; RSF13S430; 11S138 (Wiley, 03/09/2015)
      Deposition of urine and dung in pasture-based livestock production systems is a major source of ammonia (NH3) volatilization, contributing to the eutrophication and acidification of water bodies and to indirect nitrous oxide emissions. The objectives of this study were to (i) measure NH3 volatilization from dung and urine in three seasons, (ii) test the effect of spiking urine with the nitrification inhibitor dicyandiamide (DCD) on NH3 volatilization and (iii) generate NH3 emission factors (EFs) for dung, urine and urine + DCD in temperate maritime grassland. Accordingly, simulated dung, urine and urine spiked with DCD (at 30 kg DCD/ha equivalent rate) patches were applied to temperate grassland. Treatments were applied three times in 2014 with one measurement of NH3 loss being completed in spring, summer and autumn. The NH3-N EF was highest in spring, which was most likely due to the near absence of rainfall throughout the duration of loss measurement. The EFs across the experiments ranged between 2.8 and 5.3% (mean 3.9%) for dung, 8.7 and 14.9% (mean 11.2%) for urine and 9.5 and 19.5% (mean 12.9%) for urine + DCD, showing that ammonia loss from dung was significantly lower than from urine. Aggregating country-specific emission data such as those from the current experiment with data from climatically similar regions (perhaps in a weighted manner which accounts for the relative abundance of certain environmental conditions) along with modelling is a potentially resourceefficient approach for refining national ammonia inventories.
    • Ammonia emissions from urea, stabilized urea and calcium ammonium nitrate: insights into loss abatement in temperate grassland

      Forrestal, Patrick J.; Harty, M.; Carolan, R.; Lanigan, Gary; Watson, C.J.; Laughlin, R. J.; McNeil, G.; Chambers, B. J.; Richards, Karl G.; Department of Agriculture, Food and the Marine, Ireland; Teagasc Walsh Fellowship Programme; RSF13S430; 11S138 (Wiley, 17/11/2015)
      Fertilizer nitrogen (N) contributes to ammonia (NH3) emissions, which European Union member states have committed to reduce. This study focused on evaluating NH3-N loss from a suite of N fertilizers over multiple applications, and gained insights into the temporal and seasonal patterns of NH3-N loss from urea in Irish temperate grassland using wind tunnels. The fertilizers evaluated were calcium ammonium nitrate (CAN), urea and urea with the N stabilizers N-(n-butyl) thiophosphoric triamide (NBPT), dicyandiamide (DCD), DCD+NBPT and a maleic and itaconic acid polymer (MIP). 200 (and 400 for urea only) kg N/ha/yr was applied in five equal applications over the growing season at two grassland sites (one for MIP). Mean NH3-N losses from CAN were 85% lower than urea and had highly variable loss (range 45% points). The effect of DCD on NH3 emissions was variable. MIP did not decrease NH3-N loss, but NBPT caused a 78.5% reduction and, when combined with DCD, a 74% reduction compared with urea alone. Mean spring and summer losses from urea were similar, although spring losses were more variable with both the lowest and highest losses. Maximum NH3-N loss usually occurred on the second day after application. These data highlight the potential of stabilized urea to alter urea NH3-N loss outcomes in temperate grassland, the need for caution when using season as a loss risk guide and that urea hydrolysis in temperate grassland initiates quickly. Micrometeorological measurements focused specifically on urea are needed to determine absolute NH3-N loss levels in Irish temperate grassland.
    • Ammonia emissions from urea, stabilized urea and calcium ammonium nitrate: insights into loss abatement in temperate grassland

