The provision of crops of a light fry colour, from store, is of the utmost importance to processors. Poor fry colour leads to rejection of crops on a quality basis. The application of Chlorpropham (CIPC) sprout suppressant, as a thermal fog is associated with a deterioration in fry colour. The BPC funded project at the University of Glasgow and its collaborator Sutton Bridge Experimental Unit investigates the effects of CIPC use on the processing quality of stored potatoes. CIPC is the only sprout suppressant available for medium and long-term storage for processing in Britain. In the UK the majority of CIPC treatments are conducted as thermal fog applications. This is considered to be the most practical means of achieving successful sprout control. The introduction of a hot fog into potato stores has a disruptive influence. It can physiologically alter the potatoes by creating a stressful environment. Tuber respiration rate increases and so the crop will age. Experimental trials conducted as part of this project have shown that it is the fogging process itself that is responsible for the decrease in crop quality following application, not the CIPC formulation applied. Studies revealed that both carbon dioxide and ethylene were produced naturally by crop and from the combustion of petrol used to generate thermal fogs. Initially the fry colour problems were linked with carbon dioxide in combustion gases and from increased respiration. However, carbon dioxide output from thermal fogger machines was less significant than expected. The levels were consistently lower than concentrations shown to have a deleterious effect in previous BPC funded work. Ethylene is present in thermal fogs as a by-product of burning the hydrocarbon fuel used to generate fog. The concentration of ethylene produced is associated with the running conditions of the fogger machine I.e. burner temperature, type and volume of fuel used etc. The ethylene created in a standard CIPC thermal-fog application is sufficient to induce a physiological response in tubers. Exposure of crop to ethylene effects respiration, dormancy period, sprout morphology, reducing sugar concentration and hence fry colour. The extent of the outcome depends on exposure time and concentration. Following assessment of the fogging situation, various means of reducing the impact of CIPC application on fry colour were evaluated. Different approaches were undertaken and included both attempting to control and remove the contaminants present in thermal fogs. By ventilating stores earlier than the recommended twenty-four hour period after treatment a vast improvement in fry colour was observed. In doing this the exposure time of crop to contaminants was greatly reduced. In the experimental work the stores were ventilated eight hours after treatment. This allowed adequate time for the effective fraction of the thermal god to settle.

No description available.

This thesis examines the role and use of indigenous knowledge within small-scale agricultural systems in Africa and its relevance in development practice and theory. Using development programmes that have been implemented in the study area from the colonial to the recent times, many of which were largely underpinned by modernisation theory and practice, indigenous knowledge theory and practice is analysed for its role in development processes. The roles of the private sector, NGOs and the government are analysed, based on a chronology of development programmes that were underpinned in many instances by the influences of the major development theories and the subsequent introduction of the structural adjustment programmes by the IMF and the World Bank. Particular emphasis is placed on farmers’ responses to externally induced development programmes, designed by experts for farmers to adopt. In their assessment of these externally driven development programmes, there is a manifestation of the extent of the resilience of local knowledge to its displacement by Western knowledge. Scientifically proven technologies are assessed by farmers for their effectiveness under their farming practices that take into account a range of environmental, socio-cultural and economic factors. Indigenous knowledge is frequently found to be effective in resisting those changes that are undesirable and of little relevance at both farm and community levels. For farmers, knowledge that is useful and of practical use is adopted, or adapted, only when it is assessed, and, in many cases, this is only after trials have been successfully completed. Knowledge that is of little benefit to farmers is discarded irrespective of its type (indigenous or Western), or its source. This study forms the basis for understanding the importance of indigenous knowledge in development practice arising from its existence at farm level and the fact that it is continuously being fined-tuned to suit specific conditions and situations, which are in turn affected by socio-cultural, economic and environmental factors. The findings of this study also show that there are many benefits from using indigenous knowledge in development practice that include the empowerment of local people through their participation in development programmes. Indigenous knowledge is also found to be resilient and beneficial to farmers regardless of income level by reducing their costs of production, to be adaptable to different environmental and economic circumstances, and to provide for a more sustainable use of resources in farming. There is, however, a need for further studies in indigenous knowledge utilisation to enable researchers to keep pace with changes that occur at the local level if development theory and practice are to utilise indigenous knowledge fully and successfully.

