• N leaching to groundwater from dairy production involving grazing over the winter on a clay-loam soil

      Necpalova, Magdalena; Fenton, Owen; Casey, I.; Humphreys, James (Elsevier B. V., 2012-08-15)
      This study investigated concentrations of various N species in shallow groundwater (< 2.2 m below ground level) and N losses from dairy production involving grazing over the winter period on a clay loam soil with a high natural attenuation capacity in southern Ireland (52˚51’N, 08˚21’W) over a two year period. A dense network of shallow groundwater piezometers was installed to determine groundwater flow direction and N spatial and temporal variation. Estimated vertical travel times through the unsaturated zone (<0.5 yr, time lag) allowed the correlation of management with groundwater N within a short space of time. There was a two way interaction of the system and sampling date (P < 0.05) on concentrations of DON, oxidised N and NO3--N. In contrast, concentrations of NH4+-N and NO2--N were unaffected by the dairy system. Grazing over the winter had no effect on N losses to groundwater. Mean concentrations of DON, NH4+-N, NO2--N and NO3--N were 2.16, 0.35, 0.01 and 0.37 mg L-1 respectively. Soil attenuation processes such as denitrification and DNRA resulted in increased NH4+-N levels. For this reason, DON and NH4+-N represented the highest proportion of N losses from the site. Some of the spatial and temporal variation of N concentrations was explained by correlations with selected chemical and hydro-topographical parameters (NO3--N/Cl- ratio, distance of the sampling point from the closest receptor, watertable depth, depth of sampling piezometer, DOC concentration). A high explanatory power of NO3--N/Cl- ratio and the distance of the sampling point from the closest receptor indicated the influence of point sources and groundwater-surface water interactions.
    • N-3 Polyunsaturated Fatty Acids (PUFAs) Reverse the Impact of Early-Life Stress on the Gut Microbiota

      Pusceddu, Matteo M; El Aidy, Sahar; Crispie, Fiona; O'Sullivan, Orla; Cotter, Paul; Stanton, Catherine; Kelly, Philip M.; Cryan, John F.; Dinan, Timothy G. (PLOS, 2015-10-01)
      Background Early life stress is a risk factor for many psychiatric disorders ranging from depression to anxiety. Stress, especially during early life, can induce dysbiosis in the gut microbiota, the key modulators of the bidirectional signalling pathways in the gut-brain axis that underline several neurodevelopmental and psychiatric disorders. Despite their critical role in the development and function of the central nervous system, the effect of n-3 polyunsaturated fatty acids (n-3 PUFAs) on the regulation of gut-microbiota in early-life stress has not been explored. Methods and Results Here, we show that long-term supplementation of eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) (80% EPA, 20% DHA) n-3 PUFAs mixture could restore the disturbed gut-microbiota composition of maternally separated (MS) female rats. Sprague-Dawley female rats were subjected to an early-life stress, maternal separation procedure from postnatal days 2 to 12. Non-separated (NS) and MS rats were administered saline, EPA/DHA 0.4 g/kg/day or EPA/DHA 1 g/kg/day, respectively. Analysis of the gut microbiota in adult rats revealed that EPA/DHA changes composition in the MS, and to a lesser extent the NS rats, and was associated with attenuation of the corticosterone response to acute stress. Conclusions In conclusion, EPA/DHA intervention alters the gut microbiota composition of both neurodevelopmentally normal and early-life stressed animals. This study offers insights into the interaction between n-3 PUFAs and gut microbes, which may play an important role in advancing our understanding of disorders of mood and cognitive functioning, such as anxiety and depression.
    • National Soils Database

      Fay, Deirdre; McGrath, David; Zhang, Chaosheng; Carrigg, Cora; O’Flaherty, Vincent; Kramers, Gaelene; Carton, Owen T.; Grennan, Eamonn (Teagasc, 2007-07-01)
      The 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.
    • A nationwide surveillance study on E.coli 0157:H7 and enterobacteriaceae in Irish minced beef products