      Forrestal, Patrick J.; Harty, M.; Carolan, R.; Lanigan, Gary; Watson, C.J.; Laughlin, R. J.; McNeill, G.; Chambers, B.J.; Richards, Karl G.; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine, Ireland; RSF 13S430; 11S138 (Wiley, 17/11/2015)
      Fertilizer nitrogen (N) contributes to ammonia (NH3) emissions, which European Union member states have committed to reduce. This study focused on evaluating NH3-N loss from a suite of N fertilizers over multiple applications, and gained insights into the temporal and seasonal patterns of NH3-N loss from urea in Irish temperate grassland using wind tunnels. The fertilizers evaluated were calcium ammonium nitrate (CAN), urea and urea with the N stabilizers N-(n-butyl) thiophosphoric triamide (NBPT), dicyandiamide (DCD), DCD+NBPT and a maleic and itaconic acid polymer (MIP). 200 (and 400 for urea only) kg N/ha/yr was applied in five equal applications over the growing season at two grassland sites (one for MIP). Mean NH3-N losses from CAN were 85% lower than urea and had highly variable loss (range 45% points). The effect of DCD on NH3 emissions was variable. MIP did not decrease NH3-N loss, but NBPT caused a 78.5% reduction and, when combined with DCD, a 74% reduction compared with urea alone. Mean spring and summer losses from urea were similar, although spring losses were more variable with both the lowest and highest losses. Maximum NH3-N loss usually occurred on the second day after application. These data highlight the potential of stabilized urea to alter urea NH3-N loss outcomes in temperate grassland, the need for caution when using season as a loss risk guide and that urea hydrolysis in temperate grassland initiates quickly. Micrometeorological measurements focused specifically on urea are needed to determine absolute NH3-N loss levels in Irish temperate grassland.
    • Application of Dexter’s soil physical quality index: an Irish case study

      Fenton, Owen; Vero, Sara; Schulte, Rogier P. O.; O'Sullivan, Lilian; Bondi, G.; Creamer, Rachel E.; Department of Agriculture, Food and the Marine, Ireland; 6582 (Teagasc (Agriculture and Food Development Authority), Ireland, 26/08/2017)
      Historically, due to a lack of measured soil physical data, the quality of Irish soils was relatively unknown. Herein, we investigate the physical quality of the national representative profiles of Co. Waterford. To do this, the soil physical quality (SPQ) S-Index, as described by Dexter (2004a,b,c) using the S-theory (which seeks the inflection point of a soil water retention curve [SWRC]), is used. This can be determined using simple (S-Indirect) or complex (S-Direct) soil physical data streams. Both are achievable using existing data for the County Waterford profiles, but until now, the suitability of this S-Index for Irish soils has never been tested. Indirect-S provides a generic characterisation of SPQ for a particular soil horizon, using simplified and modelled information (e.g. texture and SWRC derived from pedo-transfer functions), whereas Direct-S provides more complex site-specific information (e.g. texture and SWRC measured in the laboratory), which relates to properties measured for that exact soil horizon. Results showed a significant correlation between S-Indirect (Si) and S-Direct (Sd). Therefore, the S-Index can be used in Irish soils and presents opportunities for the use of Si at the national scale. Outlier horizons contained >6% organic carbon (OC) and bulk density (Bd) values <1 g/cm3 and were not suitable for Si estimation. In addition, the S-Index did not perform well on excessively drained soils. Overall correlations of Si. with Bd and of Si. with OC% for the dataset were detected. Future work should extend this approach to the national scale dataset in the Irish Soil Information System.
    • Atypical Listeria innocua strains possess an intact LIPI-3

      Clayton, Evelyn M; Daly, Karen M.; Guinane, Caitriona M.; Hill, Colin; Cotter, Paul D.; Ross, R Paul; Enterprise Ireland; Science Foundation Ireland; 06/IN.1/B98; 10/IN.1/B3027 (Biomed Central, 08/03/2014)
      Background: Listeria monocytogenes is a food-borne pathogen which is the causative agent of listeriosis and can be divided into three evolutionary lineages I, II and III. While all strains possess the well established virulence factors associated with the Listeria pathogenicity island I (LIPI-1), lineage I strains also possess an additional pathogenicity island designated LIPI-3 which encodes listeriolysin S (LLS), a post-translationally modified cytolytic peptide. Up until now, this pathogenicity island has been identified exclusively in a subset of lineage I isolates of the pathogen Listeria monocytogenes. Results: In total 64 L. innocua strains were screened for the presence of LIPI-3. Here we report the identification of an intact LIPI-3 in 11 isolates of L. innocua and the remnants of the cluster in several others. Significantly, we can reveal that placing the L. innocua lls genes under the control of a constitutive promoter results in a haemolytic phenotype, confirming that the cluster is capable of encoding a functional haemolysin. Conclusions: Although the presence of the LIPI-3 gene cluster is confined to lineage I isolates of L. monocytogenes, a corresponding gene cluster or its remnants have been identified in many L. innocua strains.
    • Botanical rejuvenation of field margins and benefits for invertebrate fauna on a drystock farm in County Longford

