Agriculture and Food Science Theses

Stem growth, biomass partitioning and wood properties vary between genotypes, so information on how these traits interact with each other and are influenced by environment conditions is required. To this end, above and below ground growth, morphology and wood properties of a selection of elite juvenile Sitka spruce (Picea sitchensis (Bong.) Carr.) clones grown in Ireland were investigated in this study.The effects of intra- and inter-clonal competition were assessed for up to three years after planting in a field trial containing ramets (i.e. an independent individual of a clone produced by tissue cultures) planted in multi-clone (mixed) and mono-clonal (pure) plots. Stem height, diameter and biomass partitioning were found to be significant reduced for some clones when planted in mixed plots than in pure plots. Height and diameter results were more heterogeneous and competition was more asymmetrical in mixed than in pure plots. Plot type significantly increased fine root surface area in mixed plots and fine root length in pure plots for two fine root diameter classes for some clones. However, intra- or inter-clonal competition did not result in any significant changes in specific root length, specific root area, root:shoot ratio or root chemical composition.Increased height growth in the most vigorous clone was associated with significantly thinner cell walls and wider tracheids than the less vigorous clones, reducing mean wood density and other indicators of wood quality. The width of the early- and latewood band in each annual ring was a more important determinant of juvenile wood quality than the characteristics of the cells within each band. Radial tracheid width was significantly and positively correlated with ring width and stem height but was negatively correlated with wood density. Wood properties differed greatly between clones, suggesting that there is potential to improve juvenile wood properties through selective breeding while achieving modest gains in height.The results of this study demonstrated that competition-induced morphological changes did not occur either above or below ground for the majority of the studied Sitka spruce clones, but greater size heterogeneity was observed for clones planted in mixed plots than in pure stands. Additionally, the most vigorous clones had less-desirable wood properties than the less vigorous clones, which would reduce their wood quality.

Cadmium (Cd) is a heavy metal found in soils all around the globe. This toxic metal accumulates in crops grown for consumption and is capable of causing harm to human health if consumed in high enough concentrations. There are several regions in Europe and across the globe with elevated levels of soil cadmium from a variety of sources, and the source of this cadmium determines the type of mitigation strategies needed to decrease levels of Cd in the soil. The source may be anthropogenic from use of phosphatic fertilizers or industrial contamination or geogenic from the weathering of soil and bedrock. There are maximum permitted levels of cadmium allowed in produce, as set by the European Union. Currently, there are discussions taking place in regard to lowering those maximum levels, making compliance a certain risk amongst growers in one of the most productive horticultural areas of Ireland. A mixture of methods was used to examine knowledge and attitudes of potato growers and agronomists in counties Meath, Dublin, and Kildare in Ireland where there are established elevated levels of available soil cadmium. The overall purpose of this study was to future proof the potato industry against this risk and provide insight into the effectiveness of advisory and knowledge transfer (KT) communication on farmer attitudes, knowledge, and intention to implement, particularly when dealing with an uncertain and unwelcome risk. Thirty-nine (39) growers and seven agronomists took part in one-on-one interviews and surveys regarding awareness of heavy metal contamination and intentions to mitigate. Themes from the interviews were established and analyzed in NVIVO, while quantitative statistical analysis was performed for the 39 grower surveys and seven agronomist surveys in SPSS. Qualitative analysis of the 39 one-on-one grower interviews and quantitative analysis of the 39 grower surveys revealed a very low level of awareness around the Irish cadmium issue but a high level of intention to mitigate. Qualitative analysis of the seven agronomists and quantitative analysis of the seven agronomist surveys revealed a very high level of awareness and concern in regard to the cadmium issue with a low level of knowledge on possible mitigation strategies and low rate of advising clients with regard to same. This project has components dealing with themes of uncertainty, negative messages, and many others that are applicable to not only tillage but also dairy and drystock sectors. This research offers insights into understanding the best practice of communicating unpalatable messages to farmers in a way that allows them to see the best possible outcomes so that the message is at least somewhat welcomed, wanted, and accepted by the farmer.

Digital technologies are transforming the everyday lives and practices of many people across the globe, including how they operate in their working lives. This too has even translated to the practices of farm advisors and farm advisory services in how they deliver advice to their farmer clients. Digital skills are becoming an essential element of modern advisory practices and management as a growing amount of digital technologies and tools become available. While there is a wide variety of digital tools available to farm advisors, most of these are underutilised. As agriculture changes through digital disruption, farmers should have the appropriate support to allow them to adopt such technologies. Farm advisors play an essential role in providing this support and in motivating farmers to adopt digital tools. They are central in helping to bridge the digital divide experienced by farmers in adapting digital technologies; however, this digital divide is also apparent in farm advisory services. Therefore, focus must be given, first and foremost, to ensure that the farm advisory community are equipped to address this challenge and provide ongoing support to their clients. Hence, this research focused on identifying the main challenges and trends to embedding Digital Advisory Tools and Services (DATS) in farm advisory. This research is based on two multi-actor workshops and an online survey completed by 212 public (Teagasc) farm advisors. The workshops involved a broad group of actors who had a vested interest in and/or an in-depth experience in embedding DATS in Irish agriculture. Some of the key themes that emerged in these workshops were then incorporated as constructs into a modified behavioural model survey along with the main constructs from the Theory of Planned Behaviour (Ajzen, 1991) and The Technology Acceptance Model (Davis, 1989). The findings of the study uncovered some of the important characteristics of DATS to make them attractive to farm advisors to aid their uptake such as being simple, easy to use, accessible and trustworthy. Accessibility and the interoperability of DATS in being able to operate and exchange data was also seen as key. The study also uncovered factors that influence farm advisors’ behavioural intention and attitude towards the use of DATS. Attitude, perceived behavioural control and perceived usefulness were found to be important determinants of a farm advisors’ Behavioural intention to use DATS. Likewise perceived usefulness was found to positively influence farm advisors’ attitude towards DATS. Ultimately the study recognised that digital technologies are integral to farm advisors meeting the challenges of an increasingly complex advisory system and it is important that advisors have access to a continuous training programme to ensure they have a positive attitude and a high degree of self-confidence to use DATS in their work.