The thesis consists of a study of chlorpropham distribution patterns and its behaviour within tuber components in commercial potato stores in the UK. The store examined were both cold (3-4 °C) and conventional (8-10 °C) stores. As a large number of samples from different stores were taken, it was important to have a quick and reliable analytical method for chlorpropham determination. This was developed and compared against the original accepted method. Both methods were more or less similar in their precision of results, with recoveries of 83.80 2.25 and 93.14 3.51 from spiked samples by blending and reflux extracting methods respectively. When the methods were compared for extracting the amount of chlorpropham in commercially treated stored samples, it gave recoveries of 2.49 0.25 and 2.58 0.17 for the blending and reflux methods respectively. Overall the reflux extracting method was quicker and easier and it was used for further work with some slight modification. The present study showed that the level and distribution pattern of chlorpropham was significantly different within the store and as well as between different commercial stores. The overall range of chlorpropham levels in the examined stores was 2.11-236.56 mg/kg. The amount of chlorpropham varied with respect to sampling sites of the examined stores. Each store has its own distribution pattern with some similarities. However there was a common trending all the stores examined in that the maximum level of chlorpropham was on the top surface and minimum on the lower levels of the stores. In the cold store examined 'A' ( 3-4 °C) the level of chlorpropham decreased continuously from the top height towards the bottom height of the store. However the amount of chlorpropham was excessive throughout the store, even in the middle of the boxes it exceeded the MRL (Maximum Recommended Level). The level of chlorpropham dropped from 128.39 mg/kg in the middle layer samples of the top box to 49.14, 20.15, 19.01, 8.03 3.97 and 4.54 mg/kg towards the bottom boxes of a six high column of boxes in the store respectively.

Initial experiments performed in this study allowed species differentiation of Globodera pallida and G. rostochiensis following immunoblotting with the lectin, wheat germ agglutinin (WGA), and the monoclonal antibody TEPC 15. Further studies were aimed at the isolation of amphidial secretions. Two methods of collecting secretions were attempted, one involving the modification of a previously described staining method, the other relying on the collection of ES products from living, sterile nematodes. Secretions collected from G. pallida using the two different methods were analysed using SDS-PAGE electrophoresis. Secretions were also used for anti-serum production, giving two anti-sera, Luffness anti-serum and ES anti-serum. These were subsequently used for immunoblotting and indirect immunofluorescence studies. Indirect immunofluorescence studies indicated that the two anti-sera recognised different nematode components. This was further confirmed by immunoblotting studies which revealed that Luffness anti-serum recognised a number of nematode proteins, and was capable of differentiating both between and with species of G. pallida and G. rostochiensis. In contrast, ES anti-serum recognised only two proteins which appeared to be conserved between the two species. Observations also indicated that presence of a nematode lectin component present in amphidial secretions with apparent specificity for N-acetylgalactosamine. Experiments were also performed to examine different methods of inducing secretions. Previous research (Goverse et al., 1994) has shown that the serotonin agonist 5-methoxy dimethyl tryptamine (DMT) is an effective inducer of nematode oesophageal secretions. Comparison of DMT-induced secretions with ES secretions using SDS-PAGE electrophoresis revealed that the protein profiles were similar, although some proteins were more abundant following induction with DMT. Treatment of G. pallida with DMT followed by indirect immunofluorescence with Luffness anti-serum revealed an increased and altered distribution of antibody binding on the nematode surface.

This thesis is concerned with the following studies : 1- Ammonium analysis in soil and water including the determination of low levels of ammonium (<0.1 mg N/1) in groundwater and the colorimetric analysis of highly coloured groundwater samples. 2- An investigation of groundwater quality and soils at a contaminated industrial site. 3- Bioremediation treatment of the ammonium and nitrate contaminated groundwater using natural soil and vegetation and using soil incubation and pot experiments. These findings of a pot experiment suggest the possibility of applying the bioremediation treatment of the ammonium and nitrate contaminated water in the field. A field study should be undertaken to evaluate the efficiency of this bioremediation treatment. This field study would require a suitable uniform area to lay out the plots, preferably close to the source of water to be used. In addition, it is necessary to carry out a hydrological survey to determine the following aspects: 1-The size of groundwater reservoir. 2-The rate of removal of the water. 3-The time scale of the water application. The climatic conditions such as rainfall, potential evapotranspiration and temperature should be taken into consideration when carrying out the bioremediation treatment in the field as these climatic conditions affect the water requirements and the growth of grass. There are three options to apply the contaminated groundwater as follows : 1-To apply the contaminated groundwater at low or high volume depending on its level of nitrogen. 2-To blend well water with high level of nitrogen with well water with low level of nitrogen to achieve a realistic irrigation rate at a suitable nitrogen level. 3-To overirrigate in expectation that ammonium would be retained in the soil. The ryegrass used in this bioremediation treatment can be disposed of by incineration and landfilling the ash or landfilling the grass.