      Sheridan, H.; Finn, John A.; O'Donovan, G.; Teagasc Walsh Fellowship Programme (Royal Irish Academy, 30/07/2009)
      This study investigates methods to rejuvenate the fl ora of previously degraded fi eld margins on a pastoral farm in County Longford. We also assess the effects of individual treatments on the abundance of various orders of invertebrates recorded within the experimental plots. Field margin treatments were 1.5m-wide unfenced control margins, 1.5m-wide fenced margins or 3.5m-wide fenced margins. Nutrient inputs were excluded from all of the experimental plots. The botanical composition of the plots was examined on four occasions between 2002 and 2004 using permanent, nested quadrats. Emergence traps were used to measure invertebrate abundance within treatment plots and the main sward. Results indicated that 1) exclusion of nutrient inputs had a positive effect on plant species richness within the fi eld margins; 2) plant species richness decreased with increased distance from the hedgerow; 3) herb species richness was greatest in the 1.5m closest to the hedgerow; 4) greater abundance of invertebrates occurred within the 3.5m-wide margins; 5) successful control of Pteridium aquilinum was achieved through spot treatment with the selective herbicide ‘Asulox’; and 6) a combination of management techniques such as cutting and grazing is likely to enhance plant species richness and facilitate the structural diversity of vegetation that is necessary for many invertebrate taxa.
    • Can the agronomic performance of urea equal calcium ammonium nitrate across nitrogen rates in temperate grassland?

      Forrestal, Patrick J.; Harty, M.A.; Carolan, R.; Watson, C.J.; Lanigan, Gary; Wall, D.P.; Hennessy, Deirdre; Richards, Karl G.; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine, Ireland; Department of Agriculture, Environment and Rural Affairs, Northern Ireland (Wiley, 23/03/2017)
      In temperate grassland, urea has been shown to have lower nitrous oxide emissions compared to ammonium nitrate-based fertilizer and is less expensive. However, nitrogen (N) loss via ammonia volatilization from urea raises questions regarding yield performance and efficiency. This study compares the yield and N offtake of grass fertilized with urea, calcium ammonium nitrate (CAN) and urea treated with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) at six site-years. Five annual fertilizer N rates (100–500 kg N/ha) were applied in five equal splits of 20–100 kg N/ha during the growing season. On average, urea produced slightly better yields than CAN in spring (103.5% of CAN yield) and slightly poorer yields in summer (98.4% of CAN yield). There was no significant difference in annual grass yield between urea, CAN and urea + NBPT. Urea had the lowest cost per tonne of DM grass yield produced. However, the urea treatment had lower N offtake than CAN and this difference was more pronounced as the N rate increased. There was no difference in N offtake between urea + NBPT and CAN. While this study shows that urea produced yields comparable to CAN, urea apparent fertilizer N recovery (AFNR) tends to be lower. Urea selection in place of CAN will increase national ammonia emissions which is problematic for countries with targets to reduce ammonia emissions. Promisingly, NBPT allows the agronomic performance of urea to consistently equal CAN across N rates by addressing the ammonia loss limitations of urea.
    • Carbon and nitrogen dynamics and greenhouse gas emissions in constructed wetlands treating wastewater: a review