Commonages represent ~7% of Agricultural land in Ireland. As predominantly high nature value areas these are of particular interest for preservation and restoration works to encourage biodiversity. However as commonly managed areas this presents a management issue as all parties commonly farming these lands need to work collectively together to make a positive environmental impact. The SUAS project brings together groups of farmers together on these commonages to discuss and address the issues as per each individual commonage. Together proposals are made to address the issues and produce results. In the pursuit of this collective action there is a potential hurdle in achieving harmonised collaboration due to the personal and cultural differences in participants. This study draws on the experiences of SUAS in order to determine key factors and lessons which aid and enhance the collaboration process so that future collaborative projects of a similar nature in Ireland or further afield can share in these lessons. As discovered from the study, key aspects to delivering successful collaboration include: (1) Farmer involvement in all aspects of the project from the beginning. (2) The input of an external facilitator and project manager with distinctly separate roles. (3) Project Manager traits including open and effective communication skills, facilitation and conflict resolution skills, locally knowledgeable, local to the vicinity, an effective and fair leader. Additionally, the study investigated knowledge transfer needs for the scale up of similar projects in Ireland. Lessons include: (1) Farmers require more upland specific research in order to address both production and environmental issues. (2) New information derived from this research is likely to be best received through traditional information sources such as newspapers as opposed to more innovative digital methods. (3) Farmers wish to have the development of future upland agri-environment schemes carried out in a manner that broadly resembles a locally led bottom up approach to their design and implementation.

Irish and European agriculture face significant challenges in terms of sustainability and food and nutrition security, which has been further challenged due to crises such as the Covid-19 pandemic and the escalating war in Ukraine. Making our food supply more sustainable brings about new challenges for actors in the food value chain. Innovation plays a key role in assisting actors in local systems to respond effectively to rapid changing environments. The EIP-AGRI recognises the key role agricultural advisors have in facilitating change through interactive innovation and therefore this new role requires an evolving set of competencies. This study examines the best practices and competencies of agricultural advisors assisting in interactive innovation. This research was conducted through the analysis of nine interactive innovation case studies from across Europe, and a survey of 56 respondents from agricultural extension managers across Europe. To add an Irish perspective a comparative analysis was conducted with the use of the current competency profile of Agricultural Development Officers (ADO) within Teagasc. Additionally, responses within the European survey of Teagasc managers were individually analysed to understand their current perspectives on what is required for interactive innovation. This was reinforced with the use of two semi-structured interviews of senior agricultural extension managers within Teagasc. On analysis of the data from the case studies and survey, an inventory of best practices and competencies contributing to successful interactive innovation was established. The study found that an extension organisation has a positive influence on the enabling environment of interactive innovation. The output of this research is a ‘Success Profile for Interactive Innovation’ which identifies the best practices, competencies and enabling environment for interactive innovation . As this is a relatively new and under researched area, these results offer a key foundation for the requirements of agricultural advisors in fostering interactive innovation. Through a comparative analysis of the success profile and the current competency profile of Teagasc ADO, similarities and differences were documented. Findings of these were reinforced by the key informant interviews, which show that despite some recent actions undertaken by the organisation, the awareness of the need for interactive innovation has not fully permeated the organisation. This is evidenced by the outdated competency profile for hiring, evaluation and promotion activities within the organisation. Organisational influences may affect the advancement of interactive innovation by agricultural advisors, and without actively encouraging these best practices and competencies they will continue to be undervalued within the organisation.

Background: Climate change, food demand and diet-related disease underline an urgent need for more sustainable and healthy food practices. Dietary guidance in the form of Sustainable Food Based Dietary Guidelines have been recommended at a national level to mitigate the environmental impact of food consumption, while improving health. For the Irish population to transition to sustainable diets, an improved knowledge base is required on the quality of current dietary patterns and the environmental impact of such. Objective: This thesis was designed to analyse diets reported in the Irish Population from a nutrition, environment, and cost perspective, and to complete preliminary modelling of healthier and more sustainable diets for sub-groups of the population. Methods: Food intakes on children, teenagers, and adults were taken from IUNA food consumption databases (FCDB). Nutrient based diet quality scores were calculated and evaluated as a metric of diet quality. Environmental data on greenhouse gas emissions and water use were taken from a UK life cycle assessment study, and agricultural impacts (cropland, nitrogen, and phosphorous use) from the FAOSTAT database to adults. A food price database was compiled, and dietary optimisation was completed using FICO Xpress software. Results: An evidence base was created by assigning three nutrient based scoring systems and linking data on environmental factors and food price to the FCDBs. In the nutritional analysis, teenagers and young adult females had significantly lower nutritional adequacy than the rest of the Irish population (58% probability of meeting nutrient recommendations). Lower nutritional adequacy was highlighted in females, those with a lower education level, and those from a more urban location. The Irish population was found to exceed planetary boundaries for GHGe (by up to 226%) but were well within the planetary boundaries for water use (<40%) across all groups. In relation to the agricultural boundaries, adult diets exceeded planetary boundaries considerably for all factors, from 277% - 382%. Dietary expenditure was found to be linked to life stage, and average cost ranged from €3.80 to €11.70 per day. Healthier diets were found to be more expensive (by €1.82 to €4.74 per day) and adults in education had a significantly higher dietary expenditure than all other social class groups (€10.90 per day). Dietary expenditure was found to be directly associated with environmental impact, and this may present a secondary motivation for consumers to transition to sustainable diets in Ireland. Affordable, environmentally, and nutritious food categories (e.g., milk, potatoes, cruciferous vegetables) and foods with multiple negative benefits were identified (unprocessed white meat and dishes, meat alternatives and dishes, vegetable soup and dishes, high energy beverage.). In the dietary modelling, GHGe reductions varied between population sub-groups (45% to 67%) and improvements of nutrient intakes ranged from 20% to 56% closer to nutrient recommendations. Several nutrients were improved from baseline diets in the Irish population (e.g., folate, iodine, and vitamin E) although inadequacy was introduced for nutrients in some population groups (e.g., biotin, cobalamin, and selenium). Conclusion: This thesis includes an in-depth analysis of nutrient intakes, environmental impact, and dietary expenditure across the Irish population and successfully trialled a methodology for integrating these factors to design sustainable diets which consider dietary preferences. The diversity of consumption patterns, nutritional needs, environmental impact, and dietary expenditure found between sub-groups highlight a need for context-specific research and subsequent guidelines.

