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Dave Chadwick

Bio: Dave Chadwick is an academic researcher from Bangor University. The author has contributed to research in topics: Digestate & Greenhouse gas. The author has an hindex of 12, co-authored 33 publications receiving 991 citations. Previous affiliations of Dave Chadwick include Southwest University & Rothamsted Research.

Papers
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Journal ArticleDOI
TL;DR: McAllister et al. as mentioned in this paper reviewed the current understanding of how manure management influences direct and indirect N 2 O emissions and CH 4 emissions, introduce new data comparing direct N 2O emissions following spreading of a range of manure types by different methods, and highlight some of the mitigations being considered by researchers and policy makers in developed and developing countries.

485 citations

Journal ArticleDOI
TL;DR: Benefits of cover crops justify their widespread adoption, but management practices in relation to cover crops will need to be adapted to specific soil, management and regional climatic conditions.
Abstract: Cover crops play an increasingly important role in improving soil quality, reducing agricultural inputs and improving environmental sustainability. The main objectives of this critical global review and systematic analysis were to assess cover crop practices in the context of their impacts on nitrogen leaching, net greenhouse gas balances (NGHGB) and crop productivity. Only studies that investigated the impacts of cover crops and measured one or a combination of nitrogen leaching, soil organic carbon (SOC), nitrous oxide (N2 O), grain yield and nitrogen in grain of primary crop, and had a control treatment were included in the analysis. Long-term studies were uncommon, with most data coming from studies lasting 2-3 years. The literature search resulted in 106 studies carried out at 372 sites and covering different countries, climatic zones and management. Our analysis demonstrates that cover crops significantly (p 0.05) effects on direct N2 O emissions. Cover crops could mitigate the NGHGB by 2.06 ± 2.10 Mg CO2 -eq ha-1 year-1 . One of the potential disadvantages of cover crops identified was the reduction in grain yield of the primary crop by ≈4%, compared to the control treatment. This drawback could be avoided by selecting mixed cover crops with a range of legumes and non-legumes, which increased the yield by ≈13%. These advantages of cover crops justify their widespread adoption. However, management practices in relation to cover crops will need to be adapted to specific soil, management and regional climatic conditions.

284 citations

Journal ArticleDOI
14 Sep 2018
TL;DR: This study argues that high-yield farming impacts should be measured per unit of production and shows that viewed this way, some land-efficient systems have less impact than lower-yielding alternatives, and suggests that trade-offs among key cost metrics are not as ubiquitous as sometimes perceived.
Abstract: How we manage farming and food systems to meet rising demand is pivotal to the future of biodiversity Extensive field data suggest that impacts on wild populations would be greatly reduced through boosting yields on existing farmland so as to spare remaining natural habitats High-yield farming raises other concerns because expressed per unit area it can generate high levels of externalities such as greenhouse gas emissions and nutrient losses However, such metrics underestimate the overall impacts of lower-yield systems Here we develop a framework that instead compares externality and land costs per unit production We apply this framework to diverse data sets that describe the externalities of four major farm sectors and reveal that, rather than involving trade-offs, the externality and land costs of alternative production systems can covary positively: per unit production, land-efficient systems often produce lower externalities For greenhouse gas emissions, these associations become more strongly positive once forgone sequestration is included Our conclusions are limited: remarkably few studies report externalities alongside yields; many important externalities and farming systems are inadequately measured; and realizing the environmental benefits of high-yield systems typically requires additional measures to limit farmland expansion Nevertheless, our results suggest that trade-offs among key cost metrics are not as ubiquitous as sometimes perceived

168 citations

Book ChapterDOI
TL;DR: An overview of compost quality standards in Europe, China, and the United States of America is given in this article, including a characterization of the plant residues, livestock manure, and organic wastes that can be composted.
Abstract: Organic wastes are composted to stabilize organic matter, reduce the moisture content, increase the concentrations of plant nutrients, eliminate pathogens and weed seeds, develop disease suppressiveness, and reduce greenhouse gas emissions. The requirements for compost quality depend on its final destination, which includes agriculture, horticulture, and urban landscaping. The development of a market for compost greatly depends on the definition and adoption of quality standards. Several countries and public and private organizations have established quality standards for compost, where certain properties are prioritized and different limits are established according to the end use. However, there is a need to harmonize such criteria at the international level. Also, if the process of composting is not managed properly, then it can result in excessive emissions of ammonia (NH3), nitrous oxide (N2O), and methane (CH4). This review compares compost quality criteria across different countries, addresses strategies for reducing the environmental impacts of composting processes, and evaluates new analytical and microbiological approaches to define compost quality. An overview of compost quality standards in Europe, China, and the United States of America is given, including a characterization of the plant residues, livestock manure, and organic wastes that can be composted.

153 citations

Journal ArticleDOI
TL;DR: The environmental balance of the UK biogas sector for the years 2014 and 2017 is evaluated, with policies to encourage digestion of food waste and manures could maximize GHG abatement and covering digestate stores could largely mitigate net eutrophication and acidification burdens.

98 citations


Cited by
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Journal ArticleDOI
TL;DR: A forum to review, analyze and stimulate the development, testing and implementation of mitigation and adaptation strategies at regional, national and global scales as mentioned in this paper, which contributes to real-time policy analysis and development as national and international policies and agreements are discussed.
Abstract: ▶ Addresses a wide range of timely environment, economic and energy topics ▶ A forum to review, analyze and stimulate the development, testing and implementation of mitigation and adaptation strategies at regional, national and global scales ▶ Contributes to real-time policy analysis and development as national and international policies and agreements are discussed and promulgated ▶ 94% of authors who answered a survey reported that they would definitely publish or probably publish in the journal again

2,587 citations

Journal ArticleDOI
07 Apr 2016-Nature
TL;DR: ‘state of the art’ soil greenhouse gas research is highlighted, mitigation practices and potentials are summarized, gaps in data and understanding are identified and ways to close such gaps are suggested through new research, technology and collaboration.
Abstract: Soils are integral to the function of all terrestrial ecosystems and to food and fibre production. An overlooked aspect of soils is their potential to mitigate greenhouse gas emissions. Although proven practices exist, the implementation of soil-based greenhouse gas mitigation activities are at an early stage and accurately quantifying emissions and reductions remains a substantial challenge. Emerging research and information technology developments provide the potential for a broader inclusion of soils in greenhouse gas policies. Here we highlight 'state of the art' soil greenhouse gas research, summarize mitigation practices and potentials, identify gaps in data and understanding and suggest ways to close such gaps through new research, technology and collaboration.

1,221 citations

01 Jan 2011
TL;DR: In this paper, the authors present a survey of the estimated costs of soil erosion, an issue of fundamental importance in view of the current worldwide discussion on soil erosion. But the authors focus on the cost of soil degradation.
Abstract: Resumen en: The aim of this study was a survey of the estimated costs of soil erosion, an issue of fundamental importance in view of the current worldwide discussion...

983 citations

Journal ArticleDOI
TL;DR: In this paper, the potential for climate change mitigation through soil carbon sequestration that is possible from a change to no-till agriculture has been widely overstated, arguing that the potential of climate adaptation through carbon sequestering is limited.
Abstract: No-till agriculture is generally considered good for soils, and probably also beneficial in relation to climate change adaptation. However, this Perspective argues that the potential for climate change mitigation through soil carbon sequestration that is possible from a change to no-till agriculture has been widely overstated.

616 citations