      Duffy, Geraldine; Cagney, Claire; Crowley, Helen; Sheridan, James J. (Teagasc, 2003-04)
      A surveillance study on prevalence and numbers of E . coli O157: H7 in minced beef (unpackaged or packaged) and beefburgers (frozen, fresh and unpackaged or packaged) was carried out over a period of 12 months in the Republic of Ireland. A total of 1533 products were tested with approximately 15 products collected from each of the 26 counties every 3 months. Mince and beefburgers were collected from both supermarkets and butcher shop outlets. A standard analysis was conducted by sample enrichment, IMS extraction and plating onto SMAC agar with confirmation by PCR. The results showed that 43 retail beef products (2.8 %) contained E .coli O157:H7. The number of E .coli O157: H7 in 21 of these samples ranged from log100.51 - 4.03 cfu g-1 ( i.e. 3 to 10,700 bacteria per gram) while in the remaining 22 the pathogen was detectable by enrichment only. There was a seasonal effect observed with 33 of 43 positive samples detected in January (n = 8), April /May(n=20) and August (n=5) and the remaining 10 positive samples detected over the other 8 months. Of the beef products testing positive, 32 were purchased from supermarkets and 11 from butcher shops. E .coli O157:H7 was recovered from 2.8% (13 / 457) of fresh packaged mince and from 1.88 % (3 / 160) of fresh unpackaged burgers purchased from butcher shops. Of the 43 isolates recovered, 41 contained the virulence genes v t1, v t2, E aeA and H lyA while the remaining 2 isolates contained only one of the vtproducing genes (v t1or v t2).
    • A nationwide survey of anthelmintic treatment failure on sheep farms in Ireland

      Keegan, Jason D; Keane, Orla M; Good, Barbara; De Waal, Theo; Denny, Marian; Hanrahan, James P; Fitzgerald, William; Sheehan, Maresa (Biomed Central, 2017-02-09)
      Background Between 2013 and 2015 the Department of Agriculture, Food and the Marine (DAFM) administered a sheep technology adoption programme (STAP), with the aim of increasing profitability on Irish sheep farms by encouraging the adoption of best management practices. One of the options available to STAP participants was to test the efficacy of the anthelmintic treatment (benzimadazole, levamisole or macrocyclic lactone) used in their flocks by means of a drench test, which is a modification of the faecal egg count reduction test; individual faecal samples were collected from the same group of lambs before and after anthelmintic treatment, the number of eggs present pre and post treatment was subsequently determined from a pooled sample. Results In total, 4211 drench tests were undertaken by farmers during the 3 years of the programme. Information on the anthelmintic product used was available for 3771 of these tests; anthelmintics from the classes benzimidazole (BZ), levamisole (LV) and macrocyclic lactone (ML) (avermectins (AVM) plus moxidectin (MOX)) were used in 42.0%, 23.4% and 32.5% of tests, respectively. The remaining 2.1% of tests involved an inappropriate product. The efficacy of treatment against ‘other trichostrongyles’ (excluding Nematodirus spp and Strongyloides papillosus.) could be established for 1446 tests, and 51% of these tests were considered effective (i.e. a reduction of faecal egg count (FEC) ≥ 95%). There was a significant difference among the drug groups in efficacy; 31.5%, 51.9%, 62.5% and 84% of treatments were considered effective for BZ, LV, AVM, MOX, respectively. The efficacy of treatment against Nematodirus spp. could be established for 338 tests and the overall efficacy was 96%. Conclusions Due to the significant difference among the anthelmintic classes for efficacy against ‘other trichostrongyles’ along with the high level of efficacy against Nematodirus spp., a genus for which anthelmintic resistance is rarely reported, it is concluded that anthelmintic resistance was responsible for the majority of the anthelmintic treatment failures observed.
    • Near infra-red spectroscopy in the food industry: a tool for quality management

      Downey, Gerard (Teagasc, 1999-03)
      Near infrared (NIR) spectroscopy is a rapid, non-destructive analytical technique which has been used in the food and agriculture industries for almost 20 years. Ireland was one of the first countries in the world to adopt this method for national trading purposes and the grain trade has used it for off-farm and in-process analysis since 1981. However, other sectors have been slower to realise its potential and as part of a process of demonstrating the role which it may play in monitoring quality in a range of food industry applications, a programme of research and development has been on-going within Teagasc and its predecessor An Foras Talúntais.
    • Near Infrared Spectroscopy in the Food Industry: A Tool of Quality Management.