AbstractThis thesis evaluated the basis of calcium-protein interactions in casein systems in order to develop novel casein-based food matrices with different structures and functionalities. Initially, in Chapter 2 the effects of calcium chelating salts (CCS) (disodium phosphate and trisodium citrate) on calcium-ion activity (ACa++), calcium distribution and protein solubility were investigated in model CaCl2 solutions (50 mmol L-1) and rennet casein dispersions (12 % w/w). In both model systems, adding trisodium citrate either alone or as part of a mixed chelating salt system resulted in high levels of dispersed “chelated” calcium; conversely, disodium phosphate addition resulted in lower levels, while the ACa++ decreased with increasing concentration of both CCS. Addition of either salt resulted in only a modest increase in soluble protein. Hence, the results suggested that CCS may play a more subtle role in modulating hydration during manufacture of casein-based matrices than simply solubilising calcium or protein. Therefore, despite the fact that the rennet casein dispersion used was relatively concentrated, an even more concentrated protein system was required to clarify the role of calcium chelators in casein hydration and matrix formation during manufacture of concentrated casein-based food matrices e.g. processed and analogue cheese.Hence, this work was further built upon in Chapter 3, where a small-scale manufacturing protocol for concentrated casein-based food matrices was developed using a Thermomix. Manufacture was stopped at various time-points, and the matrix formed and any free liquid still remaining were collected. The dispersed and insoluble phases were separated by centrifugation and the calcium (total calcium and ACa++) and protein contents of the dispersed phase analysed. The levels of calcium in the dispersed phase increased and ACa++ decreased during manufacture of casein matrices formulated with CCS; ~23 % of the total calcium was solubilised by the end of manufacture. In the absence of CCS, the levels of calcium solubilised were significantly (P < 0.05) lower at equivalent processing times and remained unchanged as did ACa++, throughout manufacture. The level of protein in the dispersed phase was low (≤ 3 % of total protein), but was significantly (P < 0.05) higher for the matrices containing CCS. The results obtained strongly suggested that the role of CCS was mainly to deplete colloidal calcium by partial solubilisation, which reduced calcium-mediated cross-linking sufficiently to allow adequate protein solubilisation to occur for fat emulsification. All of which contributed to successful matrix formation and stabilisation. The results generated suggested that only ~23 % of colloidal calcium needed to be solubilised to form a hydrated and functional casein-based food matrix. This lead us to believe that a similar attenuation of calcium mediated cross-links might possibly be achieved by simply reducing the total calcium concentration of these matrices by a similar proportion.Therefore in Chapter 4 casein-based food matrices with different calcium levels (1080-37 mg.100 g-1) were manufactured by mixing rennet and acid casein. At intermediate calcium levels (673-358 mg.100 g-1) homogeneous matrices were formed without CCS after relatively short processing times. However, homogeneous matrices with high (≥ 775 mg.100 g-1) or low (≤ 37 mg.100 g-1) calcium levels could not be produced without CCS. On cooling the CCS-free matrices with intermediate calcium levels formed functional cheese-like structures although they had lower hardness, flow on melting and G values at 25 C than conventionally formulated high-calcium matrices made from rennet casein with CCS. The results obtained demonstrated that by manipulating total calcium concentration, it was possible to form hydrated casein matrices to meet a range of functional and compositional requirements suitable for different end-use applications, without the use of CCS. The elimination of CCS provided a means of reducing the sodium content of these casein matrices by up to 60 % and also presented the opportunity to formulate end-products with cleaner labels.The sensory acceptability of casein matrices with low levels of calcium (357 mg.100 g-1) manufactured without CCS was investigated in Chapter 5. These matrices were flavoured with different types of enzyme modified cheeses (EMCs) and of those examined; Emmental was the most preferred by sensory panellists. The sensory acceptability of EMC flavoured casein matrices with different fat levels was also investigated. Firstly, the results of this study demonstrated that it was possible to produce full, half and reduced fat casein matrices without CCS. Furthermore, the results showed that although full-fat flavoured matrices were most preferred by sensory panellists and were rated higher in terms of their texture, flavour and overall liking; there were no significant differences (P > 0.05) detected between matrices containing half or reduced fat levels for any of these attributes.In Chapter 6 CCS-free casein-based matrices prepared with different types of lipid (i.e. milk fat or rapeseed oil) were formulated with high (774 mg.100 g-1) or low (357 mg.100 g-1) calcium levels again by blending rennet and acid casein. Their physico-chemical characteristics (i.e. composition, texture, microstructure and water mobility) and in vitro digestibility were compared to conventionally formulated high-calcium (723 mg.100 g-1) casein matrices made from rennet casein with CCS. The CCS-free, high-calcium matrices were significantly (P < 0.05) softer than those with low calcium levels and showed the highest rates of disintegration during simulated gastric digestion. Despite having a higher moisture-to -protein ratio, the high-calcium matrices containing CCS had broadly similar hardness values to those of high-calcium concentration prepared without CCS, but had higher cohesiveness. The high-calcium matrices containing CCS had quite a different microstructure and increased water mobility compared to those made without CCS and showed the slowest rate (P < 0.05) of disintegration in the gastric environment. Gastric resistance was shown to be unaffected by the type of lipid phase present in the matrix. Conversely, fatty acid release was similar for all casein matrices prepared from milk fat, however, high-calcium matrices (CCS-free) prepared from rapeseed oil showed higher lipolysis. The results demonstrated that modifying the composition (i.e. calcium concentration, moisture to protein ratio, inclusion of CCS) and consequently the physical characteristics (e.g. texture, microstructure and water mobility) of casein-based food matrices affects their behavior during in vitro digestion. In particular, the results obtained showed that the physical properties of such matrices could be modified to alter resistance to gastric degradation which may have consequences for the kinetics of nutrient release and delivery of bioactives sentitive to the gastric environment.

