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Thomas McCarthy

PhD Scholar

Research Interests

Originally from near Timoleague, Co. Cork, I come from a farming background and have a keen interest in the wider agricultural industry. I completed a BSc (Hons) Degree in Agricultural Science in Waterford Institute of Technology prior to commencing his postgraduate studies. For the placement element of this degree I completed 6 months working on a large scale dairy farm in Canterbury, New Zealand. I have experience working on large scale tillage operations in Norfolk, UK over a number of summers during my third level education.


Current Projects

Thomas’s PhD forms part of the overall FaSTEN project (Farm Sustainability Tools for Efficient Nutrient Management). FaSTEN is funded by DAFM, with Waterford Institute, University College Dublin and Teagasc partners on the project. FaSTEN will develop new knowledge to improve nutrient use efficiency on farms thus reducing potential N losses and emissions to the environment. FaSTEN will build new understanding of soils and key technologies for efficient nutrient management and will identify best knowledge transfer methods for these primary stakeholders. Nutrient management support tools tailored to specific soils, environments and farming systems will be developed to aid farmers and advisory personnel to make profitable and sustainable nutrient management decisions and to benchmark future success. The overall goals of FaSTEN are to develop a decision support tool and nutrient management technologies which harness a new understanding of plant-soil-biodiversity interactions driving nutrient dynamics to deliver soil specific nutrient advice for grassland & arable farms in Ireland. FaSTEN will directly support Food Wise 2025 goals to enhance the sustainability of primary food production systems and will help benchmark nutrient use and environmental standards on farms. Through participation on this project, Thomas will have the opportunity to enhance and develop a range of skills, from laboratory based soil chemical analysis methodologies and field-based experimental expertise, to academic writing and statistical analysis using computer software.

Project Title

‘Optimising potassium fertilisation strategies for enhanced grassland nitrogen use efficiency (NUE) and decreasing greenhouse gas emissions’

Project Overview

The intensification of Irish grassland based dairy production systems over recent years in the era post milk quota abolishment has given rise to a number of concerns environmentally. At the centre of these environmental implications is the heavy reliance on chemical nitrogen fertiliser inputs in the sector in order to achieve high levels of grassland production and consequently maintain milk production. Nitrogen fertilisers, while essential to maintaining current grassland dry matter production levels, are often linked to contributing to the deteriorating quality of waterbodies nationally, as well as contributing to greenhouse gas emissions such as nitrous oxide and ammonia emissions. Reducing reliance on chemical nitrogen fertilisers while simultaneously maintaining current levels of forage production, and thereby enhancing the future sustainability of the Irish dairy sector is seen as one of the biggest challenges facing both the sector and researchers alike.

Thomas is investigating the role of other soil macronutrients, in particular potassium and the agronomic interaction between this nutrient and nitrogen. It has long been established that the two nutrients are intrinsically linked agronomically for both uptake and utilisation within the plant, therefore potassium is associated with increasing the use efficiency of applied nitrogen, and Thomas’s experimental work assesses this in a simulated grazing grassland sward trial scenario. Furthermore, clover species are highly responsive to adequate potassium supply and soil potassium fertility, with the persistence of clover species in the grassland sward being associated with the degree of sward nitrogen supply by way of biological N fixation. The primary aim of Thomas’s PhD is to investigate avenues towards increasing grassland nitrogen use efficiency through these two fundamental pathways, while also looking at the effect of potassium on sward quality, yield and composition as well as losses by leaching. Thomas is also researching the effect of soil type on potassium dynamics, in order to increase understanding of potassium in varying soil types and to update recommended advice relative to potassium application to grassland.


David Wall, Dr. Patrick Forrestal & Dr James Humphreys (Teagasc)

Imelda Casey, (Waterford Institute of Technology)


Department of Agriculture, Food & Marine


  • 2020  -  BSc (Hons) Degree in Agricultural Science