      Downey, Gerard (Teagasc, 1999-03-01)
      Near infrared (NIR) spectroscopy is a rapid, non-destructive analytical technique which has been used in the food and agriculture industries for almost 20 years. Ireland was one of the first countries in the world to adopt this method for national trading purposes and the grain trade has used it for off-farm and in-process analysis since 1981. However, other sectors have been slower to realise its potential and as part of a process of demonstrating the role which it may play in monitoring quality in a range of food industry applications, a programme of research and development has been on-going within Teagasc and its predecessor An Foras Talúntais. NIR spectroscopy provides the food processor with information. This information may describe how much of a given substance is present in a mixture or how the overall quality of the substance compares to a reference material e.g. a previous batch of raw material, finished goods or a competitor’s product. This report provides some examples of precompetitive R&D on representative qualitative and quantitative problems in a range of foods and food ingredients. The use of NIR spectra collected within 24 hours of slaughter to predict beef tenderness 14 days later shows considerable promise. Non-destructive monitoring of flesh composition in farmed salmon has paved the way for the efficient use of expensive feed materials while the content of each species in binary mixtures of minced beef and lamb has been accurate enough to suggest the use of NIR spectroscopy as a rapid screening tool by regulatory agencies, food processors and retailers. Classification of a range of food ingredients (including skim milk powder and flour) into one of a number of functionally-discrete categories has been successfully achieved with levels of accuracy high enough to warrant immediate industry utilisation i.e. greater than 90% for skim milk powders and 97% in the case of flour. Species confirmation in a number of raw minced meats (chicken, turkey, pork, beef and lamb) has been achieved with over 90% accuracy in feasibility studies. Calibrations transferred from one NIR instrument to another lose accuracy because of differences in instrument construction, sample presentation and other factors. A research effort has recently been applied to this problem of transferability and results are available for both scanning and fixed filter instruments. The success achieved opens the way for using NIR results obtained in different companies or countries as an uncontested basis for trade.
    • Nematode control in suckler beef cattle over their first two grazing seasons using a targeted selective treatment approach

      O’Shaughnessy, James; Earley, Bernadette; Mee, John F; Doherty, Michael L; Crosson, Paul; Barrett, Damien; de Waal, Theo (Biomed Central, 2015-06-18)
      Background With concerns over the development of anthelmintic resistance in cattle nematode populations, we must re-examine our approach to nematode control in cattle. Targeted selective treatments (TST), whereby individual animals are treated instead of entire groups, are being investigated as an alternative. The study objective was to determine if anthelmintic usage could be reduced using a TST-based approach to nematode control in spring-born suckler beef cattle over their first and second grazing seasons (SGS) without affecting performance. In the first grazing season (FGS), 99 calves with an initial mean (s.d.) calf age and live weight on day 0 (June 28th 2012) of 107 (23.1) days and 160 (32.5) kg, respectively, were used. The study commenced on day 0 when calves were randomised and allocated to one of two treatments; 1), standard treatment (control) and 2), TST. Control calves were treated subcutaneously with ivermectin on days 0, 41 and 82 in the FGS. All calves were treated with ivermectin on day 124 and housed on day 133. In the SGS, only heifer calves from the FGS were used and control heifers were treated with ivermectin on day 393. Animals were weighed, blood and faecal sampled every three weeks. The TST animals were treated with ivermectin if thresholds based on a combination of plasma pepsinogen concentrations, faecal egg count and/or the presence of Dictyocaulus viviparus larvae in faeces (FGS only) were reached. Results No TST calves reached the treatment threshold criteria in the FGS. The FGS average daily live weight gain (ADG ± s.e.m.) for control and TST group calves was 0.89 ± 0.02 kg and 0.94 ± 0.02 kg day−1, respectively (P = 0.17). In the SGS, all heifers were treated with ivermectin on day 431 due to clinical signs of respiratory disease. The ADG for control and TST heifers from turnout on day 321 to day 431 was 0.90 ± 0.04 and 0.80 ± 0.04 kg day−1, respectively (P = 0.03). Conclusions Spring-born FGS suckler beef calves require minimal anthelmintic treatment to maintain performance. In contrast, clinical parasitic disease may develop in the SGS unless appropriate anthelmintic treatment is provided.
    • A New Direction for the Payment of Milk: Technological and Seasonality Considerations in Multiple Component Milk Pricing of Milk (Liquid and Manufacturing) for a Diversifying Dairy Industry