A major challenge for farmers is to produce safe food in an environmentally sustainable manner. Thus, the agricultural education that farmers receive must reflect this challenge and must appropriately equip and prepare young farmers for their role as custodians of the landscape. In 2018, Teagasc published the ‘Teagasc Education Vision Report’ outlining the future education and training needs of the land sector. This report incorporated the views of key national and international educationalists and stakeholders. Included as one of the goals and recommendations of this report is to ‘Develop learners’ knowledge, skills and competence to meet the changing requirements of the 21st Century land sector occupations. Central to this is embedding sustainable farming knowledge and skillsets in future land sector curricula. The ability to farm sustainably is a key competency in the 21st Century, as the agri-food industry is faced with more environmental challenges than ever before. The aim of this study is to identify teaching and learning strategies that are most likely to; resonate with Teagasc full time agricultural students and advance their thinking, appreciation, and understanding of agri-environmental sustainability. This study employs a mixed methods approach, combining student and teacher surveys, key informative interviews with peer agricultural education institutions and a teacher focus group. The findings support the importance of practical delivery and hands on learning, with college farms playing a pivotal role in demonstrating sustainable farming practices. The findings support a holistic approach, where sustainable farming knowledge is integrated into every module completed by agricultural students, effectively conveying the message that as farmers, they are working with nature not against nature. This study also advances new information in the area of effective teaching and learning strategies to enhance knowledge and understanding of sustainable farming.

Maximising both the utilisation of grazed pasture and cow production efficiency on-farm is highly beneficial in order to build a more sustainable and resilient dairy system. The objectives of this thesis were to identify pasture management strategies in autumn and spring to increase the proportion of utilised pasture while also evaluating various efficiency metrics and identifying animal characteristics associated with the efficient conversion of grazed pasture into high value milk output. Over 3 consecutive years, 144 Holstein-Friesian (HF) and Holstein-Friesian × Jersey crossbred (JFX) dairy cows were randomly assigned to 1 of 3 pasture availability (PA) treatments with a target average pasture cover (APC) of 800, 600 and 400 kg DM/ ha for high (HPA), medium (MPA), and low (LPA) on December 1. Grazing rotation length during the 11-wk measurement period in autumn was extended by +13 and +7 days for HPA and MPA, respectively, beyond that required by LPA (37 days) while all animals were housed at similar dates at the end of the grazing season. Besides achieving significant differences in APC and therefore pre-grazing herbage mass, PA had no significant impact on dry matter intake (DMI), milk production, or body condition score (BCS) in late lactation. During the first grazing rotation in spring, daily herbage allowance and total pasture utilised were greatest for HPA (11.7 kg DM/cow and 4,099 kg DM/ ha), intermediate for MPA (10.2 kg DM/cow and 3,319 kg DM/ ha) and lowest for LPA (8. kg DM/cow and 2,794 kg DM/ ha), with the deficit covered by additional grass silage supplementation so that total feed allowance did not differ between PA. There was no effect on daily or cumulative milk yield or milk composition in early lactation. Furthermore, an evaluation of a cost-effective efficiency parameter calculated as the annual fat and protein (milk solids; MS) production per unit of mid-lactation BW demonstrated that highly efficient grazing animals were characterised by a greater and more consistent daily MS yield, an increased DMI earlier in lactation and a greater intake per kg BW. Moreover, the most efficient animals also showed a greater MS yield both per kg of BW and per kg of DMI. An analysis evaluating the production efficiency of HF and JFX on commercial dairy farms identified Jersey crossbred animals to be more efficient in terms of MS yield per unit of mid-lactation BW and total energy requirement per kg of MS produced. However, large variation existed between farms (0.73 to 1.14 kg MS/ kg BW) and between animals within herds (0.42 to 1.47 kg MS/ kg BW). The results from this thesis corroborate the importance of achieving adequate pasture supply at the commencement of calving so that grazing days per ha and the utilisation of grazed pasture can be maximised, irrespective of between year weather and pasture growth variations. Equally important is the identification and breeding of elite animal genetics capable of harvesting additional quantities of fresh pasture as the cheapest feed source particularly in spring and efficiently converting it into a high value milk output.

