Browsing by Author "Williams, Adrian"
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Item Open Access An anticipatory life cycle assessment of the use of biochar from sugarcane residues as a greenhouse gas removal technology(Elsevier, 2021-06-02) Lefebvre, David; Williams, Adrian; Kirk, Guy J. D.; Meersmans, Jeroen; Sohi, Saran; Goglio, Pietro; Smith, PeteGreenhouse gas removal technologies are needed to reach the targets of the UNFCCC Paris Agreement. Among existing technologies, the use of biochar is considered promising, particularly biochar derived from the large quantities of sugarcane residues available in South America and elsewhere. However, the net greenhouse gas removal potential of sugarcane biochar has not been assessed hitherto. We use a scenario-based anticipatory life cycle assessment to investigate the emissions associated with a change from the combustion of sugarcane residues in a combined heat and power plant to the pyrolysis of these residues for biochar production and field application in São Paulo State, Brazil. We define scenarios based on different mean marginal electricity production and biochar production share. The results indicate that emissions from covering the electricity deficit generated by partial combustion of biomass during biochar production is the main emitting process. Overall, the processes associated with biochar production lower the net greenhouse gas benefits of the biochar by around 25%. Our analysis suggests that allocating 100% of the available sugarcane residues to biochar production could sequester 6.3 ± 0.5 t CO2eq ha−1 yr−1 of sugarcane in São Paulo State. Scaled up to the entire State, the practice could lead to the removal of 23% of the total amount of GHGs emitted by the State in 2016.Item Open Access Assessing the potential of soil carbonation and enhanced weathering through Life Cycle Assessment: a case study for Sao Paulo State, Brazil(Elsevier, 2019-06-11) Lefebvre, David; Goglio, Pietro; Williams, Adrian; Manning, David A. C.; de Azevedo, Antonio Carlos; Bergmann, Magda; Meersmans, Jeroen; Smith, PeteEnhanced silicate rock weathering for long-term carbon dioxide sequestration has considerable potential, but depends on the availability of suitable rocks coupled with proximity to suitable locations for field application. In this paper, we investigate the established mining industry that extracts basaltic rocks for construction from the Paraná Basin, Sao Paulo State, Brazil. Through a Life Cycle Assessment, we determine the balance of carbon dioxide emissions involved in the use of this material, the relative contribution of soil carbonation and enhanced weathering, and the potential carbon dioxide removal of Sao Paulo agricultural land through enhanced weathering of basalt rock. Our results show that enhanced weathering and carbonation respectively emit around 75 and 135 kg carbon dioxide equivalent per tonne of carbon dioxide equivalent removed (considering a quarry to field distance of 65 km). We underline transportation as the principal process negatively affecting the practice and uncover a limiting road travel distance from the quarry to the field of 540 ± 65 km for carbonation and 990 ± 116 km for enhanced weathering, above which the emissions offset the potential capture. Regarding Sao Paulo State, the application of crushed basalt at 1 t/ha to all of the State's 12 million hectares of agricultural land could capture around 1.3 to 2.4 Mt carbon dioxide equivalent through carbonation and enhanced weathering, respectively. This study suggests a lower sequestration estimate than previous studies and emphasizes the need to consider all process stages through a Life Cycle Assessment methodology, to provide more reliable estimates of the sequestration potential of greenhouse gas removal technologies.Item Open Access Characterising the biophysical, economic and social impacts of soil carbon sequestration as a greenhouse gas removal technology(Wiley, 2019-09-18) Sykes, Alasdair J.; Macleod, Michael; Eory, Vera; Rees, Robert M.; Payen, Florian; Myrgiotis, Vasilis; Williams, Mathew; Sohi, Saran; Hillier, Jon; Moran, Dominic; Manning, David A. C.; Goglio, Pietro; Seghetta, Michele; Williams, Adrian; Harris, Jim A.; Dondini, Marta; Walton, Jack; House, Joanna; Smith, PeteTo limit warming to well below 2°C, most scenario projections rely on greenhouse gas removal technologies (GGRTs); one such GGRT uses soil carbon sequestration (SCS) in agricultural land. In addition to their role in mitigating climate change, SCS practices play a role in delivering agroecosystem resilience, climate change adaptability, and food security. Environmental heterogeneity and differences in agricultural practices challenge the practical implementation of SCS, and our analysis addresses