      Department of Agriculture, Food and the Marine; Jahangir, M.M.R.; Richards, Karl G.; Healy, M. G.; Gill, L.; Muller, C.; Johnston, P.; Fenton, Owen; Irish Research Council; Department of Agriculture, Food and the Marine, Ireland (European Geosciences Union, 18/01/2016)
      The removal efficiency of carbon (C) and nitrogen (N) in constructed wetlands (CWs) is very inconsistent and frequently does not reveal whether the removal processes are due to physical attenuation or whether the different species have been transformed to other reactive forms. Previous research on nutrient removal in CWs did not consider the dynamics of pollution swapping (the increase of one pollutant as a result of a measure introduced to reduce a different pollutant) driven by transformational processes within and around the system. This paper aims to address this knowledge gap by reviewing the biogeochemical dynamics and fate of C and N in CWs and their potential impact on the environment, and by presenting novel ways in which these knowledge gaps may be eliminated. Nutrient removal in CWs varies with the type of CW, vegetation, climate, season, geographical region, and management practices. Horizontal flow CWs tend to have good nitrate (NO3−) removal, as they provide good conditions for denitrification, but cannot remove ammonium (NH4+) due to limited ability to nitrify NH4+. Vertical flow CWs have good NH4+ removal, but their denitrification ability is low. Surface flow CWs decrease nitrous oxide (N2O) emissions but increase methane (CH4) emissions; subsurface flow CWs increase N2O and carbon dioxide (CO2) emissions, but decrease CH4 emissions. Mixed species of vegetation perform better than monocultures in increasing C and N removal and decreasing greenhouse gas (GHG) emissions, but empirical evidence is still scarce. Lower hydraulic loadings with higher hydraulic retention times enhance nutrient removal, but more empirical evidence is required to determine an optimum design. A conceptual model highlighting the current state of knowledge is presented and experimental work that should be undertaken to address knowledge gaps across CWs, vegetation and wastewater types, hydraulic loading rates and regimes, and retention times, is suggested. We recommend that further research on process-based C and N removal and on the balancing of end products into reactive and benign forms is critical to the assessment of the environmental performance of CWs.
    • Carbon and nitrogen dynamics: Greenhouse gases in groundwater beneath a constructed wetland treating municipal wastewater

      Jahangir, Mohammad M. R.; Richards, Karl G.; Fenton, Owen; Carroll, Paul; Harrington, Rory; Johnston, Paul (ESAI, 26/02/2014)
      Constructed wetlands (CW) act as nitrogen (N) sinks and reactors facilitating a number of physical, chemical and biological processes. The N removal efficiency of through-flowing water in such systems when used to treat municipal wastewater is variable. Their overall removal efficiencies do not specifically explain which N species have been removed by physical attenuation, and by biological assimilation or transformation to other forms. A wider understanding of how N removal occurs would help elucidate how losses of N and associated gases from CW impact on water and air quality. The objective of this study is to investigate the C and N cycling processes in the porewater of soils immediately adjacent, up-gradient and down- gradient to helophyte —vegetated CW cells.
    • Carbon cycling in temperate grassland under elevated temperature

      Jansen-Willems, Anne B.; Lanigan, Gary; Grunhage, Ludger; Muller, Christoph; Department of Agriculture, Food and the Marine, Ireland; Teagasc Walsh Fellowship Programme; RSF 10/SC/716 (Wiley, 01/11/2016)
      An increase in mean soil surface temperature has been observed over the last century, and it is predicted to further increase in the future. The effect of increased temperature on ecosystem carbon fluxes in a permanent temperate grassland was studied in a long-term (6 years) field experiment, using multiple temperature increments induced by IR lamps. Ecosystem respiration (R-eco) and net ecosystem exchange (NEE) were measured and modeled by a modified Lloyd and Taylor model including a soil moisture component for R-eco (average R2 of 0.78) and inclusion of a photosynthetic component based on temperature and radiation for NEE (R2 = 0.65). Modeled NEE values ranged between 2.3 and 5.3 kg CO2 m−2 year−1, depending on treatment. An increase of 2 or 3°C led to increased carbon losses, lowering the carbon storage potential by around 4 tonnes of C ha−1 year−1. The majority of significant NEE differences were found during night-time compared to daytime. This suggests that during daytime the increased respiration could be offset by an increase in photosynthetic uptake. This was also supported by differences in δ13C and δ18O, indicating prolonged increased photosynthetic activity associated with the higher temperature treatments. However, this increase in photosynthesis was insufficient to counteract the 24 h increase in respiration, explaining the higher CO2 emissions due to elevated temperature.
    • Characterization of Environmentally Persistent Escherichia coli Isolates Leached from an Irish Soil

