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Optimising mechanical separation of anaerobic digestate for total solids and nutrient removal
Get PDFPublication history: Accepted - 16 June 2023; Published - 28 June 2023.Mechanical separation of anaerobic digestate has been identified as a method to reduce pollution risk to waterways by partitioning phosphorus in the solid fraction and reducing its application to land. Separators have adjustable parameters which affect separation efficiency, and hence the degree of phosphorous partitioning, but information on how these parameters affect separation performance is limited in the literature. Two well known technologies were investigated, decanter centrifuge and screw press, to determine the most efficient method of separation. Counterweight load and the use of an oscillator were adjusted for the screw press, while bowl speed, auger differential speed, feed rate and polymer addition were modified for the decanter centrifuge. Separation efficiency was determined for total solids, phosphorus, nitrogen, potassium, and carbon, and the total solids
content of resulting fractions was measured. The decanter centrifuge had higher separation efficiency for phosphorus in all cases, ranging from 51% to 71.5%, while the screw press had a phosphorus separation efficiency
ranging from 8.5% to 10.9% for digestate of ~5% solids (slurry/grass silage mix). Separation by decanter centrifuge partitioned up to 56% of nitrogen in the solid fraction leaving a reduced nitrogen content in the liquid fraction available for land spreading; this nitrogen would most likely need to be replaced by chemical fertiliser which would add to the cost of the system. The decanter centrifuge is better suited to cases where phosphorus recovery is the most important factor, while the screw press could be advantageous in cases where cost is a limiting factor.This project was supported by The Bryden Centre. The Bryden Centre project is supported by the European Union’s INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPB). The
views and opinions expressed in this paper do not necessarily reflect those of the European Commission or the Special EU Programmes Body (SEUPB). The work was also supported by Queen’s University Belfast and the Agri-Food and Biosciences Institute in Northern Ireland
A machine learning approach to predicting plant available phosphorus that accounts for soil heterogeneity and regional variability
No full textPublication history: Accepted - 1 September 2023; Published - 20 September 2023.Purpose
Mehlich-3 extractable P, Al, Ca, and Fe combined with pH can be used to help explain soil chemical processes which regulate P retention, such as the role of Al, Ca, Fe, and pH levels in P fixation and buffering capacity. However, Mehlich-3 is not always the standard test used in agriculture. The objective of this study is to assess the most reliable conversion of Mehlich-3 Al, Ca, Fe, and P and pH into a commonly used soil P test, Morgan’s P, and specifically to predict values into decision support for fertiliser recommendations.
Methods
A geochemical database of 5631 mineral soil samples which covered the northern area of Ireland was used to model soil test P and P indices using Mehlich-3 data.
Results
A random forest machine learning algorithm produced an R2 of 0.96 and accurately predicted soil P index from external validation in 90% of samples (with an error range of ± 1 mg L−1). The model accuracy was reduced when predicted Morgan’s P concentration was outside of the sampled area.
Conclusions
It is recommended that random forest is used to produce Mehlich-3 conversions, especially when data covers large spatial scales with large heterogeneity in soil types and regional variations. To implement conversion models into P testing regimes, it is recommended that representative soil types/geochemical attributes are present in the dataset. Furthermore, completion of a national scale geochemical survey is needed. This will enable accurate predictions of Morgan’s P concentration for a wider range of soils and geographical scale.This work has been jointly supported by Geological
Survey Ireland and Teagasc (Terra Soil Collaborative Agreement
2018)
Natural Antimicrobials Block the Host NF-κB Pathway and Reduce Enterocytozoon hepatopenaei Infection Both In Vitro and In Vivo