The research undertaken was designed to investigate the potential use of coppice woodland for the clean up and remediation of heavy metal contaminated soil. Particular attention was given to high yielding coppice woodland species, especially willow and poplar. This was because breeding and field trials have reported that some hybrid willow clones can produce biomass yields of up to 60 t ha-1 y-1. The experimental works undertaken comprised three experiments which have been referred to as the 'Field Studies', 'Pot Studies' and 'Hydroponic Studies' and describes the medium in which the trees were grown and studied. The experiments were devised to study the variation in the uptake of metals between different tree species growing in different environments. The findings of the studies generally indicate that metal uptake rates determined in the field were lower that the uptake levels recorded in the pot and hydroponic studies. These differences were attributed to the increased availability of the study metals in the pot and hydroponic studies. Zinc concentrations in the above ground tissue of willow determined from the three experiments ranged from 159 to 223 mg kg-1 in the field study, 281 to 2995mg kg-1 in the pot study and 40 to 5530 mg kg-1 in the hydroponic study. Zinc was the only metal accumulated to significant concentration within the biomass of fields samples. Zinc, copper, cadmium, nickel and chromium were accumulated in the biomass of seedlings grown in the pot studies and zinc, copper, cadmium, nickel, chromium and to a lesser extent lead were accumulated by some of the hydroponic study trees. Some of the uptake levels recorded were not dissimilar from accumulation levels reported in hyperaccumulater species and highlights the potential of some tree species to accumulate metals in above ground tissues (leaves, twigs and stem). The pot and hydroponic studies suffered high seedling fatality rates which were attributed to metal toxicity and/or salinity. These findings could indicate possible establishment problems when trying to plant trees on contaminated sites.

Aspects of the biology, epidemiology and control of Rhizoctonia solani from potato were investigated using a range of laboratory and field-based experiments. In vitro experiments revealed nutritional factors including a range of carbon sources, and inorganic and organic nitrogen did not affect significantly mycelial growth or sclerotial germination. Carbon and nitrogen sources including cellobiose, glucose, glycerol and potassium nitrate significantly increased sclerotial biomass production in vitro. Mycelial growth, sclerotial production and germination occurred over a temperature range of 10-30oC, with an optimum of 25oC for both AG 2-1 and AG 3 isolates. Mycelial growth and sclerotial germination occurred at pH 4-9 with an optimum of pH 5.6, whereas sclerotial production occurred between pH 4-6 for AG 2-1 isolates and pH 4-8 for AG 3 isolates. Mycelial growth, sclerotial biomass production and germination declined with decreasing osmotic, matric and soil water potential, with mycelial growth prevented between -3.5 MPa and -4.0MPa on osmotically adjusted media, at -2.0 MPa on metrically adjusted media and -6.3 MPa in soil. Sclerotial production ceased prior to the limits for mycelial growth and germination for all isolates, between -1.5 MPa and -3.5 MPa on osmotically adjusted media and -1.5 MPa on metrically adjusted media. AG 3 isolates produced significantly more well-formed sclerotia during all in vitro experiments compared to the loosely constructed sclerotia produced by AG 2-1 isolates. A pathogenicity bioassay, coupled with staining and microscopic examination of stem tissues, showed all AGs formed infection cushions as a prerequisite to infection, with clear differences in the extent of infection cushion formation and subsequent stem lesion severity. AG 2-1 produced small, infrequent infection cushions, causing stem lesions only 1-2 mm in length which did not increase in size or severity after initial formation.

