Now showing 1 - 10 of 19
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    Improving national mapping of critical source areas of phosphorus and nitrogen losses in Irish agricultural catchments to support policy
    Policymakers, farm advisors and water agencies require up-to-date national maps of critical source areas (CSAs) of nitrogen (N) and phosphorus (P) losses from agricultural land to improve catchment management decisions. The DiffuseTools project aimed to achieve this in Ireland by updating the existing Catchment Characterisation Tool and sub-model NCYCLE_IRL, which predicts environmental losses of N and P from the farm via surface runoff, leaching, denitrification and volatilisation. Updates included (i) using improved national maps of farm-scale source loadings as inputs, (ii) sub-field scale modelling of surface transport risk using soil topographic indices derived from 1 m and 5 m NEXTMap digital elevation models (DEMs), (iii) modelling hydrological disconnectivity from microtopography (HSA Index) and reinfiltration (SCIMAP), (iv) improving the national ditch and stream channel network used by the model by DEM extraction, and (v) using SCIMAP to improve predictions of erosion risk. The improved national source loading maps included mean nationally weighted farm-gate N and P imports (fertilizer, feed and livestock) and balance surpluses (kg/ha) calculated for each stocking rate and soil group (land use potential) category within each sector type (dairy, mixed livestock, suckler cattle, non-suckler cattle, sheep and tillage), using annual Teagasc National Farm Survey data (2008-15). Furthermore, updated national maps of soil P and atmospheric N and P deposition inputs were also used within the national source loading maps to improve model performance. National CSA maps for N and P for each pathway were then produced and evaluated using water quality monitoring data and field observations from the Environmental Protection Agency and Teagasc Agricultural Catchments Programme. These maps will be able to support sustainable intensification by informing farm and catchment management decisions such as where to cost effectively target mitigation measures to reduce environmental losses, where to distribute nutrient surpluses (to non-CSAs in nutrient deficit), and improving functional land management.
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    Variations in travel time for N loading to groundwaters in four case studies in Ireland: Implications for policy makers and regulators
    (Faculy of Agriculture, UCD, 2009-02-01) ; ; ; ;
    Mitigation measures to protect waterbodies must be implemented by 2012 to meet the requirements of the EU Water Framework Directive. The efficacy of these measures will be assessed in 2015. Whilst diffuse N pathways between source and receptor are generally long and complex, EU legislation does not account for differences in hydrological travel time distributions that may result in different water quality response times. The “lag time” between introducing mitigation measures and first improvements in water quality is likely to be different in different catchments; a process that should be considered by policy makers and catchment managers. Many examples of travel time variations have been quoted in the literature but no Irish specific examples are available. Lag times based on initial nutrient breakthrough at four contrasting sites were estimated to a receptor 500 m away from a source. Vertical travel times were estimated using a combination of depth of infiltration calculations based on effective rainfall and subsoil physical parameters and existing hydrological tracer data. Horizontal travel times were estimated using a combination of Darcian linear velocity calculations and existing tracer migration data. Total travel times, assuming no biogeochemical processes, ranged from months to decades between the contrasting sites; the shortest times occurred under thin soil/subsoil on karst limestone and the longest times through thick low permeability soils/subsoils over poorly productive aquifers. Policy makers should consider hydrological lag times when assessing the efficacy of mitigation measures introduced under the Water Framework Directive. This lagtime reflects complete flushing of a particular nutrient from source to receptor. Further research is required to assess the potential mitigation of nitrate through denitrification along the pathway from source to receptor.
