No description available.

No description available.

An evaluation and comparison of the flow of geochemicals through three systems of farm management is made, using Vicia faha L. as a crop phytometer. Organic manures form the only nutrient addition to one system (Organic), artificial fertilizers alone are applied to the second (Stockless), and the third system receives a mixture of the two nutrient sources (Mixed). The influence of the farm management upon each of the main components of the agricultural ecosystem is determined, and these are discussed separately in the five main sections of the text. Crude balance sheets are constructed to demonstrate the magnitude of the annual flow of geochemicals through each system. -The soil of the three farms is compared by chemical analysis. It is shown that where organic manures have been used, the content of available plant nutrients is significantly higher than in the soils where only inorganic fertilizers have been applied. The flow of water through the ecosystem is determined by the use of lysimeters. A study of the chemical composition of the leachate shows that the system receiving both manures and fertilizers provides the greatest threat of eutrophication. The maximum loss of plant nutrients from the soil is shown to occur during the season of the greatest rainfall. The rate of the fixation of energy into the system is determined by a study of the growth and yield of the crop phytometer. It is found that the long-term practice of growing separate stocks of seed on each farm, (imprinting), does not cause any physiological evolution to occur by which each plant type could become better suited to its own farm type. It is demonstrated that, the magnitude of the growth of the bean plants does not show any significant effect of farm management, despite the differences in nutrient availability from the three soils. It is suggested that this lack of growth response is due to the high background level of nutrients in all the soils. The only effect of nutrient availability is shown by the size of the bean seed yield, but this effect is seen to be drastically modified by weed competition. The flow of geochemicals into the standing crop is investigated by detailed chemical analysis of the plants throughout the season. Corresponding to the lack of growth response to the farm management, no significant effect of soil treatment can be shown to be influencing the chemical composition of the crop. There is no evidence to show any eutrophication of the crop by nitrates, but a marked death reaction is demonstrated to be causing high concentrations of lead in the bean seeds. Due to a greater biomass on the Mixed section, it was this management which incurred the greatest flow of geochemicals into the standing crop. The phenomenon of symbiotic nitrogen fixation by the phytometer is investigated. A close relationship between the rate of fixation, the extent of nodulation and the availability of soil nitrogen is determined. The former two characteristics are show to provide an accurate assay of the level of nitrogen in the soil. Calculation of the probable annual fixation of nitrogen shows that this is maximal on the farm where no organic manures are supplied. From the construction of the balance sheets, and the discussion in the text, it is indicated that the management system, which is the most geo- chemically and economically viable, is the Mixed system. This farm produces the highest yield of bean seeds, and permits a reasonable level of nitrogen fixation by the legume, but also poses the most serious threat of eutrophication to other ecosystems. Even so, the concentration of nitrates in the leachate never exceeded the maximum safe limit suggested by the World Health Organization.

No description available.

Preservation of quality is the primary consideration in the drying of grass seed. Quality may be lost through destruction of seed viability and contamination by mould. Both result from the establishment, within the drying bed, of undesirable temperature and moisture conditions generated by the interaction of the seed and drying air. The work was based on the assumption that such moisture and temperature changes could be calculated from a knowledge of the heat and mass transfer properties of the seed and air, and that it would be possible to proceed from this physical framework to the calculation and imposition of biological restraints upon the selection of drying conditions. Experimental work was carried out with a large and a small seeded strain of ryegrass of similar shape and structure. For each strain, potential germination was expressed as a function of moisture content at threshing. Apparatus was developed for determining exposed layer drying curves at a wide range of air conditions and numerical procedures were developed for fitting the data to alternative diffusion equations. The fitted constants were expressed as functions of drying air temperature, humidity and seed initial moisture content. Effects on germination were expressed as functions of drying air temperature, exposure time and potential germination. A mathematical model of the drying process was programmed in FORTRAN and used the exposed layer constants to predict moisture and temperature changes in deep beds subjected to fluctuating inlet air conditions. The model was stable, economical in computing time and gave reasonable overall agreement with experimental deep bed results. Consistent over-cptimism of the. drying time predictions was identified with cumulative error in temperature changes. Possible revisions of the basic equations pose problems of integration beyond the scope of the present work.

