Data Envelopment Analysis (DEA) is a well-established relative efficiency measurement technique, which has been widely applied to evaluate the technical efficiency of agricultural units in different countries by focusing on different aspects of agricultural production. This research deals with the evaluation of efficiency through DEA in non-homogeneous agricultural production, where units produce a wide range of different outputs. The objectives are threefold. Firstly, we propose a novel methodological approach of integrating the production trade-offs concept of DEA into non-homogeneous agricultural efficiency evaluation to prevent the overstatement of the efficiency of specialist farms and overcome the issue of insufficient discrimination due to large number of outputs in the models. Secondly, we aim to integrate this methodological perspective to the theory of elasticity measurement on DEA frontiers. The efficient frontiers of DEA are not defined in functional forms as in the classical economic theory, therefore obtaining elasticity measures on them require different considerations. We introduce the production trade-offs to the elasticity measurement and derive the necessary models to calculate the elasticities of response in the presence of production trade-offs. As a third objective, before moving to the introduction of the trade-offs in elasticity measurement, for theoretical completeness, we first consider the elasticity measurement on DEA frontiers of constant returns-to-scale (CRS) technologies. Our proposed methodology and all the developed elasticity theory are illustrated in a real world case of Turkish agricultural sectors. We provide extensive empirical applications covering all the proposed theory and methodology. Among the results of this research, we provide an elasticity measurement framework, which enables us to calculate elasticities of response measures in both VRS and CRS technologies, with or without production tradeoffs included. We observe that the integration of production trade-offs provide better discrimination of efficiency scores compared to the models without trade-offs included. We also investigate how changing production trade-offs affect the efficiency and elasticity measures of the evaluated units.

This thesis is a product of a case study on how innovation transfer affects women‘s participation in cowpea production in two communities in northern Ghana. The study addresses issues relating to how gender relations modify technological development, impact upon innovation transfer, dissemination and adoption among local farmers and how they affect the inclusion of women in agricultural development programmes. The context of the research is the growing awareness of the importance of involving women in agricultural development programmes. This change has occurred due to the realisation of women‘s key contribution to the agricultural sector and the need to focus technological development on both men and women. The thesis draws upon primary data produced during 12 months fieldwork in northern Ghana. This fieldwork utilised three research tools: interviews, observations and focus group discussions. Data for the interviews was collected by purposive sampling and included 65 male and female cowpea farmers, living in three villages. In addition, seven observations were undertaken in two villages and focusing on their cowpea storage practices. Finally, eight staff from The Savanna Agricultural Research Institute, The Ministry of Food and Agriculture and World Vision Ghana were also interviewed in order to gain the views and perspectives of agricultural development agencies. It is argued here that that gender equality is crucial for effective agricultural development because women are hugely involved in the agricultural sector. It is also argued that if women‘s role in ensuring effective development of cowpea production is not taken into account, the consequences will not only affect the lives of women but will also have negative consequences for the communities in which they live. Debates in technological advancement in the agricultural sector indicate that the participation of farmers in the processes of innovation development and diffusion enhances innovation adoption. The thesis argues that the development of agricultural innovations is not based on a comprehensive analysis of gender roles and as a result does not offer equal opportunities for women and men to participate and benefit. It offers further explanations on how the national agricultural development agencies are working around to actively involve both men and women in the processes of innovation development and transfer. Furthermore, the thesis argues that, notwithstanding farmers‘ interest in new and improved agricultural innovations, they are most likely to incorporate their traditional norms and values when using new or improved agricultural innovations. Thus it offers insights on how new innovations that bear similarities to older ones, are widely adopted.

The aim of this thesis is to investigate the factors controlling the spread and distribution of bracken (Pteridium aquilinum) in Scotland. Bracken has long been an agricultural problem and, more recently, fears have been raised about the plant's carcinogenic properties. Despite the seriousness of the problem, there has been little quantitative research into factors controlling the plant's vigour, although there are many anecdotal references on the subject. It is the aim of this thesis to; study the climatic, edaphic and biotic characteristics of the bracken zone; establish the statistical relationship between these factors and bracken vigour and to apply the findings to explain how these factors affect bracken in Scotland. The climatic, soil, vegetation and biotic characteristics of four sites in the bracken zone (west, south-west, north-east and south-east) are reviewed first. By comparisons of inter-site factors and bracken vigour at the sites, it is possible to formulate hypotheses on the factors that control bracken vigour. Correlation and regression analyses of individual factors with frond height, density and litter depth are than carried out, followed by a Stepwise Regression Analysis. Finally the findings of the two sections are summarised and the results applied to explain bracken distribution and spread in Scotland. The major conclusions of this thesis can be summarised as follows: Early season temperature strongly affects bracken vigour and largely accounts for the east-west difference in bracken vigour. Vigorous bracken in the west can withstand a greater degree of frosting than the less vigorous bracken in the east. Soil moisture stress, heavy frost and relatively intensive agriculture in the east results in a higher bracken zone (and therefore suboptimal soils and temperatures) in the east than in the west.