the associated knowledge gap. Previous assessments have focused on global potentials, but there is a need among policy makers to operationalise SCS. Here, we assess a range of practices already proposed to deliver SCS, and distil these into a subset of specific measures. We provide a multi‐disciplinary summary of the barriers and potential incentives toward practical implementation of these measures. First, we identify specific practices with potential for both a positive impact on SCS at farm level, and an uptake rate compatible with global impact. These focus on: a. optimising crop primary productivity (e.g. nutrient optimisation, pH management, irrigation) b. reducing soil disturbance and managing soil physical properties (e.g. improved rotations, minimum till) c. minimising deliberate removal of C or lateral transport via erosion processes (e.g. support measures, bare fallow reduction) d. addition of C produced outside the system (e.g. organic manure amendments, biochar addition) e. provision of additional C inputs within the cropping system (e.g. agroforestry, cover cropping) We then consider economic and non‐cost barriers and incentives for land managers implementing these measures, along with the potential externalised impacts of implementation. This offers a framework and reference point for holistic assessment of the impacts of SCS. Finally, we summarise and discuss the ability of extant scientific approaches to quantify the technical potential and externalities of SCS measures, and the barriers and incentives to their implementation in global agricultural systems.Item Open Access Determining the carbon footprint of a National Trust country estate(Cranfield University, 2009-09) Slater, Dora; Burgess, Paul J.; Williams, AdrianThe UK Government aims to reduce greenhouse gas emissions by 80 % by 2050 against a 1990 baseline. Agriculture makes up around 7 % of UK emissions and the industry is under pressure to meet these targets (and to produce more food). To achieve reductions it is necessary to be able to calculate emissions. This study looks at methods to calculate the carbon footprint of a National Trust estate with livestock, arable farming and a stately home. Methods explored include greenhouse gas inventories, life cycle analysis and carbon calculators. A carbon calculator designed for farms was selected (the CALM Calculator) and applied to Wimpole Hall, Cambridgeshire. Key greenhouse gas sources were identified and estate activity data gathered to calculate the footprint. A comparison was made between current arable practices and proposed organic methods. Emissions from estate energy and water consumption were also included. The arable non-organic farm emitted 1018 tCO2e, 73 % due to N2O emissions from nitrogen fertilizers. The livestock farm emitted 686 tCO2e, 44 % from cattle. Estate emissions from electricity, heating oil and water supply were 303 tCO2e. The total estate footprint was calculated as 2007 tCO2e. A change to organic arable methods was predicted to deliver an estate footprint of 1361 tCO2e but yields will be less (organic wheat is said to yield only 68 % of non-organic). The removal potential of conversion of areas of arable to grassland (41 tCO2e) and particularly of farm woodland (1430 tCO2e) was noticeable. Combined these can offset 73 % of total estate emissions using non-organic arable methods and 103 % of total estate emissions using proposed organic arable methods. Shortcomings of the method are identified along with the high level of uncertainty connected to the results. The issue of reduced yield expected under organic arable cultivation is highlighted and the implications of balancing reduced emissions with maintaining food production are explored.Item Open Access Development of Crop.LCA, an adaptable screening life cycle assessment tool for agricultural systems: a Canadian scenario assessment(Elsevier, 2017-06-22) Goglio, Pietro; Smith, Ward N.; Worth, Devon E.; Grant, Brian B.; Desjardins, Raymond L.; Chen, Wen; Tenuta, Mario; McConkey, Brian G.; Williams, Adrian; Burgess, PaulThere is an increasing demand for sustainable agricultural production as part of the transition towards a globally sustainable economy. To quantify impacts of agricultural systems on the environment, life cycle assessment (LCA) is ideal because of its holistic approach. Many tools have been developed to conduct LCAs in agriculture, but they are not publicly available, not open-source, and have a limited scope. Here, a new adaptable open-source tool (Crop.LCA) for carrying out LCA of cropping systems is presented and tested in an evaluation study with a scenario assessment of 4 cropping systems using an agroecosystem model (DNDC) to predict soil GHG emissions. The functional units used are hectares (ha) of