      Breen, James; Wallace, Michael; Crosse, Seamus; O'Callaghan, Donal (Teagasc, 2007-01-01)
      The main objectives of this study were to compare a Multiple Component Pricing system with the current milk pricing practice in Ireland and to estimate the marginal values of the three main milk components (fat, protein and lactose) in the context of the Irish milk processing industry. A representative linear programming model of an average Irish milk processor was developed in order to determine the marginal values of the milk components and to compare the value of milk under the Multiple Component Pricing system with the value under the current milk pricing practice. This study also examined the effect of product mix, milk supply and milk composition on the marginal value of the milk components.
    • New Insights into Cell Encapsulation and the Role of Proteins During Flow Cytometry

      Doherty, Sinead B.; Brodkorb, Andre (Intech, 2012-06-13)
      Modern approaches to science tend to follow divergent paths. On one hand, instruments and technologies are developed to capture as much information as possible with the need for complex data analysis to identify problematic issues. On the other hand, formulation focused, minimalistic approaches that gather only the most pertinent data for specific questions also represent a powerful methodology. This chapter will provide many examples of the latter by integrating Flow Cytometry (FACS - Fluorescence-Activated Cell Sorting) technology with high throughput screening (HTS) of encapsulation systems with extensive utility of one-dimensional (1-D) imaging for protein localisation. In this regard, less information is acquired from each cell, data files will be more manageable, easier to analyse and throughput screening will be significantly enhanced beyond traditional HTS analysis, irrespective of the protein concentration present in the background or delivery media.
    • New product development opportunities for Irish companies in the British cheese market

      Cowan, Cathal; Downey, Gerard (Teagasc, 2008-11)
      The primary objective of this research was to identify innovative cheese concepts appropriate for UK consumers and suitable for Irish industry to manufacture. It also aimed to identify personal, situational and market factors that influence consumers when purchasing cheese. This research study used existing market literature, in-depth interviews and consumer focus groups.
    • New Product Development Opportunities for Irish Companies in the British Cheese Market

      Cowan, Cathal; Downey, Gerard (Teagasc, 2008-11-01)
      The primary objective of this research was to identify innovative cheese concepts appropriate for UK consumers and suitable for Irish industry to manufacture. It also aimed to identify personal, situational and market factors that influence consumers when purchasing cheese. This research study used existing market literature, in-depth interviews and consumer focus groups.
    • New technologies in the manufacture of low fat meat products

      Allen, Paul; Dreeling, Niamh; Desmond, Eoin; Hughes, Eimear; Mullen, Anne Maria; Troy, Declan J. (Teagasc, 1999-02)
      The objective of this project was to provide a sound scientific basis for the development of low fat meat products. The emphasis was placed on identifying the barriers to producing high quality, low fat meat products and providing a knowledge base for manufacturers to overcome these, rather than actually developing new products. Each partner had specific tasks and worked with traditional products of their country. A wide range of products was thereby studied including comminuted, emulsion, cured and dried fermented, so that the results are widely applicable.
    • New Weapons to Fight Old Enemies: Novel Strategies for the (Bio)control of Bacterial Biofilms in the Food Industry

      Coughlan, Laura M.; Cotter, Paul D.; Hill, Colin; Alvarez-Ordonez, Avelino (Frontiers, 2016-10-18)
      Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc.), although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses the problems associated with bacterial biofilms in the food industry and summarizes the recent strategies explored to inhibit biofilm formation, with special focus on those targeting quorum sensing.
    • Next Generation Sequencing Reveals the Expression of a Unique miRNA Profile in Response to a Gram-Positive Bacterial Infection