Soil management and the agricultural methods used to establish crops is regarded as one of the most important applications governing crop productivity. Soil compaction is created by conventional agricultural systems. Coupled with a cool, wet Atlantic climate such as Ireland and the UK, machinery trafficking can have a negative impact on soil structure and crop performance. To date, there is a dearth of studies which examine the impact of tillage depth and machinery traffic on root system architecture, growth and yield. As roots provide water, nutrients and anchorage to the growing plant, their role for crop improvement and resilience to climate change cannot be overstated. However, root knowledge remains limited because soil is opaque , making root and soil studies complex. This research uses X-ray computed tomography to unravel the in-situ root and soil interactions in field soils for the first time. The core objectives of this research were to use a novel method based on a combination of traditional two-dimensional (2D) and more advanced three-dimensional (3D) image analysis technologies. The study assessed the impact and interaction between four crop establishment systems and three trafficking regimes on crop performance and root growth of winter wheat (Triticum aestivum L.) at three different stages of the crop growth cycle (Tillering, flag leaf and anthesis). The study was conducted over two growing seasons (2018/19 & 2019/20) and included three soil textures (loamy sand, clay loam and clay). Four tillage systems were used in the Irish site: Plough, till and sow (300 mm), deep tillage (250 mm), shallow tillage (100 mm) and zero tillage while ploughing was omitted from the two UK sites. Each establishment method was applied using three different trafficking regimes: conventional tyre pressure (1.5 bar), low tyre pressure (0.8 bar) and no traffic. The effect of crop growth, yield and corresponding effect on soil and root physical properties were studied. Further knowledge and insights into root behaviour and architecture has been achieved using X-ray CT. This study showed that field traffic significantly affects rooting properties resulting in reduced root surface area, volume, root length and root length density (RLD) (P < 0.001) in long term tillage trials. It causes an increase in root thickness (root diameter) which results in shorter root systems with limited soil exploration for water and nutrients. Trafficking increases soil penetration resistance (P < 0.000) and bulk density (P < 0.05) compared to untrafficked soil which significantly affects soil porosity (P < 0.05). The compaction effects of trafficking are more pronounced in zero and shallow tillage systems when soil moisture is at field capacity during drilling, resulting in yield loss of + 30% in comparison to conventionally managed systems (plough, till & sow). Tyre pressure did not have a significant impact on rooting and soil properties but it generally slightly mitigated the effects of compaction on yield, rooting and soil physical properties. Overall, trafficking had a significant impact on crop yield (P < 0.001). Tillage practice had a significant effect on soil physical properties, crop yield and root growth. The results suggest that loamy sand sites benefit from zero tillage systems through increased rooting length, RLD and moderate compaction benefits which possibly increased water and nutrient retention. The results suggest that deep tillage systems create a porous structure increases rooting properties but reduces moisture retention. Moreover, this work has shown that soil texture has a significant influence on root growth. Moderate compaction benefits of root growth in clay soils reduced rooting but increased crop yield significantly compared to sandy loam soils which caused plants to partition more carbon to root growth, leading to less crop yield. This work has shown that root system architecture can be measured in field soils.

In this thesis the potential applications of non-thermal technologies, including pulsed electric fields, low frequency ultrasound and high pressure, at various stages in the production process of protein hydrolysates were investigated. These technologies have the potential to induce structural changes at a molecular level to protein substrates.The first area investigated was the use of selected non-thermal technologies as pre-treatments for a caseinate substrate prior to enzyme hydrolysis. It has been shown by other authors that pulsed electric field, low frequency ultrasound and high pressure treatments can induce protein denaturation under specific settings and this may increase their susceptibility to subsequent hydrolysis. The pre-treatments of 10% (w/v) sodium caseinate employed were: pulsed electric field treatment of 34 kV cm-1 with a total specific energy of 276.81 kJ kg-1, low frequency ultrasound at a frequency of 20 kHz (amplitudes of 170 µm and 136 µm) and a high pressure treatment of 400 MPa, each applied for 30 minutes. The results from this investigation indicated that low frequency ultrasound applied for 30 minutes at an amplitude of 136 µm is the most promising pre-treatment as a ~33% reduction in the hydrolysis time was achieved, while all other pre-treatments investigated had, at best, a marginal effect on the hydrolysis rate.Low frequency ultrasound (24 kHz) was also applied during enzymatic hydrolysis of sodium caseinate to investigate if the cavitational effect could lead to increased mixing in the system, thus leading to an enhanced rate of hydrolysis. Amplitudes of 20, 40 and 60 µm were investigated with stirring speeds ranging from 100-600 rpm and protein concentrations of 5-15%. It was found that the rate of the hydrolysis could be enhanced by applying ultrasound but only under very specific conditions. For a stirring speed of 400 rpm with a protein concentration of 10% (w/v), application of ultrasound at amplitudes of 20 µm and 40 µm decreased the hydrolysis time by ~25% and ~45% respectively. All other ultrasound conditions investigated lead to either an increased hydrolysis time or had a marginal effect over the control indicating that there is a narrow optimum range of conditions in which this phenomenon occurs.Finally high pressure was compared to thermal treatments as a means to inactivate enzyme activity (e.g. for the termination of a hydrolysis reaction). The enzyme, Protamex®, was subjected to thermal and high pressure treatments when dispersed in water or in a 10% (w/v) sodium caseinate substrate solution. The presence of the caseinate substantially increased the stability of the enzyme to heat treatment. Similarly the enzyme was more pressure susceptible in water than in the presence of sodium caseinate, again indicating a protective effect of the substrate. Over 90% inactivation was achieved at pressures ≥400 MPa with holding times of 30 minutes in water, whereas this level of inactivation required 600 MPa in the sodium caseinate solution. No significant inactivation occurred at pressures <400 MPa.During the course of this work it became apparent that these non-thermal technologies only have a positive effect on hydrolysis under a very narrow range of conditions and careful process optimisation is required. All of the investigations conducted were also at laboratory scale and up-scaling of these experiments may result in different outcomes.