No full textPublication history: Accepted - 19 July 2023; Published - 20 July 2023.The objective of this work was to investigate, for the first time, the antioxidant effect of a mixture of natural antimicrobials in an Enterocytozoon hepatopenaei (EHP) shrimp-gut model of infection and the biological mechanisms involved in their way of action. The study approach included investigations, firstly, in vitro, on shrimp-gut primary (SGP) epithelial cells and in vivo by using EHP-challenged shrimp. Our results show that exposure of EHP spores to 0.1%, 0.5%, 1%, and 2% AuraAqua (Aq) significantly reduced spore activity at all concentrations but was more pronounced after exposure to 0.5% Aq. The Aq was able to reduce EHP infection of SGP cells regardless of cells being pretreated or cocultured during infection with Aq. The survivability of SGP cells infected with EHP spores was significantly increased in both scenarios; however, a more noticeable effect was observed when the infected cells were pre-exposed to Aq. Our data show that infection of SGP cells by EHP activates the host NADPH oxidases and the release of H2O2 produced. When Aq was used during infection, a significant reduction in H2O2 was observed concomitant with a significant increase in the levels of CAT and SOD enzymes. Moreover, in the presence of 0.5% Aq, the overproduction of CAT and SOD was correlated with the inactivation of the NF-κB pathway, which, otherwise, as we show, is activated upon EHP infection of SGP cells. In a challenge test, Aq was able to significantly reduce mortality in EHP-infected shrimp and increase the levels of CAT and SOD in the gut tissue. Conclusively, these results show, for the first time, that a mixture of natural antimicrobials (Aq) can reduce the EHP-spore activity, improve the survival rates of primary gut-shrimp epithelial cells and reduce the oxidative damage caused by EHP infection. Moreover, we show that Aq was able to stop the H2O2 activation of the NF-κB pathway of Crustins, Penaeidins, and the lysozyme, and the CAT and SOD activity both in vitro and in a shrimp challenge test.We acknowledge Environtech, Dublin, Ireland for funding the PhD of Eugenia Butucel. Grant number 49650. The publication of this paper was supported through the University of Life Sciences King Mihai I from Timisoara doctoral grants
Ecological carrying capacity in mariculture: Consideration and application in geographic strategies and policy
No full textPublication history: Accepted - 24 January 2023; Published - 6 February 2023.Governance and management strategies for aquaculture development were examined for a select number of jurisdictions covering a range of marine aquaculture production to better understand the degree to which concepts of “Ecological Carrying Capacity” (ECC) are incorporated into management tools or permitting requirements for aquaculture development. Policies, regulations, and strategic plans were sought through professional knowledge and, at times, using web-based searches. Aquaculture ECC, defined here as, “the magnitude of aquaculture production that can be supported without leading to unacceptable changes in ecological process, species, populations, or communities in the environment,” was not strictly applied in any jurisdiction’s aquaculture policy documentation. A broadened search to consider the concept of aquaculture carrying capacity (CC) more generally was conducted. Of the ten nations examined, CC concepts could be found in policy documentation of several nations. The inclusion of CC concepts in policy and strategic planning can be used as part of a suite of management tools to promote sustainable aquaculture within FAO’s Ecological Approach to Aquaculture
The Impact on Cow Performance and Feed Efficiency When Individual Cow Milk Composition and Energy Intake Are Accounted for When Allocating Concentrates
Get PDFPublication history: Accepted - 27 June 2023; Published - 3 July 2023.The objective of this three-treatment, 12-week study (involving 69 dairy cows) was to test three methods of concentrate allocation on milk production efficiency. All treatments were offered a basal mixed ration of grass silage and concentrates, with additional concentrates offered to individual cows based on either milk yield alone (Control), milk energy output (Precision 1) or energy intake and milk energy output (Precision 2). Concentrate requirements were calculated and adjusted weekly. Control cows had lower concentrate dry matter intake (DMI; p = 0.040) and milk protein content (p = 0.003) but yield of milk and energy-corrected milk (ECM), energy balance, bodyweight and condition score were unaffected by treatment. Efficiency measures such as ECM/DMI and ECM/metabolizable energy intake were also unaffected by treatment. Less concentrates were used per kg ECM yield in the Control compared to the Precision treatments (p < 0.001). In conclusion, accounting for individual cow milk composition or milk composition combined with individual cow energy intake did not improve production efficiency compared to an approach based on individual cow milk yield only.This research was funded by Department of Agriculture, Environment and Rural Affairs and AgriSearch through the Research Challenge Fund, grant number 16-1-10
Relationship between ambient temperature at sampling and the interferon gamma test result for bovine tuberculosis in cattle