Most of the fieldwork for this study was conducted on the island of Islay, in the Inner Hebrides, the stronghold of the chough, Pyrrhocorax pyrrhocorax L., in Scotland. The aims of this study were to provide baseline data on the phenology of potential invertebrate foods of the chough, and to provide a greater understanding of the factors affecting these invertebrate populations. The literature concerning (a) the chough in Britain and its feeding ecology, (b) the invertebrate fauna of pasture, (c) the invertebrates associated with cow dung, (d) ivermectin and its effect on the invertebrate fauna associated with cattle dung, and (e) the multivariate analysis methods used in this study, is reviewed. An area of heather moorland and four pastures were selected on Islay. Invertebrates were collected from these sites between January 1988 and November 1989 using pitfall traps, and by sampling soil and cow pats. The data obtained was analysed using two multivariate analysis methods -Two-Way-Indicator-Species- Analysis (TWINSPAN) and Detrended Correspondence Analysis (DECORANA). Information on 62 surface-active taxa was obtained from pitfall trapping. Although seasonal taxa assemblages were recognized, the distribution of the invertebrate communities was primarily related to soil moisture content. Grazing intensity and seasonality were also important factors determining the composition of the invertebrate fauna at each site. The taxa active during the summer and winter at the two sand grassland sites, did not appear to differ as markedly as at the other sites sampled. Figures showing the seasonal activity of some of the frequently occurring taxa at each site considered potential chough prey items are provided. Surface-active potential chough food items were present, at all the sites investigated, throughout the year. Soil-sampling provided information on 34 taxa. As with the surface-active fauna, the primary factor influencing the soil fauna was soil moisture content. The time of year was also an important factor governing the soil fauna composition, with the majority of taxa occurring in low numbers during the summer months at all the sites sampled. Figures indicating the seasonal occurrences of some of the taxa considered potential chough prey items at each site are provided. Soil did not appear to be a good source of potential prey items for the chough during the summer months, although, as a result of seasonal increases in size, certain taxa, e.g. Tipulidae larvae, may have been more 'worthwhile' prey items at this time of year than at any other. Information on 54 taxa was obtained from sampling cow dung. Seasonality and age of the dung were very important in determining the composition of the dung fauna. The seasonal variations in the fauna associated with the cow pats are described. Potential chough prey items were associated with cow dung, in any stage of decay, throughout most of the year. Only during the period from October/November to January did there appear to be a lack of suitably sized potential prey items in the dung. The 'summer' months, when fresh dung contained large numbers of beetle adults and developing fly larvae, and late autumn, when pats deposited during the summer months are old enough for the large numbers of Aphodius spp. larvae present to have attained a reasonable size, were considered to be the times at which cow dung presented the best feeding opportunities for the chough. Fifty taxa were identified in samples of chough faeces. Multivariate analysis of these data indicated that the seasonal availability of prey items was the most important factor influencing chough diet throughout the year. Soil-dwelling Tipulidae (January to July) and Bibionidae (January to April) larvae, dung-associated insects (during the spring, and late summer and autumn), and surface-active insects (during the summer) were important invertebrate components of the diet. Cereal grains were extremely important supplementary food items during the early winter months, when invertebrate availability was low. An experiment was conducted at the College to investigate the effects on the dung fauna of spiking cow dung with 2.0, 1.0, or 0.5 mg/kg dung of ivermectin. Pats were placed on pasture between May and September 1988. The pats were lifted, and the soil beneath sampled, after 15 to 90 days exposure. A total of 65 taxa were identified. These data were analysed using TWINSPAN, DECORANA and Canonical Correspondence Analysis (CANOCO). The major factors determining the invertebrate fauna of the pats were length of exposure, exposure date, and ivermectin presence/absence. Ivermectin markedly affected the fauna associated with the pats. Pats exposed in June and August degraded faster than those exposed in May or September. In June, the ivermectin-treated pats degraded significantly slower than the control pats. An attempt to extract ivermectin from cow dung for analysis by high-performance liquid chromatography is described. This proved unsuccessful and the reasons for this failure, and possible improvements, are discussed. The main conclusions of this study are: (1) that Tipulidae larvae are extremely important components of the chough's diet on Islay, and that the climatic conditions of the island favour these insects; (2) livestock farming on Islay, especially the out-wintering of cattle, provides essential feeding opportunities for the chough, as, (a) gazing animals produce the short sward preferred by the chough as a feeding habitat, (b) large numbers of insects are associated with the dung of these animals, and (c) supplementary feed provided for the cattle in winter also provides an essential alternative food source for the chough at a critical time; (3) the chough's preference on Islay for feeding in sandy, coastal pasture is due to the fact that these sites, (a) contain a variety of suitable invertebrate prey items throughout most of the year, (b) are normally intensively grazed and so contain large amounts of dung with its associated fauna, and (c) are used for out-wintering cattle and therefore cereal grains can be found there; (4) treating cattle with ivermectin could have an adverse effect on the chough as it reduces the number and variety of invertebrates associated with the dung, an important food source for the birds, especially in spring and autumn.