land and gigajoules (GJ) of harvested energy output, and 4 impact categories were evaluated: cumulative energy demand (CED), 100-year global warming potential (GWP), eutrophication and acidification potential. DNDC was used to simulate 28 years of cropping system dynamics, and the results were used as input in Crop.LCA. Data were aggregated for each 4-year rotation and statistically analyzed. Introduction of legumes into the cropping system reduced CED by 6%, GWP by 23%, and acidification by 19% per ha. These results highlight the ability of Crop.LCA to capture cropping system characteristics in LCA, and the tool constitutes a step forward in increasing the accuracy of LCA of cropping systems as required for bio-economy system assessments. Furthermore, the tool is open-source, highly transparent and has the necessary flexibility to assess agricultural systems.Item Open Access Environmental resource use by agricultural and horticultural commodities - Defra project report IS0205(Cranfield University, 2019-02-05 09:24) Williams, Adrian; Audsley, Eric; Sandars, DanielUnderlying models used in the report: "Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities." Defra project report IS0205 by the Natural Resource Management Institute, Cranfield University, August 2006. The final report and executive summary are available from the defra site at the link provided.Item Open Access Fresh Meat Resource Maps(2011-06-01T00:00:00Z) Whitehead, Peter; Palmer, Martin; Mena, Carlos; Williams, Adrian; Walsh, ChristineItem Open Access The impact of changing food choices on the blue water scarcity footprint and greenhouse gas emissions of the British diet: the example of potato, pasta and rice(Elsevier, 2015-09) Hess, Tim; Chatterton, Julia; Daccache, Andre; Williams, AdrianFood production is a major contributor to a country's environmental burden. However, the burdens associated with individual foods vary significantly due to differing agricultural systems and locations, post-harvest storage, manufacturing and transport requirements. Dietary choices can therefore have a significant impact on the overall burdens associated with food consumption. Previous studies have generally considered changes in the proportion of animal-based foods in the diet or changes to a vegetarian, or a vegan diet. Using a life cycle assessment approach and data from published sources supplemented by original analysis, we estimated the blue water scarcity footprint and greenhouse gas emissions associated with the production, manufacture and distribution of three popular starchy carbohydrate foods as consumed in the United Kingdom – British fresh potatoes, Italian dried pasta and Indian dried basmati rice. Although similar to pasta in terms of greenhouse gas emissions per unit carbohydrate, when considered on the basis of typical portion size, potatoes have lower greenhouse gas emissions than pasta or basmati and the blue water scarcity footprint of basmati is two orders of magnitude greater than potatoes or pasta. The increasing preference for pasta and rice and reduction in household purchases of fresh potatoes in the United Kingdom over the period 1981–2010 has resulted in an increase in blue water scarcity footprint and a transfer of burdens from the United Kingdom to Italy and India, however the increased greenhouse gas emissions associated with rice and pasta has been, more or less, compensated by a reduction in emissions associated with purchases of potatoes. This paper has shown that dietary choices within food groups (in this case starchy carbohydrates) have a significant impact on an individual's contribution to greenhouse gas emissions and blue water scarcity footprint. The life cycle assessment approach is useful for understanding where the impacts of dietary choices occur and can inform the supply chain about where efforts should be targeted to reduce those impacts.Item Open Access The impacts of a large-scale conversion to organic agriculture in England and Wales(2017-07) Smith, Laurence G.; Williams, Adrian; Kirk, Guy; Pearce, BruceWith the need to identify sustainable modes of food production for growing populations there has been a growing interest in the potential of organic farming. Although evidence suggests that organic systems can produce food in an environmentally efficient manner, the impacts of a widespread conversion to organic management are still uncertain. The research presented aimed to address this knowledge gap by completing a comprehensive and robust assessment of the food production, fossil energy-use and greenhouse gas impacts associated with a 100% conversion to organic farming in England and Wales. Firstly a structured literature review was carried out to determine the relative fossil-energy efficiency of organic systems. The