      Brennan, Fiona P.; Abram, Florence; Chinalia, Fabio A.; Richards, Karl G.; O'Flaherty, Vincent; Irish Research Council for Science, Engineering and Technology; Science Foundation Ireland (American Society for Microbiology, 12/02/2010)
      Soils are typically considered to be suboptimal environments for enteric organisms, but there is increasing evidence that Escherichia coli populations can become resident in soil under favorable conditions. Previous work reported the growth of autochthonous E. coli in a maritime temperate Luvic Stagnosol soil, and this study aimed to characterize, by molecular and physiological means, the genetic diversity and physiology of environmentally persistent E. coli isolates leached from the soil. Molecular analysis (16S rRNA sequencing, enterobacterial repetitive intergenic consensus PCR, pulsed-field gel electrophoresis, and a multiplex PCR method) established the genetic diversity of the isolates (n = 7), while physiological methods determined the metabolic capability and environmental fitness of the isolates, relative to those of laboratory strains, under the conditions tested. Genotypic analysis indicated that the leached isolates do not form a single genetic grouping but that multiple genotypic groups are capable of surviving and proliferating in this environment. In physiological studies, environmental isolates grew well across a broad range of temperatures and media, in comparison with the growth of laboratory strains. These findings suggest that certain E. coli strains may have the ability to colonize and adapt to soil conditions. The resulting lack of fecal specificity has implications for the use of E. coli as an indicator of fecal pollution in the environment.
    • Chemical amendment of pig slurry: control of runoff related risks due to episodic rainfall events up to 48 h after application

      O'Flynn, Cornelius J.; Healy, Mark G.; Wilson, Paul; Hoekstra, Nyncke J.; Troy, Shane M.; Fenton, Owen; Irish Research Council for Science, Engineering and Technology (Springer, 01/09/2013)
      Losses of phosphorus (P) from soil and slurry during episodic rainfall events can contribute to eutrophication of surface water. However, chemical amendments have the potential to decrease P and suspended solids (SS) losses from land application of slurry. Current legislation attempts to avoid losses to a water body by prohibiting slurry spreading when heavy rainfall is forecast within 48 h. Therefore, in some climatic regions, slurry spreading opportunities may be limited. The current study examined the impact of three time intervals (TIs; 12, 24 and 48 h) between pig slurry application and simulated rainfall with an intensity of 11.0±0.59 mm h-1. Intact grassed soil samples, 1 m long, 0.225 m wide and 0.05 m deep, were placed in runoff boxes and pig slurry or amended pig slurry was applied to the soil surface. The amendments examined were: (1) commercial-grade liquid alum (8% Al2O3) applied at a rate of 0.88:1 [Al/total phosphorus (TP)] (2) commercial-grade liquid ferric chloride (38% FeCl3) applied at a rate of 0.89:1 [Fe/TP] and (3) commercial-grade liquid poly-aluminium chloride (10 % Al2O3) applied at a rate of 0.72:1 [Al/TP]. Results showed that an increased TI between slurry application and rainfall led to decreased P and SS losses in runoff, confirming that the prohibition of land-spreading slurry if heavy rain is forecast in the next 48 h is justified. Averaged over the three TIs, the addition of amendment reduced all types of P losses to concentrations significantly different (p<0.05) to those from unamended slurry, with no significant difference between treatments. Losses from amended slurry with a TI of 12 h were less than from unamended slurry with a TI of 48 h, indicating that chemical amendment of slurry may be more effective at ameliorating P loss in runoff than current TI-based legislation. Due to the high cost of amendments, their incorporation into existing management practices can only be justified on a targeted basis where inherent soil characteristics deem their usage suitable to receive amended slurry.
    • The composition of dirty water on dairy farms in Ireland

      Martinez-Suller, L.; Provolo, G.; Carton, Owen T.; Brennan, D.; Kirwan, Laura; Richards, Karl G. (Teagasc, 2010)
      Considerable quantities of dirty water, composed of milking parlour wash-water, milk spillages, runoff from cattle yard areas and, possibly, effluent from silage and manure, are produced on dairy farms. In Ireland, dirty water from dairy farm facilities is normally managed by spreading on, or irrigation to, land. It has considerable potential to cause water pollution due to its high pH, 5-day biochemical oxygen demand and its N and P concentrations. The objective of the present study was to contribute to better management of dirty water on dairy farms by providing estimates of its composition using rapid methods that can be easily used on farms. During the experiment, 34 samples were collected from the facilities on the dairy farm at Teagasc, Johnstown Castle (Wexford), between 27 January and 1 May, 2006. Dry matter and specific gravity provided the best indicator of biochemical oxygen demand, total nitrogen and phosphorous, and micro and macro nutrients. The nutrient concentration of dirty water can be determined rapidly using either dry matter concentration or specific gravity, enabling farmers to include this information in the nutrient management plan for their farm.
    • Compositional Changes in the Hydrophobic acids fraction of Drainage Water from Different Land Management Practices