The positive effect of vitamin D (vit D) on health and resistance against infectious diseases, particularly tuberculosis (TB) is well recognized. However, research has predominantly focused on murine and human species and functional data in bovines is limited. The aims of this project were: chapter 2&3) To investigate the effect of 1,25(OH)2D3 on the microbicidal and immunoregulatory activities in peripheral blood leukocytes (PBL) and on neutrophils. Chapter 4) To develop a model to drive divergent 25(OH)D circulating levels in dairy calves, and Chapter 5) To investigate the influence of differential 25(OH)D circulating levels on the microbicidal and immunoregulatory activities of PBL following and ex-vivo BCG challenge. Results from chapter 2 showed that 1,25(OH)2D3 supplementation significantly increased BCG killing on PBL to 65.7% compared to 49.1% in the untreated blood. Serial cell subset depletion showed that depletion of granulocytes had the greatest impact on BCG growth and lead to a significant enhancement of bacterial colonies. Significantly enhanced bacterial killing was observed in CD14neg PBLs treated with 1,25(OH)2D3 and a similar trend was observed in Granneg subsets (P = 0.06). In contrast, depletion of CD4+ or CD8+ T cells individually or in combination (CD3+) had no impact on mycobacterial control. Data also showed that 1,25(OH)2D3 stimulation increased reactive oxygen species (ROS) production and decreased overall BCG growth in PBLs. 1,25(OH)2D3 increased the expression of a cluster of genes including DEFB7, TAP, ELANE, CCL2, CXCL10, IFNB, IL33 and PKR implicated in activation of the innate immune response to mycobacteria. Results from chapter 3 confirmed the microbicidal effects of 1,25(OH)2D3 on neutrophils showing an enhanced killing against BCG and M. bovis. Then, in chapter 4 calves were supplemented with vit D3 from birth to 7 months age. Two control groups (Ctl-In, Ctl-Out) received a diet containing 6,000 IU/Kg of vit D3 in milk replacer and 2,000 IU/Kg in rations, and two groups (VitD-In, VitD-Out) were fed with 10,000 IU/Kg of vit D3 in milk replacer and 4,000 IU/Kg in rations. After weaning, Ctl-Out and VitD-Out groups were moved outdoors, whereas Ctl-In and VitD-In groups were kept indoors. Results showed a high incidence of vitamin D deficiency (VDD) at birth with mean 25(OH)D of 7.64 ±3.206. Significant elevated 25(OH)D concentrations were observed after weaning, with the maximal 25(OH)D level achieved in VitD-Out reaching 60.86±7.318. Greatest divergence in haematology profile was observed between Ctl-In and VitD-In groups, with Ctl-In calves showing an elevated count of neutrophils, eosinophils, and basophils associated with reduced 25(OH)D concentrations. Neither IL-8 nor ROS production in serum were significantly different between calves. In chapter 5 the assessment of the microbicidal activity and immunoregulatory effect to an ex-vivo BCG challenge was performed on Ctl-In and VitD-In groups. Results showed higher bacterial killing in the VitD-In group (48.0%) in contrast to Ctl-In group (29.5%). Besides, increased production of ROS and NO was detected in VitD-In calves. Whereas serum concentrations of IL-1ß and IL-8 were significantly lower. Likewise, a significant downregulation of a cluster of genes including IL1B, IL1R1, TNFA, CXCL1, CXCL2, CXCL5, CXCL8 was detected in VitD-in calves relative to Ctl-In animals. Collectively, results showed that 1,25(OH)2D3 improved mycobacterial killing in bovine PBLs via the synergistic activity of monocytes and granulocytes and enhanced activation of innate immunity. Evidence indicates that vit D3 supplementation boosts antimicrobial and innate immune responses but modulates excessive inflammation which may be detrimental for the outcome to infection. Finally, results identified neutrophils as one of the principal targets of vit D modulatory effects.

Primary data was gathered from commercial grass-based dairy farms in the south and south east of Ireland. Nutrient use at the farm, field and paddock scale was characterised and evaluated simultaneously, to determine the sustainability of nitrogen (N), phosphorus (P) and potassium (K) management practices. Additionally, a spatially explicit precision nutrient advice strategy (including soil pH measurement, soil test for P (STP) and K (STK) concentrations), was implemented on the selected farms. The nutrient balance (BAL) i.e. nutrient source pressure, and use efficiency (UE) indicators, were evaluated across these farms and spatial scales from 2015 to 2017, while changes in soil fertility were monitored from 2015 to 2018. As well as this, herbage nutrient concentration was assessed through spring, summer and autumn of 2015 and 2016 at the paddock scale. Mean nitrogen use efficiency (NUE), and phosphorus use efficiency (PUE), were found to be significantly lower (p < 0.05) at farm scale (NUE: 28% and PUE: 52%), compared to results at field scale (NUE: 57% and PUE: 100%). Mean potassium use efficiency (KUE), was found not to be significantly different between these scales (KUE: 56% and 91%, respectively). With regard to nutrient source pressure, phosphorus balance (PBAL) was found to be significantly higher (p < 0.05) at the farm scale than at the field scale (9 and 6 kg P ha-1, respectively), while the differences in nitrogen balance (NBAL) (165 and 139 kg N ha-1, respectively) and potassium balance (KBAL) (23 and 39 kg K ha-1, respectively) were not found to be significant between scales. Furthermore, variability (denoted by CV: Coefficient of Variation) in UE was found to be substantially larger between individual fields and paddocks (CV, 67%, 74% and 127% for N, P, and K, respectively) than between individual farms (CV, 39%, 33% and 76% for N, P, and K, respectively). Variability in BAL, was also found to be substantially higher between individual fields and paddocks (CV, 77%, 294% and 179% for N, P, and K, respectively) than between individual farms (CV, 34%, 58% and 86% for N, P, and K, respectively). Indicators of soil fertility (soil test values and soil optimum indices distribution) and indicators of nutrient management (BAL and UE) were found to develop towards more agronomically optimum levels. For example, mean results for paddocks across these farms showed that low fertility paddocks increased their soil pH to 6.3 or medium/adequate soil levels, while the mean results for high fertility paddocks show that STP decreased to 6.7 mg l-1, and STK decreased to 142.9 mg l-1, closer in range to agronomic optimum soil levels. Mean field scale PBAL and KBAL surpluses decreased significantly between 2015 and 2016 also (from 7 to 4 kg P ha-1 and 52 to 34 kg K ha-1). Finally, it was shown that the paddock scale herbage nutrient concentration strongly relies upon soil nutrient supply and soil fertility management. STK level was the primary factor of herbage K and Calcium (¿2 = 0.26 and 0.11, respectively) while soil test Magnesium level was the primary factor of herbage Magnesium (¿2 = 0.28) and STP level was the primary factor of herbage P (¿2 = 0.35). Soil pH level was the primary factor of herbage Manganese and Calcium (both ¿2 = 0.15). The results presented in this thesis show that the scale at which nutrient use indicators are observed (e.g. farm or field/paddock), has a significant influence on the apparent nutrient efficiency and nutrient source pressure of specialised dairy farms. This has potentially important implications for agri-environmental policy makers, nutrient regulation and nutrient monitoring systems.