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  • Publication
    A controlled evaluation of a prison based sexual offender intervention programme
    The effectiveness of a prison-based cognitive behavioral program designed to modify psychological risk factors associated with sexual offending was evaluated. The Irish Prison Service Sexual Offender Intervention Programme, is a manualized 10-month Cognitive Behaviour Therapy [CBT] program involving three 2-hour group sessions per week, which are facilitated by a team of clinical psychologists and probation officers. Improvements in 38 consecutive referrals to the program were compared with the status of 38 untreated offenders who were similar in marital status, age when they left school, occupational status prior to imprisonment, offence type, presence of previous convictions, and current sentence length. All research participants completed the same assessment protocol, which evaluated psychological factors associated with sexual offending at times equivalent to pre- and postintervention. Compared with the untreated control group, program participants showed statistically significant improvement on some but not all self-report measures of cognitive distortions, empathy, interpersonal skills, self-regulation, and relapse prevention. Motivation to change among the untreated control group was not associated with change in psychological functioning in the absence of the assistance of the treatment program. Implications for sexual offender intervention delivery are considered.
      1028Scopus© Citations 20
  • Publication
    A robust method for the evaluation of prison based sex offender treatment programmes
    (Confénce Permanente Européne de la Probation, 2000-01) ; ; ;
    This paper outlines the approach to evaluating the sex offender treatment programme currently running in the Irish prison system. It begins with an introduction to the scope of the problem of sexual offending as reflected by the extent of the prison population in Ireland who have been convicted of a variety of sexual offences. It then outlines two key points that can be gleaned from several decades of general research on evaluating the effectiveness of psychological treatments while indicating how they have been included in our present research. We also describe the variety of data sources that need to be incorporated into an effective evaluation of prison based sex offender treatment programmes. We conclude with an introduction to some preliminary findings from our on-going research. These finding high-light the return in terms of more reliable information when care is taken in developing a robust method for the evaluation of prison-based sex offender treatment programmes.
  • Publication
    AgriBenchmark: Benchmarking Sustainable Nutrient Management on Irish Farms. EPA Research Report No.274
    (Environmental Protection Agency, 2019-04-18) ; ; ; ;
    AgriBenchmark explored the possibilities for benchmarking of nutrient management performance on Irish farms. Teagasc National Farm Survey (NFS) data (2008–2015; 1446 farms) was used to characterise and explore the potential for improvement of farm nutrient management performance and resultant aspects of environmental and economic sustainability through the derivation of three key performance indicators.
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    Effects of mitigation measures on phosphorus loss across the transfer continuum from soil to water in a monitored dairy grassland catchment
    In many countries with intensive agriculture, water quality is a major issue and phosphorus (P) loss from soils to water is a major pressure. In Ireland, the EU Nitrates Directive Regulations aim to minimise these losses. This study measured the effects of P source management on P transfer across the nutrient transfer continuum from soils to water and subsequent water quality and agronomic impacts in a dairy-dominated, highly stocked and intensively monitored 7.6 km2 grassland catchment with mostly free draining soils over three years. Monitoring included farm P management, surface soil P concentrations, ground- and stream-water concentrations and stream flow. Reduced P source pressure was indicated by: a) lower farm-gate P balances (2.4 kg ha-1 yr-1), higher P use efficiencies (89%) and lower inorganic fertilizer P use (5.2 kg ha-1 yr-1) relative to previous studies, b) almost no P application during the winter to avoid incidental P transfers, and c) decreased proportions of soils with excessive P concentrations (32% to 24%). Over the same period, milk outputs of 14,585 l ha-1 and gross margins of €3,130 ha-1 indicated that production and profitability remained comparable with the top 10% of dairy farmers nationally. Declines in delayed flow and interflow pathway P concentrations during the winter months indicated some response in P delivery in surface water. However, delayed baseflows in the wetter third year resulted in elevated P concentrations and, overall, there were no clear trends in stream biological quality. This suggests that the impact of policy measures may be felt sooner closer to the source end of the nutrient transfer continuum, in soil P concentrations, for example, and a time lag may occur at the other end in P delivery to streams and stream biological quality, with implications for time frames of policy efficacy and policy monitoring.