sustainability of typical organic crop rotations was then assessed using a simulation model of crop-soil N dynamics. Land-use and production scenarios under 100% organic management were assessed through the development and application of a large-scale linear programming model that estimates levels of production under biophysical constraints, e.g. N supplies from biological fixation by legumes. A life-cycle assessment-based model was then applied to explore the extent to which a 100% conversion to organic farming could lead to improvements in greenhouse gas mitigation and fossil energy efficiency. The environmental assessment approach allowed for processes inside and outside of the immediate boundaries of the production systems to be assessed, with the question “what is affected by the change in levels of production?” asked throughout the process. The results revealed that whilst some organic systems offer improved performance in non-renewable resource use efficiency, a widespread conversion would result in a substantial decrease in domestic food production. Total food output expressed over five major food groups fell to 64% of a non-organic baseline. An increase in food imports would therefore be required to meet demand. From a greenhouse gas perspective, a 100% conversion to organic farming in England and Wales could lead to 6% decrease in the impacts of food production. The greenhouse gas mitigation potential of organic farming is strongly related to the use of clover and other legumes in place of manufactured N and lower concentrate feed rates in livestock production. Where the additional-land required under an organic scenario is newly cultivated, it is likely that any greenhouse gas benefit obtained would be offset. Total greenhouse gas emissions increased by an average of 28%, compared to a non-organic baseline, when the land use change impacts associated with increased food imports were included. When the soil carbon sequestration benefits obtained through organic farming are also included the net difference between the two production systems is lessened, however a fundamental question remains concerning the availability of overseas land (land use requirements under organic management increased by 29-47% depending on the scenario). Reducing the area of fertility-building ley within organic rotations is likely to improve productivities and reduce land-use requirements within organic farming systems. Improving crop cultivation practices, more effective cover-cropping and improved biological N-fixation could also help to improve N efficiency and productivity within organic systems. Changes to international organic standards in some areas may also improve the environmental sustainability of the sector, e.g. by allowing recycling of P from sewage treatment. Overall the research showed that whilst the adoption of organic farming can lead to improvements in environmental performance, a widespread conversion would need to be accompanied by substantial changes in diet and/or typical organic practices to become feasible from the perspectives of environmental impact and total food production.Item Open Access Life cycle assessment of land-based greenhouse gas removal technologies.(2021-06) Lefebvre, David; Williams, Adrian; Kirk, GuyGreenhouse gas removal technologies (GGRT) are needed to meet the UNFCCC aim to limit the global average temperature increase to 2°C above pre-industrial levels. GGRTs vary in carbon sequestration potential, readiness level, scalability, cost, required surrounding environment and related environmental and social effects. Quantifying these components in every context is critical to ensure maximum greenhouse gas removal efficiency while minimising negative effects. In this thesis I use life cycle assessment (LCA) to assess the carbon sequestration potential of three GGRTs: enhanced weathering, biochar and reforestation. I use case studies in São Paulo, Brazil for biochar and enhanced weathering, and in the Peruvian Amazon for reforestation. In addition, I use LCA to identify the most important processes in each system and to determine context-specific limits that switch the systems from net GHG sequestration to net GHG emission. Overall, this work promotes the use of LCA to consider GGRTs in their entirety and predict their context-specific carbon capture potential, along with their limitations and potential caveats to guide both the science and policy communities. This thesis was made possible thanks to funding through the SOILS-R-GGREAT (NE/P019498/1) project of the greenhouse gas removal (GGR) program. The GGR program is financed by the UK Natural Environment Research Council (NERC), Engineering and Physical Science Research Council (EPSRC), Economic and Social Science Research Council (ESRC) and the UK department for Business, Energy and Industrial Strategy (BEIS).Item Open Access Modelling and valuing the environmental impacts of arable, forestry and agroforestry systems: a case study(2017-10-03) García de Jalón, Silvestre; Graves, Anil; Palma, João H. N.; Williams, Adrian; Upson, Matt; Burgess, Paul J.The use of land for intensive arable production in Europe is associated with a range of externalities that typically impose costs on third parties. The introduction of trees in arable systems can potentially be used to reduce these costs. This paper assesses the profitability and environmental externalities of a silvoarable agroforestry system, and compares this with the profitability and environmental externalities from an arable system and a forestry system. A silvoarable experimental plot of poplar trees planted in 1992 in Bedfordshire, Eastern England, was used as a case study. The Yield-SAFE model was used to simulate the growth and yields of the silvoarable, arable, and forestry land uses along with the associated environmental externalities, including carbon sequestration, greenhouse gas emissions, nitrogen and phosphorus surplus, and soil erosion losses by water. The Farm-SAFE model was then used to quantify the monetary value of these effects. The study assesses both the financial profitability from a farmer perspective and the economic benefit from a societal perspective. The arable option was the most financially profitable system followed by the silvoarable system and forestry. However, when the environmental externalities were included, silvoarable agroforestry provided the greatest benefit. This suggests that the appropriate integration of trees in arable land can provide greater well-being benefits to society overall, than arable farming without trees, or forestry systems on their own.Item Open Access Modelling the potential for soil carbon sequestration using biochar from sugarcane residues in Brazil(Nature Publishing Group / Nature Research / Springer Nature, 2020-11-10) Lefebvre, David; Williams, Adrian; Meersmans, Jeroen; Kirk, Guy J. D.; Sohi, Saran; Goglio, Pietro; Smith, PeteSugarcane (Saccharum officinarum L.) cultivation leaves behind around 20 t ha−1 of biomass residue after harvest and processing. We investigated the potential for sequestering carbon (C) in soil with these residues by partially converting them into biochar (recalcitrant carbon-rich material). First, we modified the RothC model to allow changes in soil C arising from additions of sugarcane-derived biochar. Second, we evaluated the modified model against published field data, and found satisfactory agreement between observed and predicted soil C accumulation. Third, we used the model to explore the potential for soil C sequestration with sugarcane biochar in São Paulo State, Brazil. The results show a potential increase in soil C stocks by 2.35 ± 0.4 t C ha−1 year−1 in sugarcane fields across the State at application rates of 4.2 t biochar ha−1 year−1. Scaling to the total sugarcane area of the State, this would be 50 Mt of CO2 equivalent year−1, which is 31% of the CO2 equivalent emissions attributed to the State in 2016. Future research should (a) further validate the model with field experiments; (b) make a full life cycle assessment of the potential for greenhouse gas mitigation, including additional effects of biochar applications on greenhouse gas balances.Item Open Access On-farm greenhouse gas emissions associated with the cultivation of two new bioenergy crops in the UK(Elsevier, 2022-11-28) Cumplido-Marin, Laura; Graves, Anil R.; Burgess, Paul J.; Williams, AdrianBefore using novel energy crops to produce bioenergy, feasibility studies should be completed to determine their effect on net greenhouse gas emissions. The current study developed a model to study the greenhouse gas emissions associated with the cultivation of two novel bioenergy crops: Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L., using Intergovernmental Panel on Climate Change (IPCC) guidelines. The establishment and cultivation of Sida hermaphrodita and Silphium perfoliatum were compared with an arable rotation, short rotation coppice (SRC) and Miscanthus. Under the assumptions specified in the current study, including annual fertilisation and a high root: shoot ratio for Sida, the cultivation of Sida hermaphrodita and Silphium perfoliatum resulted in a mean net emission of 3.0 Mg CO2eq ha−1y−1 and mean net sequestration of 0.6 Mg CO2eq ha−1y−1 respectively over a 16 year rotation. This compared to predicted mean net emissions of 4.2 Mg CO2eq ha−1y−1 for an arable rotation, and intermediate values for the SRC and Miscanthus crop (1.0 and 2.2 Mg CO2eq ha− 1y− 1, respectively).Item Open Access The quantification and improvement of