The purpose of this study has been to evaluate how academic student engagement could be enhanced within vocational agricultural education in Ireland. This was identified as an issue that needed to be addressed by the Department of Education and Skills as part of whole college evaluations of vocational agricultural courses where Teagasc fund the delivery. A critical finding from this study has been the importance of ‘Course Design’ in creating an authentically engaging learning experience for students. The ‘Course Design’ is especially important when considering implementing an engaging teaching approach such as a student-centred learning approach. Findings from this study have shown that currently, in Teagasc, the ‘Course Design’ does not constructively align with student-centred learning. This study adopted an action research design and in phase 1, investigated why academic student engagement was low with the conventional teaching approach being evaluated. The key finding was that students struggled to engage with one type of module i.e. ‘Core Modules’, the most. Classroom observations on this type of module resulted in 0% categorised as ‘High Engagement’ (0/16 of the ‘Core Module’ classes observed). In addition, data gathered from focus groups with teachers highlighted the lack of flexibility in the design of modules, with teachers citing learning outcomes, assessment strategies and the quality assurance process as constraints. The student focus group highlighted that students lacked an intrinsic motivation to be interested in ‘Core Modules’, combined with the lack of interest in being ‘lectured to’ excessively as part of these modules. Phase 2 involved taking action on these findings and the design of an intervention through a pilot module attempting to use a student-centred learning (SCL) approach. Problem Based Learning was identified as a suitable SCL approach that could be implemented in an attempt to enhance academic student engagement compared to phase 1. A course redesign was used to develop the pilot module to attempt to align with PBL. This pilot module resulted in a substantial increase in the number of classes categorised as ‘High Engagement’ with 88% rated as high (21/24 classes observed categorised as ‘High Engagement’). Despite this positive result from phase 2, there were still a number of issues and conflicts with the ‘Course Design’ that arose during the pilot module. As such, it was important to reflect on this and phase 3 represented an investigation into these issues and conflicts. Phase 3 represented the evaluation phase of this action research project. This aimed to evaluate why the current course design creates barriers to using student-centred learning approaches. Four key aspects of ‘Course Design’ were analysed and compared against a student-centred design; 1) Course Aims and Outcomes 2) Module Design 3) Course Structure 4) Course Organisation. The key findings from this phase highlighted that the course structure and module design need to be redesigned to align with a student-centred learning approach. These are two aspects of ‘Course Design’ that are more complex to change which means they will also take longer to make changes to. In addition, it also does not mean that the ‘Course Aims and Outcomes’ and ‘Course Organisation’ are not important, they still play a vital role. They do, however, need the course structure and module design to support the use of student-centred learning. This highlights not the importance of any individual aspect of ‘Course Design’ rather how these four key aspects work together. The principles of ‘Course Design’ outlined in this study, teaching approaches and constructive alignment are transferable to those delivering courses in vocational (further) education and could also be considered by those delivering courses in higher education.

Perennial ryegrass is the dominant pasture species used in temperate grazed grasslands. The productivity of perennial ryegrass is critical to the economic sustainability of grassland farms in temperate regions yet little information is available on the performance of perennial ryegrass varieties when exposed to grazing conditions on commercial grassland farms. As the regulation of fertiliser use on commercial farms reduces the permitted amount of chemical nitrogen to be applied more farmers are including leguminous species in grazing swards to increase dry matter production; this effect is largely a result of the biological nitrogen fixation facilitated by legumes which increases soil nitrogen availability. Recently, further increases in dry matter production have been observed where forage herbs are included with grass and legume species in multispecies swards. Currently, little data are available from intensively grazed swards regarding individual species contribution of forage herbs to sward dry matter production. Pasture species are usually evaluated in short term mechanically-defoliated plot systems which do not fully capture the range of stresses or interactions that a sward is subjected to in grazing scenarios. Data are presented in this thesis which outline the contribution of novel forage herbs to grazed swards over multiple growing seasons under intensive grazing. Further data presented in this thesis will outline how evolving technology, in the form of PastureBase Ireland, can allow for the robust evaluation of pasture species on commercial farms over multiple years; this method is demonstrated for perennial ryegrass in the current work yet can be adapted to any forage species and associated varieties.

The objective of this study was to investigate the effect of increasing stocking rate (SR) and/or extending grazing season (GS) length on pasture and animal productivity along with soil physical and structural properties on a wetland soil type. The study was a multi-year (2017 to 2020, incl.) whole farm systems evaluation with a 2 x 2 factorial experimental arrangement of treatments. The systems evaluated comprised 2 grazing season lengths (average (AGS; 205 days) and extended (EGS; 270 days) and 2 whole farm stocking rates (medium (MSR; 2.5 cows/ha) and high (HSR; 2.9 cows/ha). The study design was such as to create 4 grazing system intensities (500, 600, 700 and 800 grazing days per hectare yr-1). In 2017, cows were randomly allocated to one of the 4 whole farm systems pre-calving and remained on the same treatments for the duration of the study. Soil treading measurements were taken in 2018 and 2019. There were no significant differences in total average annual herbage production (14,133 +/- 538 kg DM per hectare) or sward chemical composition between GS and SR treatments over the 4 year period with the exception of CP content which was lower (P<0.01) for EGS (211 g/kg) compared with AGS (218 g/kg). Grazed pasture production was significantly (P<0.05) increased in EGS treatments (+758 kg DM/ha) compared with AGS (9,917 kg DM/ha), whereas conserved silage DM production was greater (P<0.05) for AGS (+716 kg DM/ha) compared to EGS (3,583 kg DM/ha). Neither GS nor SR had a significant impact on daily or cumulative lactation milk and fat plus protein production per cow (5,039 and +/-440 kg, respectively). While both Year and Season had a significant effect on soil treading characteristics, there was no significant impact of SR or GS. Increasing grazing days per hectare resulted in increased milk fat plus protein yield per hectare based on increased grazed pasture utilization resulting in an overall economic gain of €6.30 per additional grazing day per hectare. These results add further credence to the important additive contributions of both extended grazing and appropriate SR to maximise pasture and land resource utilization by increasing the number of grazing days per hectare in dairy systems on marginal soils with no negative effect on soil treading characteristics

