Bio: Joseph Cotton is an academic researcher from Bangor University. The author has contributed to research in topics: Bayesian statistics & Drought tolerance. The author has an hindex of 3, co-authored 4 publications receiving 45 citations.
17 Jul 2018
TL;DR: In this article, the authors assess potential methods for mitigating N losses from digestate applied to a winter wheat crop and subsequent impact on yield and N offtake in both grain and straw.
Abstract: The anaerobic digestion of food waste converts waste products into ‘green’ energy. Additionally, the secondary product from this process is a nutrient-rich digestate, which could provide a viable alternative to synthetically-produced fertilisers. However, like fertilisers, digestate applied to agricultural land can be susceptible to both ammonia (NH3) and nitrous oxide (N2O) losses, having negative environmental impacts, and reducing the amount of N available for crop uptake. Our main aim was to assess potential methods for mitigating N losses from digestate applied to a winter wheat crop and subsequent impact on yield. Plot trials experiments were conducted at two UK sites, England (North Wyke-NW) and Wales (Henfaes-HF), to assess NH3 and N2O losses, yield and N offtake following a single band-spread digestate application. Treatments examined were digestate (D), acidified-digestate (AD), digestate with the nitrification inhibitor DMPP (D+NI), AD with DMPP (AD+NI), and a zero-N control (C). Determination of N losses was conducted using wind tunnels for NH3, and static manual and automatic chambers for N2O. The N offtake in both grain and straw was also measured. Ammonium nitrate (NH4NO3) fertiliser N response plots (from 75 to 300 kg N ha−1) were included to compare yields with the organic N source. Across both sites, cCumulative NH3-N losses were 27.6 % from D and D+NI plots and 1.5 % for AD and AD+NI of the total N applied, a significant reduction of 95 % with acidification. Cumulative N2O losses, varied between 0.13 and 0.35 % of the total N applied and were reduced by 50 % with the use of DMPP although the differences were not significant. Grain yields for the digestate treatments were 7.52 – 9.21 and 7.23 – 9.23 t DM ha−1 at HF and NW, respectively. Yields were greater from the plots receiving acidified-digestate relative to the non-acidified treatments but the differences were not significant. The yields (as a function of the N applied with each treatment) obtained for the digestate treatments ranged between 84.2 % (D+NI) and 103.6 % (D) of the yields produced by the same N rate from an inorganic source at HF. Advanced processing of digestate
TL;DR: A Bayesian approach was used to calculate N2O emission factors (EFs) and their associated uncertainties from flux chamber measurements made after the application of nitrogen fertilisers at four grassland sites in the UK, indicating that more complex models may be needed, particularly for measurement data with high temporal resolution.
TL;DR: In this article, the agronomic, economic and environmental efficacy of three N-fertiliser sources, ammonium-nitrate (AN), urea (U), and inhibited-urea (IU; with NPBT), were evaluated at two grassland sites.
Abstract: Fertiliser nitrogen (N) is essential for maintaining agronomic outputs for our growing population. However, the societal, economic and environmental impacts of excess reactive N from fertiliser is rarely assessed. Here the agronomic, economic and environmental efficacy of three N-fertiliser sources, ammonium-nitrate (AN), urea (U), and inhibited-urea (IU; with NPBT) were evaluated at two grassland sites. Dry matter yield and herbage quality were measured at each silage-cut. Additionally, NH3-N and N2O-N losses were measured and used to calculate the effective N source cost and externality costs, which account for associated environmental and societal impacts. We found no effect of different N sources on yield or herbage quality. However, NH3-N emissions were significantly reduced under the IU treatment, by 48–65%. No significant differences in cumulative N2O emissions were observed. Incorporating externality costs increased fertiliser prices by 1.23–2.36, 6.51–16.4, and 3.17–4.17 times the origina...
TL;DR: In this paper, the role of red clover (cv. AberClaret) in minimising nitrogen (N) requirements, alongside two novel grass varieties, (1) a festulolium (v. AberNiche), developed for drought tolerance, with potential for deep-rooting, and (2) a ryegrass hybrid (CV. AberEcho) developed for high-sugar content, which may enhance ruminant N-uptake in vitro.