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    Managing legacy soil phosphorus in grassland soils for agricultural productivity and environmental quality: a review
    Phosphorus (P) is a lithophile element that tends to accumulate in the solid phase at the Earth’s surface and has a low water solubility. As P is a limiting nutrient for plant growth in most terrestrial systems, P in fertilizers has been a major factor underpinning global agricultural production in the 20th and early 21st centuries, including that from grassland. However, P is a costly farm input and it is also a finite mineral resource. Best agronomic practice is to maintain soil P levels at optimum over the medium-to-long term by managing P application and offtake. However, in some cases, soil P levels have been built up in excess of agronomic optimum due to P application driven by organic “waste disposal” or with the intention of building up a “bank” of soil P for future use. This has been associated with P losses to surface waters and impacts on water quality. Legislation, policy and best management practice advice in many countries has attempted to affect these legacy high P soils through a range of measures. In Ireland, for example, the Good Agricultural Practice measures, introduced in 2006 under the Irish Nitrates Action Plan, attempt to impose P deficits on soils with high P. National data shows that P fertilizer use declined by 55% on grassland soils between 2003 and 2008 and would suggest that soils with high soil P levels dropped from 30% in 2007 to 22% in 2011. This paper presents a review of the international literature on legacy excessive P in grassland soils, management practices and policy measures to manage them, and changes in soil P in response to such measures. Consideration is given to both agronomic and environmental concerns. There are a number of factors in grassland production systems, and particularly dairy production systems based on grazed grass, that differ from other agricultural production systems. For example, offtakes are typically lower than in tillage and the recycling of P, either by animal deposition or spreading of manures, gives less control to the farmer. Important questions addressed include: how quickly do grassland soil P levels decline under situations of negative P balance?; what fractions of P control soil P decline?; what grassland management practices are important in determining where and how fast soil P levels decline?; and what scale is appropriate to implement practice change and monitor effects?
  • Publication
    Managing Legacy Soil Phosphorus to Sustain Agriculture and Protect Water Quality
    A central tenet of modern nutrient management planning is the need to maintain soil phosphorus (P) in a range that optimizes crop production and protects water quality. Decades of research have identified the soil test P (STP) critical values needed for economically optimum crop yields, leading to well-established recommendations for efficient use of inorganic and organic P sources as soil amendments. However, in many areas of the USA and other countries, long-term over-application of animal manures and fertilizers has led to soil P accumulations to values that are considerably above agronomic optima and of concern for surface water quality. These soil P accumulations are a legacy of historically inefficient P management and present serious challenges to our efforts today to prevent nonpoint P pollution of surface waters. The fundamental issue identified in most research has been that it can take years, even decades, to decrease soil P values from “excessive” to “optimum”. Thus, even if P inputs to “high P” soils are restricted or eliminated, environmentally significant P losses to water may continue. For example, in Delaware, statewide summaries show ~60% of soils tested have STP values more than twice the critical value (~30 mg P kg-1 , Mehlich 3); in the intensive poultry producing regions, >30% of soils have STP values more than six times the critical value. A recent long-term (11 yr) cropping (corn-soy) study we conducted at two sites with initial Mehlich 3 P values of 98 and 70 mg kg-1 found that ceasing P applications decreased STP by 43% and 27%, with no negative effects on crop yields, providing guidance for emerging strategies for management of “high P” soils. Although similar long-term studies are somewhat rare, we have analyzed the findings of > 25 studies from the US and Europe investigating the relationship between P management, cropping system, and changes in amount and form of P in “high P” soils. Our presentation summarizes the findings of long-term P depletion studies in Delaware and our quantitative analyses of similar studies conducted in settings varying in initial STP, soil type, cropping system, and climate. We present strategies and policies to address the “legacy” P issue in overfertilized soils, toward a goal of sustaining soil P values in ranges optimum for crop production and protection of water quality.
  • Publication
    Analysis of N2O emissions and isotopomers to understand nitrogen cycling associated with multispecies grassland swards at a lysimeter scale
    Nitrous oxide (N2O) is a potent greenhouse gas associated with nitrogen fertiliser inputs to agricultural production systems. Minimising N2O emissions is important to improving the efficiency and sustainability of grassland agriculture. Multispecies grassland swards composed of plants from different functional groups (grasses, legumes, herbs) have been considered as a management strategy to achieve this goal.