vehicle support capacity in a weak soil(Cranfield University, 2004-04-13) Shorten, David; Godwin, R. J.; Williams, AdrianThe aim of this study was to improve the characteristics of surfacing methods/materials for the temporary support of military vehicles travelling over weak soils. Both off road travel and poor existing road networks provide problems for vehicle mobility in military operations under these conditions. Conventional road construction materials are often in short supply and engineered solutions such as Class 30 & 70 Trackway are expensive and form a significant logistical burden on the military supply chain. In this situation the use of locally available alternative materials in the construction of temporary roads can reduce the time taken to get routes operational, allowing the tempo of operations to be maintained. The work reported focussed on two main areas of work, namely: i) The development of a technique for assessing the soil support capacity in the form of a flat plate (45 x 30 mm) penetrometer to aid the decision/ planning process when faced with poor soil support, and ii) the evaluation of the relative performance of a range of alternative materials/ techniques in laboratory conditions at 1/5'*’ scale and full size. The results of load-sinkage tests of a family of plate sizes indicate that by normalising the data with respect to plate width a common relationship existed for all plate sizes in each of the soil conditions investigated. From this, a technique was developed to estimate the load support of a plate with dimensions equivalent to the contact patch of a tyre using load-sinkage data from a small plate penetrometer, allowing estimates of: i) sinkage or rut depth expected from a vehicle load, and ii) the load at a sinkage equivalent to the tyre contact patch width, a point at which the vehicles were assumed to be immobilised. Comparison between the rut depth of a single pass of a towed wheel and the sinkage from plate tests (45 x 30 mm) were within 20% in a sandy loam soil of bulk unit weight 12.2 and 13.4 kN/m^. Load sinkage predictions of a 450 x 300 mm plate from a small plate penetrometer were within 35% in a sandy loam soil with bulk unit weights of 11.7 and 13.4 kN/m^. Load sinkage predictions for a very weak sandy loam (11.3 kN/m^) and loose sand (15.1 - 16.1 kN/m^) soils tended to be significantly underestimated especially at large plate sizes, mainly due to scaling effects in these David Shorten, 2004 Cranfield University, Silsoe 11 situations as well as the significant re-arranging occurring in weak soil subjected to loaded plates. Improvements in accuracy to 25-35% could be made in these conditions by increasing the size of the plate penetrometer to 90 x 60 mm and utilising a similitude scaling technique. Materials/techniques for improving soil support have been classified into 4 categories, namely: sheet materials, rigid members, aggregate materials and stabilisation techniques. The use of sheet materials, in this case a Hessian geotextile, proved effective in improving the in situ soil support; it was possible to optimise the width and placement depth to increase load support by a factor of 1.8. A folded confinement technique encapsulating a soil fill was developed further, resulting in a 3-fold improvement in the load support. Tied corduroy techniques performed best with a 5- fold improvement in load support. Factors such as the rope tension between members were found to be important to produce a stable road surface. The performance of aggregates increased with larger aggregate sizes. Increasing the thickness of the aggregate layer enhanced load support in stone aggregate, while in wood and rubber aggregate performance is affected by the initial compressibility of the material. Aggregate mixed with a sand filler proved effective at reducing the compressibility of the alternative aggregate materials, thus enhancing performance. The use of alternative materials in military operations has been identified as very scenario dependent. Alternative materials have been shown to increase the load support capability of weak soils. Although alternative materials are unlikely to be used as a substitute in conventional road construction, their use on short sections of roadway is feasible. Situations where conventional aggregate materials are limited and an alternative aggregate can be obtained locally would offer a solution enabling military operations to continue. Significant quantities of materials are required to construct even small sections of roadway in weak soil conditions; success is very much dependent on the amount of material locally available, for example a 100 m section may require 180 m^ of timber aggregate approximately equal to 0.25 ha of a 45 yr Sitka Spruce plantation. This