01 Nov 2019
TL;DR: A critical review of various technologies, with their updated progress, involved in the exploitation of MSW as a renewable resource, along with the critical advantages and limitations on energy and material cycling for sustainable MSW management is presented in this article.
Abstract: Municipal solid waste (MSW) management has emerged as probably the most pressing issue many governments nowadays are facing. Traditionally, Waste-to-Energy(WtE) is mostly associated with incineration, but now, with the emergence of the bioeconomy, it embraces a broader definition comprising any processing technique that can generate electricity/heat or produce a waste-derived fuel. Under the ambit of the circular economy many nations are looking for, additional effort must be made to be sure of acquiring the most updated information and paving a sustainable path for managing MSW in such a frame. In this regard, we have undertaken a critical review of various technologies, with their updated progress, involved in the exploitation of MSW as a renewable resource, along with the critical advantages and limitations on energy and material cycling for sustainable MSW management. Incineration, the most widely used method, is nowadays difficult to further apply due to its dubious reputation and social opposition. Meanwhile, to address the organic fraction of MSW which currently is mostly unrecycled and causes disposal issues, the biological approach presents an attractive option. The new emphasis of bioeconomy leads us to understand how environmental biotechnologies should be better connected/integrated for more sustainable MSW management. This article is concluded with advances of future prospects, which can serve as a timely reminder to encourage competent authorities/researchers to work towards further improvement of the present MSW management system.
TL;DR: Reduced nitrogen loss and high quality compost could be produced from food waste digestate by adapting mitigation strategies, and the nitrogen dynamics cycle considering high ammonium nitrogen content in the digestate is evaluated.
TL;DR: In this article, the authors reviewed the anaerobic digestion of food waste, the composition of its digestate and trends in the treatment of ADFE with emphasis on treatment using microalgae.
Abstract: Food waste constitutes a significant portion of waste in the world. Indeed, it is estimated that about one-third of edible human food is wasted globally. Anaerobic digestion has been identified as a promising technology for the treatment of food waste as it generates a significant amount of energy and can remove a substantial portion of the organics. However, this process has not been adequately applied due to technical and economic challenges. Most importantly, anaerobic digestion of food waste produces waste in the form of Anaerobic digestate food effluent (ADFE), with high amounts of nutrient such as ammonium (up to 3000 mg L−1 NH3-N). It has been established that this effluent can be used as a substrate for the cultivation of microalgae allowing both a means of its treatment and its possible valorization. This paper reviews the anaerobic digestion of food waste, the composition of its digestate and trends in the treatment of ADFE with emphasis on treatment using microalgae. Potential microalgal cultivation methods applicable to the treatment of anaerobic digestate, especially ADFE, and possible optimization of the cultivation methods are also reviewed critically. Further, understanding of the cultivation of microalgae in ADFE is required to aid in better design of its treatment process and valorization to improve its economics.
TL;DR: In this paper, the authors review strategies to improve management at each stage of the manure management chain and at different scales and propose a manure nutrient recommendation system that accounts for the range of manure types, cropping systems, soils and climates throughout China.
Abstract: As the demand for livestock products continues to increase in China, so too does the challenge of managing increasing quantities of manure. Urgent action is needed to control point source (housing, storage and processing) and diffuse (field application) pollution and improve the utilization of manure nutrients and organic matter. Here, we review strategies to improve management at each stage of the manure management chain and at different scales. Many strategies require infrastructure investment, e.g., for containment of all manure fractions. Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies. At the field-scale, there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types, cropping systems, soils and climates throughout China. At the regional scale, coordinated planning is necessary to promote recoupling of livestock and cropping systems, and reduce nutrient accumulation in regions with little available landbank, while minimizing the risk of pollution swapping from one region to another. A range of stakeholders are needed to support the step change and innovation required to improve manure management, reduce reliance on inorganic fertilizers, and generate new business opportunities.
TL;DR: In this paper, the authors presented the first long-term N2O eddy covariance dataset measured from a working farm, which was used over a four-year period to measure fluxes of the greenhouse gas nitrous oxide (N2O) from an intensively managed grazed grassland, to which regular applications of ammonium nitrate or urea fertilisers were spread, for two years each at the field site.