Seafood, such as fish and shellfish, contribute important macro- and micro-nutrients to the human diet and are considered an important part of a healthy diet. Seafood is a good source of protein, essential fatty acids and micronutrients such as iodine, selenium, zinc and vitamin D. Research has shown that seafood consumption can help protect against lifestyle diseases such as cardiovascular disease (CVD), diabetes and inflammatory diseases. Previously conducted National Food Consumption Surveys, in Ireland, lacked information on seafood. This thesis aimed to examine the characteristics of seafood consumers in Ireland, as well as contribution of seafood to nutrients intakes in Irish seafood consumers, determine motives underlying their daily food choices. Participants were recruited for the Seafood Consumption and Risk Exposure Study (SCaRES) and their data was collect via the web-based dietary assessment tool FoodBook24. Participants were requested to completed 3 24-hour dietary recalls in 2 weeks, in addition to a demographic and food choice questionnaire (FCQ). Analyses was conducted on the SCaRES dataset, along with an additional dataset collected prior to this study known as the DietIreland Proof of Principle (PoP) study. Analysis of the dietary intakes of self-reported seafood consumers in Ireland demonstrated that the seafood consumers in this study are meeting the current dietary recommendations for seafood consumption in Ireland, consuming on average 75.37g/day of total seafood. Respective mean daily intakes of oily fish, white fish and shellfish were 46.23g/day, 73.04g/day and 43.17g/day. These intakes of seafood were also within sustainability guidelines, set out within the new Eat Lancet report. Our analysis indicated that seafood contributed significant amounts of key nutrients to the diet of these consumers, namely vitamin D, vitamin B12 and Omega-3. Analysis of the food choice motives of this population suggested that seafood consumers placed importance on the sensory characteristics, as well as the health attributes or the foods they choose to eat. In summary, this work has characterised seafood consumers in Ireland. In addition, it has provided valuable information on the nutritional quality of this group’s diet and on their food choice motives. The information that this thesis has provided is useful for a wide range of organisations, including, but not limited to, government bodies for informing public health policy and developing public health campaigns, retailers and businesses seeking to promote sales of seafood, and research teams seeking to investigate seafood consumption in specific populations or for biotoxicity research.

Tanzania, a low-income country with high dependence on agricultural activities, has a large number of poor people who mostly reside in rural areas and are faced with food insecurity and malnutrition. Even with the increase in the Gross Domestic Product (GDP), the share of agriculture to GDP has continued to decline and income distribution remains poor. The challenge of food security has meant that Tanzania has a score of 28.8 in the 2017 Global Hunger index and the number of undernourished people has continued to increase. The local food economy in Tanzania plays a great role in influencing incomes and food security of rural households, and therefore it is important to examine the linkage between local food economies and household food security and nutrition. This study was conducted in two districts of Tanzania that have different agro-ecological and economic conditions, Kishapu in the Shinyanga Region and Mvomero in the Morogoro Region and examined the factors within the local food economy that affect household food security status. These districts were selected basing on nutritional vulnerability, lack of nutritional interventions and differences in rain patterns, farming practices and economic activities. Both qualitative and quantitative data were collected in two phases (before and after harvest) using household surveys in 2014 with the aid of structured questionnaires from 506 households as well as monthly market price surveys in 2014. Also, key informant interviews and focus group discussions were used to collect qualitative data. Four income quartiles were identified from the income data as well as four farming systems from the crop and livestock production data. Households in Mvomero had higher incomes, better market access, diversified income sources and better food security. Diet costs, influenced by price and seasons, impacted lower income households resulting to poor diet choices and more food insecurity. Households also had fewer means of coping with food and income shortages and would resort to consuming less or selling livestock and borrowing. Policies and strategies to improve farm production and farm incomes, improve market access, increase non-farm opportunities have meaningful implications for low-income rural households. These may include initiatives to improve transport and communications infrastructures, access to credit and market information, as well as nutritional education to households.

Agricultural education plays a fundamental role in developing the future generation of young farmers. Over the past number of years, agriculture has undergone significant change with regard to production and consideration for the landscape and the environment within which farming communities reside. Conversely, education has experienced paradigm shifts relating to education programme delivery, instructional techniques, and the role of the teacher within the educational context. The purpose of this thesis is to explore the professional development needs of the agricultural educators involved in the delivery of vocational agricultural education and training programmes to the future generation of young farmers. Much research has been conducted regarding learners’ needs, the importance of vocational education and training programmes, and the learner experience within the vocational education and training sphere, however, little is known about the teachers’ experience in the delivery of such programmes. In addressing this intellectual gap, the thesis employs a mixed methods research paradigm consisting of three distinct research phases. The first phase employs an explanatory sequential mixed methods research design process to identify the specific professional development needs of the agricultural teaching population within the vocational education and training sector. The second phase furthers conceptual understanding of agricultural teacher professional development needs through the use of an exploratory sequential mixed methods research design to develop a professional development tool appropriate to the needs of the agricultural teaching population. Finally, the third research phase contributes a nuanced understanding of the primary and secondary motivators influencing young peoples’ further educational choice through the use of an in-depth exploratory research design. Findings from each phase in the data collection process are documented in the form of academic peer-reviewed paper publications developed based on findings within this thesis. In conclusion, this thesis contributes to theoretical and conceptual understandings of the study phenomenon relating to agricultural teacher professional development needs. The influence of policy, both nationally and internationally, are considered throughout the thesis given the effect of young farmer intervention on agricultural education programmes and the recruitment of agricultural teachers within the vocational education and training context.

This study examines a rural community’s engagement with practice-ready knowledge gathered by the SKIN (Short Food Supply Chain Knowledge and Innovation Network) Horizon 2020 project. The facilitation of the community at the heart of this study in creating a range of enterprise opportunities that reflect the history, heritage, culture and traditions of the area is clearly detailed. Participatory Action Research was used to implement a ‘bottom-up’ approach ensuring that the community participants were at the core of this project and were key decision-makers throughout the process. The use of tools from the SKIN multi-actor ‘toolbox’ along with the implementation of a range of methods and techniques including interactive innovation techniques are documented throughout. The researcher who acted as both facilitator and researcher also incorporates her reflections of the process into the study.