Get PDFPublication history: Accepted - 17 May 2023; Published online - 19 May 2023.Bovine tuberculosis (bTB) is a disease of significant economic and zoonotic importance, therefore, optimising tests for the identification of Mycobacterium bovis infected cattle is essential. The Interferon Gamma (IFN-γ) Release Assay (IGRA) can diagnose M. bovis infected cattle at an early stage, is easy to perform and can be used alongside skin tests for confirmatory purposes or to increase diagnostic sensitivity. It is known that IGRA performance is sensitive to environmental conditions under which samples are taken and transported. In this study, the association between the ambient temperature on the day of bleeding and the subsequent IGRA result for bTB was quantified using field samples from Northern Ireland (NI). Results of 106,434 IGRA results (2013–2018) were associated with temperature data extracted from weather stations near tested cattle herds. Model dependent variables were the levels of IFN-γ triggered by avian purified protein derivative (PPDa), M. bovis PPD (PPDb), their difference (PPD(b-a)) as well as the final binary outcome (positive or negative for M. bovis infection). IFN-γ levels after both PPDa and PPDb stimulation were lowest at the extremes of the temperature distribution for NI. The highest IGRA positive probability (above 6%) was found on days with moderate maximum temperatures (6–16 °C) or moderate minimum temperatures (4–7 °C). Adjustment for covariates did not lead to major changes in the model estimates. These data suggest that IGRA performance can be affected when samples are taken at high or low temperatures. Whilst it is difficult to exclude physiological factors, the data nonetheless supports the temperature control of samples from bleeding through to laboratory to help mitigate post-collection confounders
Greenhouse gas and ammonia emission mitigation priorities for UK policy targets
Get PDFPublication history: Accepted - 16 March 2023; Published online - 6th May 2023.Agriculture is essential for providing food and maintaining food security while concurrently delivering multiple other ecosystem services. However, agricultural systems are generally a net source of greenhouse gases and ammonia. They, therefore, need to substantively contribute to climate change mitigation and net zero ambitions. It is widely acknowledged that there is a need to further reduce and mitigate emissions across sectors, including agriculture to address the climate emergency and emissions gap. This discussion paper outlines a collation of opinions from a range of experts within agricultural research and advisory roles following a greenhouse gas and ammonia emission mitigation workshop held in the UK in March 2022. The meeting identified the top mitigation priorities within the UK’s agricultural sector to achieve reductions in greenhouse gases and ammonia that are compatible with policy targets. In addition, experts provided an overview of what they believe are the key knowledge gaps, future opportunities and co-benefits to mitigation practices as well as indicating the potential barriers to uptake for mitigation scenarios discussed.This work was supported with funding from the Scottish Government Strategic Research Programme (2022−2027, C2-1 SRUC) and Biotechnology and Biological Sciences Research Council (BBSRC)
(BBS/E/C/000I0320 and BBS/E/C/000I0330). We also acknowledge support from UKRI-BBSRC (UK Research and Innovation-Biotechnology and Biological Sciences Research Council) via grants BBS/E/C/000I0320 and BBS/E/C/000I0330, and Rothamsted Research Science Initiative Catalyst Award supported by BBSRC
Production pathways for profitability and valuing ecosystem services for willow coppice in intensive agricultural applications
Get PDFPublication history: Accepted - 14 January 2023; Published online - 20 January 2023Increasing agricultural sustainability is a key challenge facing the globe today. Energy crops, planted as riparian buffers are one way to support this, simultaneously mitigating water quality degradation and climate change. However, the economics of implementing such riparian buffer systems is under researched. Hence this work conducted a bottom-up economic analysis of willow coppice riparian buffers on a Northern Irish dairy farm, which is indicative of agricultural intensification across Europe. This work includes an economic assessment of a willow coppice riparian buffer strip, using harvested yield data from an established willow buffer site for the first time. It also considered the impact of harvesting technology on the economic performance of a willow coppice riparian buffer strip for the first time. The analysis considered three willow production pathways: 1) direct chip harvesting, 2) full-stem harvesting, and 3) a scenario with a guaranteed purchasing contract for fresh chip. Economic performance was considered using net present value over a 25-year plantation lifetime. The full-stem scenario provided the highest economic return over its lifetime with an average yearly net present value of £497 ha−1 (in £ sterling). This system was then considered for integration into a typical dairy farm, assuming 5 % land usage and including government grants for establishing riparian zones. The result was a drop in value of £28 ha−1 yr−1 compared to a dairy-only scenario; however, per litre of milk the farm employing willow coppice riparian buffer strips outperformed a typical dairy farm