information will be of use to aid decisions made by the Combat Engineer and has been recommended by the MOD for inclusion in the Military Engineering Volume.Item Open Access Source data for a study exploring production impacts of a 100% organic conversion in England and Wales(Cranfield University, 2018-05-13 21:34) Smith, Laurence; Jones, Philip; Kirk, Guy; Pearce, Bruce; Williams, AdrianUnderlying data for ‘Modelling the production impacts of a widespread conversion to organic agriculture in England and Wales’ by L.G. Smith et al. (2018). We develop and apply a bespoke model, the Optimal Land Use Model (OLUM) to estimate levels of production from agriculture in England and Wales under organic management . Outputs under a range of scenarios are compared to the real-world distribution of conventional production in 2010.Item Open Access The water footprint of Irish meat and dairy products(Cranfield University, 2012-02-29) Hess, Tim M.; Chatterton, Julia; Williams, AdrianThe water consumption of a range of dairy and beef production systems was estimated for four locations in Ireland using the Cranfield Life Cycle Assessment (LCA) systems model. This included direct water consumption (for drinking, washing, cleaning, etc.) as well as virtual water in the diet (that is, water that had been used to grow grass and concentrate feedstuffs). This was partitioned into “blue” water that is abstracted from rivers or groundwater, or taken from mains water supplies, and “green” water that is rain water used by growing plants at the place where the rain falls. In general, intensive systems have a lower water consumption per unit of output than extensive systems as the higher water consumption per head is offset by high output. The water consumption of dairy-beef systems is lower than for suckler beef because most of the water use by the dairy cow is allocated to the dairy system, whereas for suckler systems, the water use of the suckler cow is included for the first year. It is clear that the vast majority of the total water consumption for all the systems studied is green water. It can be argued that green water use has negligible environmental impact as it has a low, or negligible opportunity cost. The rain water consumed by growing grass or feed crops could only be used for growing alternative vegetation, that is, it could not be used to substitute for water for domestic or industrial consumption for example. Therefore, there is no water benefit in saving green water. The blue water consumption is very small for both milk and beef under all systems. Drinking water accounts for almost half of the blue water used by dairy systems, and almost all of that consumed by beef systems. Therefore, technologies that reduce the wastage / leakage in on farm drinking water systems can reduce the overall water consumption. For dairy systems the remainder of the blue water consumption is associated with milk cooling and cleaning of the milking parlour and yards. The amount of blue water associated with growing feed is trivial. For dairy, twice as much blue water is consumed in the processing of milk compared to the livestock and feed systems. For dairy-beef and suckler beef, blue water consumption on the farm 2.5 and 7.4 times as much as used in the processing stage respectively. Most water use on Irish livestock farms is from groundwater (90%) and mains water (10%). Generally, widespread abstraction pressures on groundwater are not significant in Ireland and the impact of water use would be expected to be small, however, there are some localised cases where abstraction pressures are impacting on groundwater levels (EPA, 2008). This highlights the very local scale of hydrological impacts and suggests that even though the average water consumption of Irish beef and dairy production is very small, in certain places it may be contributing to depletion of groundwater resources and water conservation may be encouraged. The Water Stress Index can be used to normalise the blue water consumption and to derive an index of water equivalent (H2Oe) that reflects both the volume of blue water consumed and relative stress on water in the producing region. For dairy systems, the normalised water footprint of milk production (at the farm gate) ranges from 0.12 litres H2Oe/litre fat and protein corrected milk (FPCM) for high yielding autumn calving systems in the south of Ireland to 0.17 for low-yielding, spring calving systems in the south-east. For beef systems, the normalised water footprint of milk production (at the farm gate) ranges from 0.24 litres H2Oe/kg for extensive dairy beef systems in the south of Ireland to 0.98 for autumn calving, extensive finishing systems in the south-east. These figures are very low compared to other livestock producing regions.