      Byrne, Corinna M. P.; Hayes, Michael M. B.; Kumar, Rajeev; Novotny, Etelvino H.; Lanigan, Gary; Richards, Karl G.; Fay, Deirdre; Simpson, Andre J. (Elsevier B. V., 2010-08)
      Dissolved organic matter (DOM) can play a key role in many environmental processes, including carbon cycling, nutrient transport and the fates of contaminants and of agrochemicals. Hydrophobic acids (Ho), the major components of the DOM, were recovered from the drainage waters from well-drained (WDS) and poorly-drained (PDS) Irish grassland soils in lysimeters, amended with N fertiliser (F) and with bovine urine (U) and were studied using 1D and 2D solution-state Nuclear Magnetic Resonance (NMR) spectroscopy. The Diffusion Edited (DE) 1H NMR spectra indicated that the Ho consisted largely of larger molecules, or of molecules that formed rigid aggregates, and the 1D and the 2D (Heteronuclear Multiple Quantum Coherence – HMQC, the Total Correlation Spectroscopy – TOCSY, and the Nuclear Overhauser Effect – NOESY) spectra indicated that the samples were composed of lignin residues, carbohydrates, protein/peptides, and aliphatic components derived from plant waxes/cuticular materials and from microbial lipids. The F amendments increased the concentrations of Ho in the waters by 1.5 and 2.5 times those in the controls in the cases of WDS and PDS, respectively. The lignin-derived components were increased by 50% and 300% in the cases of the Ho from the WDS and PDS, respectively. Applications of F + U decreased the losses of Ho, (compared to the F amendments alone) and very significantly decreased those of the lignin-derived materials, indicating that enhanced microbial activity from U gave rise to enhanced metabolism of the Ho components, and especially of lignin. In contrast the less biodegradable aliphatic components containing cuticular materials increased as the result of applications of F + U. This study helps our understanding of how management practices influence the movement of C between terrestrial and aquatic environments.
    • Confirmation of co-denitrification in grazed grassland

      Selbie, Diana R.; Lanigan, Gary; Laughlin, Ronald J.; Di, Hong J.; Moir, James L.; Cameron, Keith C.; Clough, Tim J.; Watson, Catherine J.; Grant, Jim; Somers, Cathal; Richards, Karl G.; Department of Agriculture, Food and the Marine, Ireland; Teagasc Walsh Fellowship Programme; RSF 07536 (Nature Publishing Group, 30/11/2015)
      Pasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment. Research has focused on losses to air and water due to the health, economic and environmental impacts of reactive N. Di-nitrogen (N2) emissions are still poorly characterized, both in terms of the processes involved and their magnitude, due to financial and methodological constraints. Relatively few studies have focused on quantifying N2 losses in vivo and fewer still have examined the relative contribution of the different N2 emission processes, particularly in grazed pastures. We used a combination of a high 15N isotopic enrichment of applied N with a high precision of determination of 15N isotopic enrichment by isotope-ratio mass spectrometry to measure N2 emissions in the field. We report that 55.8 g N m−2 (95%, CI 38 to 77 g m−2) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m−2), compared to only 1.1 g N m−2 (0.4 to 2.8 g m−2) from denitrification. This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.
    • Conserving Farmland Biodiversity – Lessons learned and future prospects

      O hUallachain, Daire; Finn, John A. (School of Agriculture, Food Science and Veterinary Medicine, University College Dublin in association with Teagasc, 2011)
      A conference Conserving Farmland Biodiversity: Lessons learned and future prospects was held in Wexford, Ireland on the 25th and 26th of May 2011. Through a combination of keynote presentations and theatre presentations, delegates were informed of latest developments in policy and research relevant to farmland biodiversity in Ireland. Four main broad categories dominated the content of the conference: agricultural policy, agri-environment schemes, High Nature Value farming systems, and a variety of case studies that assessed the success of specific conservation actions. As the European Union refocuses its commitment to halting biodiversity loss, reform of the post-2013 CAP is proceeding with an increased emphasis on environmental goals. This conference provided a timely discussion of these policies, and the conservation needs and actions for Irish habitats and species. Here we provide a summary of the main themes and issues presented at the conference.