      Lawless, Nathan; Foroushani, Amir B. K.; McCabe, Matthew S.; O'Farrelly, Cliona; Lynn, David J. (PLOS, 2013-01-25)
      MicroRNAs (miRNAs) are short, non-coding RNAs, which post-transcriptionally regulate gene expression and are proposed to play a key role in the regulation of innate and adaptive immunity. Here, we report a next generation sequencing (NGS) approach profiling the expression of miRNAs in primary bovine mammary epithelial cells (BMEs) at 1, 2, 4 and 6 hours post-infection with Streptococcus uberis, a causative agent of bovine mastitis. Analysing over 450 million sequencing reads, we found that 20% of the approximately 1,300 currently known bovine miRNAs are expressed in unchallenged BMEs. We also identified the expression of more than 20 potentially novel bovine miRNAs. There is, however, a significant dynamic range in the expression of known miRNAs. The top 10 highly expressed miRNAs account for >80% of all aligned reads, with the remaining miRNAs showing much lower expression. Twenty-one miRNAs were identified as significantly differentially expressed post-infection with S. uberis. Several of these miRNAs have characterised roles in the immune systems of other species. This miRNA response to the Gram-positive S. uberis is markedly different, however, to lipopolysaccharide (LPS) induced miRNA expression. Of 145 miRNAs identified in the literature as being LPS responsive, only 9 were also differentially expressed in response to S. uberis. Computational analysis has also revealed that the predicted target genes of miRNAs, which are down-regulated in BMEs following S. uberis infection, are statistically enriched for roles in innate immunity. This suggests that miRNAs, which potentially act as central regulators of gene expression responses to a Gram-positive bacterial infection, may significantly regulate the sentinel capacity of mammary epithelial cells to mobilise the innate immune system.
    • Nitrofurans : measuring tissue-bound residues in meat

      O'Keeffe, Michael; Connolly, Anne; Nugent, Audrey (Teagasc, 2006-08)
      The aims of this project were to (a) develop a range of screening and confirmatory test methods that might be applied to effectively test for the illicit use of the prohibited nitrofuran antimicrobials, (b) study the persistence of nitrofuran antimicrobials as bound metabolite residues in edible tissues and (c) undertake a pan-European survey of the incidence of nitrofurans in retail pork.
    • Nitrofurans: Measuring Tissue-Bound Residues in Meat

      O’Keeffe, Michael; Conneely, Anne; Nugent, Audrey; Downey, Gerard (Teagasc, 2006-08-01)
      The aims of this project were to (a) develop a range of screening and confirmatory test methods that might be applied to effectively test for the illicit use of the prohibited nitrofuran antimicrobials,(b) study the persistence of nitrofuran antimicrobials as bound metabolite residues inedible tissues and (c) undertake a pan-European survey of the incidence of nitrofurans in retail pork.
    • Nitrogen dynamics in a mature Miscanthus x giganteus crop fertilized with nitrogen over a five year period

      Finnan, John; Burke, B. (Teagasc (Agriculture and Food Development Authority), Ireland, 2014)
      The objective of this study was to investigate N dynamics and response to N fertilization in a mature crop of Miscanthus x giganteus. A crop of Miscanthus x giganteus sown in 1994 was fertilized with five N rates (0, 38, 63, 90 and 125 kg N/ha/year) over a five year period (2008–2012) in Carlow, Ireland. Foliar chlorophyll concentrations were directly related to N fertilization level throughout the study and rose after N applications until July before falling with the onset of N remobilisation. Shoot numbers were unaffected by N fertilization until the final years of the study when they increased with N level. Crop height was unaffected by fertilization in the early years of the study but in the final years of the study, it increased with N level until July after which the effect diminished. There was a small but significant stimulation of harvested biomass yields in autumn (average 15 t/ha) with increasing N fertilization, but there was no effect on harvested yields in spring (average 10.5 t/ha). The N concentration in the rhizome network gradually built up during the course of the study and was proportional to N application. Aboveground biomass N content was also proportional to N application. Nitrogen remobilisation between the October and February harvests was small; abscissed leaves accounted for most of the N loss over this period. The deleterious environmental consequences of N fertilizer may outweigh any potential economic benefits if increases in biomass production are small or non-existent.
    • Nitrogen yield advantage from grass-legume mixtures is robust over a wide range of legume proportions and environmental conditions