The primary aim of the programme of research described in this thesis was to develop a method of calculating the pressures of ensiled materials for use in the design of silos. I have given in Chapter I the detailed records of the filling and unloading of a number of silos. Chapter 2 includes a literature survey and, the results of-my own field work on'the measurement of pressures wall strains and silage temperatures. Chapter 3 is concerned with the measurement of the properties of concrete silo staves and proposes quality standards, Chapter 4 reviews in detail the available information on the physical and biological properties of ensiled grain including my research on the varilations in grain density with pressure, moisture content and time. Chapter 5 similarily reviews the data on the, properties of ensiled grass and forage, including my research on the densities of these materials under the wide variety of conditions encountered in silos, I have used the results of my field and laboratory work and published material to develop in Chapter 6 a finite lamina calculation method for determining the pressures in and the capacities of silos, This enables the field conditions (with wide varlations in the maturity and moisture content of layers) to be simulated in detail and the optimum filling technique to be calculated. It also enables the filling rate required to limit overheating for given crop conditions to be determined.

This research has been carried out by the author at the Materials and Engineering Research Institute at Sheffield Hallam University in collaboration with Chapmans Agricultural Ltd. Abrasive wear is a significant issue in many industries but is of particular significance in agriculture. This research is being carried out due to the demand for a hard wearing, economical coating for use in the agricultural industry. A primary objective has been to review and develop an in depth understanding of the type of wear suffered by metal shares in agricultural soils. The affect of soil properties and abrasive wear environments on the amount of wear that occurs, and the way in which material properties can be used to reduce or prevent this has also been investigated. A review of the diverse range of soil properties, such as the mineral content, moisture content, soils strengths has been carried out in order to create an appropriate wear test procedure. The coatings developed for testing were modifications to an existing powder metallurgy coating. The modifications were made by the addition of selected hard phases to the powder prior to sintering. The resulting materials were characterised in terms of sinterability, hardness and abrasive wear resistance. Prior to commencing this work little or no data existed on the wear performance of the pre-existing coating. Wear resistance has been measured using a fixed ball micro-scale abrasive wear test (also known as the ball-cratering wear test) with SiC and SiO2 abrasives and also using a modified version of the ASTM G65 abrasive wear test which allowed testing in dry and wet modes. Limited field trials were performed to determine the abrasive wear resistance in real soil. Results from wear testing have determined that the optimum modification to the coating can improve performance compared to the unmodified coating. Detailed scanning electron microscopy (SEM) has been performed on the wear scars and has revealed the resultant wear mechanisms and role that the hard phase additions play in improving the wear resistance. The influence of the hard phase addition on the microstructure has also been studied. The wear volume and corresponding wear coefficient from laboratory studies have been used to determine the optimum level of addition that can be added to produce an improved wear resistance. The results show the optimum hard phase addition to be 100μm WC/WZC particles at around IOwt.% with 15 μm WC at 5wt.% also providing improved wear resistance.

