Organic farm incomes in England and Wales 1998/99

This report presents results from research work carried out for the Ministry of Agriculture, Fisheries and Food (MAFF) on the financial performance of organic farms in 1998/99. The aim of the research was to assess the financial performance of organic farms differentiated by farm type, in order to inform MAFF policy-making with respect to organic farming, and to provide a basis for assessments by farmers, advisers and other interested parties of the farm-level implications of conversion to and continued organic farming. To provide an idea of the trends over time, where possible data for continuous samples of farms are presented for 1997/98 and 1998/99. The specific objectives of this project OF0190 were to extend the previous project (OF0125, covering 1995/96 to 1997/98) to collect and collate data on the financial performance of organic farms, differentiated by farm type1. This was achieved through the collation of financial data collected under three different MAFF-funded research projects supplemented by data collected on other farm types. The samples of organic farms are small because of the limited number of organic holdings over 8 ESU (European Size Units) with identifiable holding numbers in 1996, when the previous study was started. As the sample is small there is limitation on how the results may be extrapolated to the wider population of organic farms, especially as the structure and objectives of those converting to organic production in the late 1990s may be different from those that converted in the 1970s and 1980s. Detailed financial input, output, income, liabilities and assets and some physical performance measures are presented for 1998/99. Where an identical sample of five farms is available, data are presented for 1997/98 and 1998/99 for the sample. The organic farm samples are so small that outliers (especially larger farms) have a large influence on the average. If the samples were larger, general trends would be more apparent and less influenced by individual farms; despite this, some explanation has been attempted of trends and changes in inputs, outputs and incomes. However, great care must be taken in extrapolating results. Of those farm types for which a continuous identical sample of five farms was available, Net Farm Incomes (NFI) increased for cropping (£281/ha) and dairy farms (£487/ha) in 1998/99 compared with 1997/98; in both cases outputs as well as inputs increased between years. Mixed farms showed an average reduction in outputs and increase in inputs, lowering the average NFI to £15/ha in 1998/99. The five lowland cattle and sheep farms improved a negative NFI of £161/ha in 1997/98 to a positive £7/ha in 1998/99 through an increase in livestock outputs with a similar level of inputs to that of 1997/98. Due to the high level of farmer and spouse labour on horticultural holdings, the average Management and Investment Income (MII) of the sample was negative, but the average NFI was £1,836/ha. On four holdings, 1998/99 average outputs were 92%, and inputs were 97% of the previous year, resulting in an average NFI in 1998/99 for that group of 75% of the 1997/98 result. The group of LFA farms, consisting of four cattle and sheep and one mixed farm, achieved an average NFI of £72/ha in 1998/99

Arsenic in the environment

Arsenic, long synonymous in people's mind with poison exhibits a varied, fascinating and dynamic biogeochemistry. Chemically and biologically reactive, its chemical form, or speciation, changes with slight variations in chemical or biological conditions. Depending upon the extent to which any arsenic containing system is dominated by physical/chemical or biological process, the forms of arsenic may change between the various in organic and methylated species, and may alter rapidly with varying conditions. Early research revolved around the formulation of pigments, and later in the development of effective medicines. Later still, thanks due to its long history as a poison, arsenic was included in numerous agricultural practices, mainly as a herbicide or pesticide. It has also seen service in the rather more specialised field of chemical warfare, and still poses threats as a result of improper disposal. Much of the recent research has focused on the identification of previously unknown organoarsenic species found in estuarine and marine waters. This work is building up an understanding of the biological pathways involved in the biochemical cycling of arsenic. Little work has been carried out with respect to the cycling of arsenic in freshwaters in comparison to that in marine and estuarine waters. Similarly, there has been less work performed on the speciation of arsenic in freshwater sediment interstitial waters, than there has on marine sediments, or intertidal sediments. The characterisation of arsenic in dynamic porewater poses a set of unusual and difficult problems, not the least being the procurement of representative, discrete samples. A number of potential sampling methods are reviewed, and variations on the thin film gel sampling technique are drought to provide perhaps the best option, although this will depend upon the type of intertidal sediment being investigated, and the information sought. It may be impossible to propose a general model of arsenic cycling either at a local scale or at a global level. This is of course due to the great diversity in ecosystems, each having different controls over arsenic speciation, and containing different biological communities. Once a given system has been described, the patterns of arsenic speciation (both spatially and temporally) are explainable, and potential impacts can be identified, but (hey cannot be transferred to another system. The continuing accumulation of information regarding arsenic speciation in different systems is helping in the unravelling of the larger global arsenic cycle. Such an understanding can only be a benefit in the development of safe and efficient remediation schemes for contaminated soil and aquatic systems

Studies in pianistic sonority, nuance and expression: French performance practices in the piano works of Maurice Ravel

This thesis traces the development of Maurice Ravel’s pianism in relation to sonority, nuance and expression by addressing four main areas of research that have remained largely unexplored within Ravel scholarship: the origins of Ravel’s pianism and influences to which he was exposed during his formative training; his exploration of innovative pianistic techniques with particular reference to thumb deployment; his activities as performer and teacher, and role in defining a performance tradition for his piano works; his place in the French pianistic canon. Identifying the main research questions addressed in this study, an Introduction outlines the dissertation content, explains the criteria and objectives for the performance component (Public Recital) and concludes with a literature review. Chapter 1 explores the pianistic techniques Ravel acquired during his formative training, and considers how his study of specific works from the nineteenth-century piano repertory shaped and influenced his compositional style and pianism. Chapter 2 discusses Ravel’s implementation of his idiosyncratic ‘strangler’ thumbs as articulators of melodic, harmonic, rhythmic and textural material in selected piano works. Ravel’s role in defining a performance tradition for his piano works as disseminated to succeeding generations of pianists is addressed in Chapter 3, while Chapters 4 and 5 evaluate Ravel’s impact upon twentieth-century French pianism through considering how leading French piano pedagogues and performers responded to his trailblazing piano techniques. It will be shown that through his activities as teacher and performer, as well as composer, Ravel took control of every detail pertaining to his piano works with his meticulously notated scores, piano roll recordings and interpretive guidance imparted to other pianists, thus catalysing performance practices that promulgated a distinctively French twentieth-century pianistic tradition