both environmentally and economically. Further analysis considered a novel approach that included payments for ecosystem services in the economic analysis. This analysis found that the implementation of government payments for ecosystem services (nutrient removal) increased the economic return of the willow coppice riparian buffer system by £400 ha−1 yr−1, resulting in minimal impact on the return from dairy land.This Bryden Centre project is supported by the European Union's INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPB). The views and opinions expressed in this paper do not necessarily reflect those of the European Commission or the Special EU Programmes Body (SEUPB). The work was also supported by Queen's University Belfast and the Agri-Food and Biosciences Institute in Northern Ireland. The authors would like to thank David Gilliland of Organic Resources and Alan Hegan of Hegan Biomass for the expert insight readily provided for this research
Consumer assessment, in Ireland and the United Kingdom, of the impact of the method of suspension of carcasses from dairy-origin bulls and steers, on the sensory characteristics of the longissimus muscle
No full textPublication history: Published online - 17 June 2023.The objective was to compare the assessment of beef produced in Ireland from a 19-month bull or a 24-month steer dairy beef production system by consumers in Ireland (Cork) and the United Kingdom (Belfast and Reading). Carcass sides were suspended by the Achilles tendon or by the pelvic bone and 21-d aged longissimus muscle assessed using Meat Standards Australia protocols. Carcass weight and classification were similar for bulls and steers. Consumers in Belfast and Cork rated aroma liking, tenderness, juiciness, overall liking and the composite meat quality score (MQ4) similarly, but lower (P < 0.05) than consumers in Reading. Consumers in Belfast and Cork rated flavour liking similarly as did consumers in Cork and Reading, but consumers in Reading rated flavour liking higher (P < 0.05) than consumers in Belfast. Muscle from steers had higher scores for aroma liking, flavour liking, overall liking and MQ4 scores than bulls (P < 0.05). On average, pelvic suspension increased (P < 0.05) the scores for aroma liking and flavour liking compared with conventional suspension but increased (P < 0.05) tenderness, juiciness, overall liking and MQ4 scores only in bulls. Consumers in Reading rated striploin from the traditional Achilles tendon-suspended steers similarly to striploin from pelvic-suspended bulls (MQ4 score of 71.8 and 68.2, respectively). Beef from the latter system could replace the traditional steer beef in this market, thereby benefiting the beef producer and the environment.The project was a part of the “Sensory Food Network Ireland” funded by the Irish Department of Agriculture, Food and the Marine Competitive research programmes (13/SN/401). The animal production portion was similarly funded (11/SF/322, BullBeef)
Planning and licensing for marine aquaculture
Get PDFPublication history: Accepted - 22 December 2022; Published online - 11 January 2023.Marine aquaculture has the potential to increase its contribution to the global food
system and provide valuable ecosystem services, but appropriate planning, licensing
and regulation systems must be in place to enable sustainable development. At present,
approaches vary considerably throughout the world, and several national and
regional investigations have highlighted the need for reforms if marine aquaculture is
to fulfil its potential. This article aims to map and evaluate the challenges of planning
and licensing for growth of sustainable marine aquaculture. Despite the range of species,
production systems and circumstances, this study found a number of common
themes in the literature; complicated and fragmented approaches to planning and
licensing, property rights and the licence to operate, competition for space and
marine spatial planning, emerging species and diversifying marine aquaculture production
(seaweed production, Integrated Multi-Trophic Aquaculture [IMTA], nutrient
and carbon offsetting with aquaculture, offshore aquaculture and co-location and
multiuse platforms), and the need to address knowledge gaps and use of decisionsupport
tools. Planning and licensing can be highly complicated, so the UK is used as
a case study to show more detailed examples that highlight the range of challenges
and uncertainty that industry, regulators and policymakers face across interacting
jurisdictions. There are many complexities, but this study shows that many countries
have undergone, or are undergoing, similar challenges, suggesting that lessons can be
learned by sharing knowledge and experiences, even across different species and
production systems, rather than having a more insular focus.Biotechnology and Biological Sciences Research Council; European Commission; Horizon 2020 Framework Programme, Grant/Award Numbers: GA 774426, GA 818173; Natural Environment Research Council; Norges Forskningsråd, Grant/Award Number: 29479