Pesticides are widely used in agriculture to control weeds, pests and diseases. Successful control is dependent on the compound reaching the target site within the organism after spray or soil application. This is influenced by a range of physiological and environmental factors. One such factor is uptake into foliar tissue and roots and subsequent movement through the plant. Uptake and translocation (and metabolism) can affect the speed and persistence of action, crop selectivity and weed spectrum, thus understanding these issues is of great importance. Conventional methods for determining uptake and movement of herbicides and pesticides include autoradiography, liquid scintillation and chromatographic techniques such as HPLC. Autoradiography using radiolabelled compounds provides the best indication of a compound's movement within the plant system which is an established technique but relies on radiochemical synthesis. The cost and time taken means that only a relatively few agrochemicals can be studied in this way. MALDI is a highly adaptable soft ionisation technique that was established in the late 1980's through the developmental research of Tanaka and Hillenkamp. The versatility of MALDI-MS has been extended in recent years with the advent of protein profiling and imaging directly from the surface of thin biological tissue sections. Research by Caprioli et al has resulted in the successful profiling and imaging of proteins from thin sections of healthy mouse brain and mouse brain containing tumor and the profiling of proteins from a neurotoxin induced rat modelof Parkinson's disease. Recently the imaging technique has been further developed by research groups to include the detection and imaging of small organic molecules on the surface of porcine epidermal tissue and the surface of rodent brain tissue. In preliminary studies undertaken to support the grant application for this project the detection and imaging of compounds on the surface of a plant leaf or inside a plant stem using MALDI-MS was demonstrated. In this project the technique of imaging matrix assisted laser desorption ionisation mass spectrometry has been used to examine the uptake and distribution of a range of compounds of agrochemical interest into growing plants. The agrochemicals of interest are azoxystrobin, mesotrione, fluazifop-p butyl and nicosulfuron. Azoxystrobin is a broad spectrum fungicide which inhibits mitochondrial respiration in fungi; the compound is absorbed through the roots and translocated in the xylem. Mesotrione is a selective phloem mobile herbicide which inhibits HPPD, an enzyme involved in carotene synthesis and results in bleaching of the leaves. Fluazifop-p butyl is absorbed as its ester, which is quickly hydrolysised to its carboxylic acid (fluazifop acid) that is mobile in the xylem and the phloem. Fluazifop acid works as a fatty acid synthesis inhibitor, by inhibition of acetyl CoA carboxylase (ACCase). Nicosulfuron is both xylem- and phloem-mobile which inhibits branched chain amino acid synthesis by means of the acetolactate synthase (ALS) enzyme. MALDI-MS images of mesotrione in tissue underlying the waxy cuticle layer following removal using a tape stripping method have been generated. MALDI-MS images have been generated from azoxystrobin following uptake via the roots in soya and sunflower plants. Nicosulfuron translocation following uptake via the0roots and foliar application has been determined in sunflowers and a phase I metabolite has been identified 48 hours following uptake via the roots and 24 hours following foliar application using MALDI-MSI. Nicosulfuron and azoxystrobin translocation has been determined in the same plant following application of the compounds to the plant stem. The methods developed were used to determine the extent of translocation of four sulfonylurea herbicides 24 hours following foliar application. Additionally, a preliminary method was assessed to determine whether MALDI-MSI can be used to assess translocation of agrochemicals.

Problems faced by UK farmers formed the raison d'etre for this research. Agriculture plays an important role in the UK economy. However, due to difficulties securing the necessary workforce, problems associated with hiring migrant labourers, and competition from cheap imported produce, the UK's Gross Value Added (GVA) plummeted from £9.8 to £5.2 billion in the decade leading up to 2005. As a result, the automation of certain farming (and horticultural) jobs is becoming a desirable alternative to man-power, in an aim to re-establish the supply and demand for local and exported produce. The need for low-cost, robust and manoeuvrable robots to attract farmers' interest in agricultural/horticultural automation was met by the introduction of Ransomes Jacobsen's Spider®, a grass cutting mower that could be converted into an autonomous robot. With the appropriate transformation in hardware and computer software, it has provided the opportunity for such research.

The Lothians of Scotland are generally farmed intensively, with arable farming predominating in the more easterly regions. Potatoes form an integral part of the cropping pat- tern with sugar beets and turnips somewhat less widely grown. Wheat and barley are the principal cereal crops. Grass is in- cluded in the rotation on practically every farm. The returns from cropping are usually complemented by returns from the production of beef cattle. Farmers of the area usually have one or more beef cattle enterprises, frequently with emphasis on fattening cattle for slaughter. The farming pattern, with emphasis on potato production, requires a substantial labour force, measured on an "acres per man" basis, as compared to less intensively farmed areas such as the unirrigated portions of Alberta. The availability of this labour force during non -critical seasons might be expect- ed to result in a level of mechanization differing from that developed for less intensively farmed areas. For field work, a larger number of smaller capacity machines might be expected, and for cattle feeding a lower level of mechanization might be expected. Despite these expectations there is a keen interest in highly mechanized processes. This is particularly evident in processes associated with cattle production. This intensive, well integrated pattern of agriculture offers a challenging application for linear programming as a management aid. In addition, the interaction between cropping practise, manpower availability, and level of mechanization, particularly with respect to beef cattle feeding, offers an excellent medium for the extension of linear programming into the fixed -cost sector of farm business. Tabulated, the objectives of the research leading to the preparation of this thesis were to: 1) Investigate the application of linear programming as an aid to farm planning in the Lothians. 2) Complementary to this objective, to assess the availability and suitability of Scottish agri- culture research data for the preparation of linear programmes. 3) The development of extensions to linear programming to permit the analysis of any mechanized activity in full economic association with other farm activities. 4) An investigation of the use of linear programming, with extensions, as a method for determining the optimum levels of mechanization for beef cattle feeding.