Combined stable isotope and gut contents analysis of food webs in plant-dominated, shallow lakes

1. To determine feeding links between primary producers, invertebrates and fish, stable isotope analyses and gut content analyses of fish were conducted on the components of four shallow, eutrophic to hypertrophic, plant-dominated lakes. 2. Although separation of basal resources was possible, the diets of both fish and invertebrates were broad, comprising food from different compartments (planktonic, epiphytic/benthic), as well as from different trophic levels. 3. Mixing models were used to determine the extent to which periphyton production supported higher trophic levels. Only one species of invertebrate relied upon periphyton production exclusively. 4. Fish density affected the diets of invertebrates. The response was different for planktonic and epiphytic/benthic invertebrates. The proportion of periphyton production in the diets of zooplankton appeared to increase with fish density, whilst it decreased for other invertebrates. 5. As all zooplankton samples were collected in the open water at dusk, these results are further evidence for the diurnal horizontal migration of zooplankton. Although not conclusive, they are consistent with a behavioural response by invertebrates and zooplankton in the presence of fish

High frequency environmental DNA metabarcoding provides rapid and effective monitoring of fish community dynamics

Long‐term monitoring is critical to measure the response of biodiversity patterns and processes to human‐mediated environmental pressures. This is particularly pertinent in freshwaters, where recent estimates indicated a third of all fish species are threatened with extinction, making ongoing biomonitoring essential for conservation management. High frequency annual monitoring is critical for identifying temporal changes in fish community composition; however, traditional survey methods are typically less practical over such timeframes. While environmental (e)DNA measurement represents a potentially powerful tool for monitoring temporal community dynamics, studies are lacking. To address this deficit, we generated a high frequency time‐series dataset of entire fish communities using eDNA metabarcoding, to directly assess the repeatability and sensitivity of this method for detecting annual population trends. We targeted two differing environments (freshwater vs. intertidal) within the Thames catchment, UK, where detailed historical records from traditional monitoring were available for comparison. To test how robust eDNA data is for inferring the known community, we applied a hierarchical, nested design encompassing short and longer‐term variation in eDNA data. Our analyses showed that irrespective of environment, eDNA metabarcoding represented known seasonal shifts in fish communities, where increased relative read abundance of eDNA coincided with known migratory and spawning events, including those of the critically endangered native species Anguilla anguilla (European eel). eDNA species detections across a single year included over 75% of species recorded in a ca. 30‐year historical dataset, highlighting the power of eDNA for species detection. Our findings provide greater insight into the utility of eDNA metabarcoding for recovering temporal trends in fish communities from dynamic freshwater systems and insight into the potential best sampling strategy for future eDNA surveys

Physical and biological controls on fine sediment transport and storage in rivers

Excess fine sediment, comprising particles <2 mm in diameter, is a major cause of ecological degradation in rivers. The erosion of fine sediment from terrestrial or aquatic sources, its delivery to the river, and its storage and transport in the fluvial environment are controlled by a complex interplay of physical, biological and anthropogenic factors. Whilst the physical controls exerted on fine sediment dynamics are relatively well-documented, the role of biological processes and their interactions with hydraulic and physico-chemical phenomena has been largely overlooked. The activities of biota, from primary producers to predators, exert strong controls on fine sediment deposition, infiltration and resuspension. For example, extracellular polymeric substances (EPS) associated with biofilms increase deposition and decrease resuspension. In lower energy rivers, aquatic macrophyte growth and senescence are intimately linked to sediment retention and loss, whereas riparian trees are dominant ecosystem engineers in high energy systems. Fish and invertebrates also have profound effects on fine sediment dynamics through activities that drive both particle deposition and erosion depending on species composition and abiotic conditions. The functional traits of species present will determine not only these biotic effects but also the responses of river ecosystems to excess fine sediment. We discuss which traits are involved and put them into context with spatial processes that occur throughout the river network. Whilst strides towards better understanding of the impacts of excess fine sediment have been made, further progress to identify the most effective management approaches is urgently required through close communication between authorities and scientists

Transformation of an uncertain video search pipeline to a sketch-based visual analytics loop

Traditional sketch-based image or video search systems rely on machine learning concepts as their core technology. However, in many applications, machine learning alone is impractical since videos may not be semantically annotated sufficiently, there may be a lack of suitable training data, and the search requirements of the user may frequently change for different tasks. In this work, we develop a visual analytics systems that overcomes the shortcomings of the traditional approach. We make use of a sketch-based interface to enable users to specify search requirement in a flexible manner without depending on semantic annotation. We employ active machine learning to train different analytical models for different types of search requirements. We use visualization to facilitate knowledge discovery at the different stages of visual analytics. This includes visualizing the parameter space of the trained model, visualizing the search space to support interactive browsing, visualizing candidature search results to support rapid interaction for active learning while minimizing watching videos, and visualizing aggregated information of the search results. We demonstrate the system for searching spatiotemporal attributes from sports video to identify key instances of the team and player performance. © 1995-2012 IEEE