One of the greatest proximate threats facing biodiversity is habitat change as a result of the combined effects of agricultural development and livestock grazing. Extensive livestock systems are increasingly competing with wildlife for access to land and natural resources in African rangelands. Ethiopia has the highest numbers of livestock in Africa with most livestock production taking place in highland systems. The Bale Mountains contain the largest extent of afroalpine habitat in Africa and are the most important conservation area in Ethiopia as one of thirty-four Conservation International Biodiversity Hotspots. The Bale Mountains National Park was established forty years ago to protect the endemic, and rodent-specialist Ethiopian wolf (Canis simensis) and the afroalpine habitats upon which they depend. I use a 21 year time-series of livestock counts in the park to detect changes in the Oromo traditional livestock production system or godantu. I show that a seasonal transhumant livestock production regime, akin to godantu, only appears to persist in the Web valley today and I also find some evidence that the type of livestock is changing with smaller stock, such as sheep and goats, being more frequently kept. Despite reportedly growing numbers of households in the Web valley, I do not detect an overall increase in livestock numbers, suggesting that the area may have reached its carrying capacity in terms of livestock. In contrast, the number of livestock on the Sanetti Plateau increased over the monitoring period, including the remote and inhospitable western section of the plateau. Furthermore, I detect an increase in the risk of contact and disease transmission between Ethiopian wolves and free-roaming dogs in wolf optimal habitats. I subsequently estimate, through the use of transects, the densities of livestock in the Web valley, Morebawa and Sanetti and calculate the ratio of observed to maximum sustainable livestock density (based on rainfall and vegetation productivity). The conservative results suggest that the Web valley and Morebawa are overstocked given the rangeland predicted productivity for those areas, and that the problem of overstocking is at its worst during the dry season. I then establish critical relationships between vegetation conditions, livestock grazing pressure and rodent populations (Tachyoryctes macrocephalus, Lophuromys melanonyx and Arvicanthis blicki) in the afroalpine, under both natural and controlled experimental conditions. Rodent biomass declines as the livestock index increases along a natural grazing gradient, but rodents‟ body condition, use of the habitat or breeding ecology and most vegetation variables measured do not significantly vary across the livestock grazing gradient. Rodent populations do respond to the experimental removal of livestock inside exclosures, although this response is site and species-specific, and I find some evidence that these responses are concurrent with changes in the vegetation. Grazed plots have higher plant species richness and diversity compared to the exclosure sites which harbour reduced bareground cover and taller vegetation. Differences among rodent species in their responses to grazing may be mediated by interaction between the direct effects of grazing on habitat quality and species-specific habitat requirements, although the specific mechanism of this interaction could not be tested. Livestock may negatively affect rodents by increasing their predation risk (through removing vegetation cover), by reducing the soil suitability for maintaining burrow systems (through trampling) or, less likely, by competing for food resources. A series of simple dynamic food chain models are developed to explore the interactions between Ethiopian wolves, rodents and vegetation and how they may be affected by increasing levels of livestock grazing. I also explore how predictions made about these trophic dynamics are affected by the type of functional response linking the different levels. The models suggest that the pastures of the Web valley and Morebawa are likely to be incapable of maintaining wolves at current livestock densities, while the Sanetti plateau may be able to sustain only slight increases in livestock density before tipping into a trophic configuration unable to sustain wolves. This model is a first step in assessing the seriousness of conflict between pastoralists and wildlife in BMNP. Resource selection functions are developed and validated for cattle and sheep/goats grazing in the Bale afroalpine in an attempt to understand some of the drivers behind the heterogeneous use of the landscape by livestock. Habitat use by livestock is focused on lower-lying pastures in the vicinity of water sources (rivers or mineral springs). Only cattle strongly select for/against particular vegetation types. The probability of habitat use is also linked to the distance from the nearest villages. The models developed highlight a strong association between livestock use and rodent biomass in Morebawa and Eastern Sanetti, suggesting that livestock grazing poses a threat to Ethiopian wolves‟ persistence in marginal habitats in which rodent availability is already limited. Furthermore, the concentration of livestock around water sources has serious implications for the degradation of the park‟s hydrological system and the livelihoods and food security of the millions of people living in the dependent lowlands. Integrating research and practice is a fundamental challenge for conservation. I discuss how the methodological tools developed and the insights gained into the dynamics of the afroalpine system can contribute to the management of livestock grazing pressure in Bale Mountains National Park and highlight gaps in the knowledge of the afroalpine ecosystem where more research is needed.