      Suter, M.; Connolly, J.; Finn, John A.; Loges, R.; Kirwan, L.; Sebastia, M.T.; Luscher, A. (Wiley, 2015-01-28)
      Current challenges to global food security require sustainable intensification of agriculture through initiatives that include more efficient use of nitrogen (N), increased protein self-sufficiency through home-grown crops, and reduced N losses to the environment. Such challenges were addressed in a continental-scale field experiment conducted over three years, in which the amount of total nitrogen yield (Ntot) and the gain of N yield in mixtures as compared to grass monocultures (Ngainmix) was quantified from four-species grass-legume stands with greatly varying legume proportions. Stands consisted of monocultures and mixtures of two N2 fixing legumes and two non-fixing grasses.The amount of Ntot of mixtures was significantly greater (P ≤ 0.05) than that of grass monocultures at the majority of evaluated sites in all three years. Ntot and thus Ngainmix increased with increasing legume proportion up to one third of legumes. With higher legume percentages, Ntot and Ngainmix did not continue to increase. Thus, across sites and years, mixtures with one third proportion of legumes attained ~95% of the maximum Ntot acquired by any stand and had 57% higher Ntot than grass monocultures.Realized legume proportion in stands and the relative N gain in mixture (Ngainmix/Ntot in mixture) were most severely impaired by minimum site temperature (R = 0.70, P = 0.003 for legume proportion; R = 0.64, P = 0.010 for Ngainmix/Ntot in mixture). Nevertheless, the relative N gain in mixture was not correlated to site productivity (P = 0.500), suggesting that, within climatic restrictions, balanced grass-legume mixtures can benefit from comparable relative gains in N yield across largely differing productivity levels.We conclude that the use of grass-legume mixtures can substantially contribute to resource-efficient agricultural grassland systems over a wide range of productivity levels, implying important savings in N fertilizers and thus greenhouse gas emissions and a considerable potential for climate change mitigation.
    • Nitrous Oxide Emissions

      Hyde, Bernard; Ryan, Mary; Hawkins, M.; Connolly, J.; Carton, Owen T. (Teagasc, 2005-04-01)
      Nitrous oxide (N2O) is one of the three most important greenhouse gases (GHG). Nitrous oxide emissions currently account for approximately one third of GHG emissions from agriculture in Ireland. Emissions of N2O arise naturally from soil sources and from the application of nitrogen (N) in the form of N fertilizers and N in dung and urine deposition by grazing animals at pasture. Nitrous oxide emission measurements were conducted at three different scales. Firstly, a large-scale field experiment was undertaken to compare emission rates from a pasture receiving three different rates of N fertilizer application and to identify the effects of controlling variables over a two-year period. Variation in emission rates was large both within and between years. Two contrasting climatic years were identified. The cooler and wetter conditions in year 1 gave rise to considerably lower emission levels than the warmer and drier year 2. However, in both years, peak emissions were associated with fertilizer N applications coincident with rainfall events in the summer months. A small-plot study was conducted to identify the individual and combined effects of fertilizer, dung and urine applications to grassland. Treatment effects were however, difficult to obtain due to the overriding effects of environmental variables. Thirdly, through the use of a small-scale mini-lysimeter study, the diurnal nature of N2O emission rates was identified for two distinct periods during the year. The occurrence of a diurnal pattern has important implications for the identification of a measurement period during the day which is representative of the true daily flux. The research presented aims to identify the nature and magnitude of N2O emissions and the factors which affect emission rates from a grassland in Ireland. Further work is required to integrate the effects of different soil types and contrasting climatic regimes across soil types on N2O emissions.