A fruit and vegetable-rich diet has been associated with decreased risk of developing chronic diseases such as cardiovascular disease and cancer in humans. These protective effects have been attributed in part, to the presence of phytochemicals in fruit and vegetables, in particular flavonoids and phenolic compounds. Some plants have been used in traditional medicine for healing, ritual ceremonies and as health tonics or food supplements. Recent interest in the health-promoting properties of Malaysian traditional vegetables has been based on claims about their uses in health and medicine. However, scientific information to support these claims is largely unexplored. The overall objectives of the present study were to investigate, determine and quantify the phytochemicals, particularly phenolic compounds, in the seven samples from five species of selected Malaysian traditional vegetables (Anacardium occidentale, Centella asiatica, Colubrina asiatica, Pluchea indica and Premna cordifolia) and to evaluate their activities in vitro, including antioxidant and antibacterial activities of extracts of these plants and individual phytochemicals. In the first section of this project, discussed in Chapter 3, Malaysian traditional vegetable extracts were screened for phenolic compounds using several complimentary techniques, namely high performance liquid chromatography (HPLC) and HPLC-tandem mass spectrometry and the total phenolic content determined using the Folin-Ciocalteu assay. Flavonol glycosides were predominant in most of the species, particularly A. occidentale with levels ranging from 6434 to 12420 µg/g fresh weight. Chlorogenic acids were the main components identified and quantified in C. asiatica and P. indica. The total phenolic content of the vegetables were between 100 ± 7.8 and 415 ± 20 mg/ kg gallic acid equivalent (GAE) in batch 1 but lower in batch 2 ranging from 62 ± 2.5 to 386 ± 41 mg/ kg GAE. The total phenolic content of plant extracts was positively correlated with total antioxidant capacity, determined by 2, 2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric reducing antioxidant potential (FRAP) assays. A. occidentale exhibited the highest total phenolic content and total antioxidant activity, whereas Colubrina asiatica, which had the lowest total phenolic content, also had low antioxidant activity in vitro. Phenolic content and antioxidant activity were significantly (p<0.05) influenced by environmental factors, as in this study, plant materials in batch 1 which was harvested in rainy season, had a higher total phenolic and antioxidant content than batch 2, which was harvested in the dry season. Based on the hypothesis that other components in addition to phenolics also contributed to the total antioxidant activities in the plants, the next objective, which was presented in Chapter 4, was to investigate the occurrence of phytochemicals such as triterpenes, carotenoids, α-tocopherol and vitamin C. The level of total triterpenes, biomarkers of C. asiatica was not significantly different between batches. The main component was madecassoside with 91 ± 4.8 µg/g fresh weight in batch 1 and 77 ± 3.4 µg/g fresh weight in batch 2. The level of carotenoids and vitamin C were low compared to previous reports. This was almost certainly due to dried samples being used in the present study, as some of the compounds would have broken down during drying process. This would have particularly affected the levels of vitamin C, which contributed only 0.9 to 5.5% to the total antioxidant activity of the plants under study. Total antioxidant activities of plant essential oils were determined using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and the result was in agreement to the total antioxidant activities of plant extracts, which A. occidentale having the highest amount. The highest antioxidant activity exhibited by A. occidentale oil was attributed to the presence of high amounts of γ-terpinene (28%) and terpinen-4-ol (4.2%), both of which were shown to have strong radical scavenging activity. The high phenolic content, antioxidant activity and occurrence of volatile components exhibited by A. occidentale has led to the final objective of this study, which is presented in Chapter 5. This was to screen for antimicrobial activities of A. occidentale extracts and essential oil against selection of Gram-positive (Enterococcus faecalis, Staphylococcus aureus, Meticillin-resistance Staphylococcus aureus (MRSA), coagulase negative Staphylococci (CoNS) and Lactobacillus acidophilus), Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) and fungi (Candida albican) using disc diffusion and minimum inhibitory concentration (MIC) methods. Investigation of the modes of action was determined using growth inhibition curve, scanning (SEM) and transmission (TEM) electron microscopy. A. occidentale was shown to have promising effects at 25 mg/ml with regard to inhibiting the growth of Gram-positive bacteria including MRSA. The essential oil and its major component, γ-terpinene at only 2.5% (v/v) inhibited the growth of all Gram-positive and Gram-negative bacteria. None of the A. occidentale extracts or oil exhibited antibacterial activities against Lactobacillus acidophilus, an important strain of bacteria found in the human gut. This indicates selective effects of A. occidentale. A. occidentale extract and oil inhibited the growth of S. aureus cells within a 2-hour incubation observed in time-kill experiments. SEM and TEM examination revealed that the oil and its component, γ-terpinene, inhibited the bacteria through bacteriostatic and bactericidal effects which damaged the bacterial cell wall. Testing the oil and γ-terpinene against epidemic-MRSA (EMRSA) biofilms indicated an anti-adhesive effect, which disrupted the bacterial colonies in the biofilms to produce more extracellular polysaccharides (EPS). The effects of A. occidentale oil were comparable with tea tree oil, a widely used topical antiseptic. All the Malaysian traditional vegetables under study are claimed to have medicinal properties and health effects. The results in the present study have provided some information on phytochemical and nutritional properties of Malaysian traditional vegetables, and as a consequence provide a sound scientific base for promoting their consumption particularly in Malaysia.

Biofumigation is being increasing used as alternative control method for soil borne pathogens. This method exploits toxic compounds, specifically isothiocyanates (ITCs), which are released during the breakdown of Brassica plant tissues. To date field and glasshouse experimentation assessing the potential for using biofumigation to control agricultural pests and pathogens have produced promising results. Yet large gaps still remain in the specifics of the biofumigation process. It is hoped that further research to analyse how specific toxic compounds produced during Brassica tissue breakdown, specifically ITCs, affect different pathogens. Additionally analysis of the specific isothiocyanates and concentrations produced by Brassica spp. will allow a more pathogen targeted approach to biofumigation to be generated. The importance of assessing the biofumigation process on different scales is also understood, and therefore this study has encompassed work carried out in vitro and using glasshouse experimentation to establish a comprehensive overview of the biofumigation process. Assessing the effects different agricultural treatments have on soil microbial communities has also been recognised and therefore was also be investigated in this study. This study aimed to determine the effects isothiocyanates, produced by Brassica spp., have on three economically important soil borne fungal pathogens, Colletotrichum coccodes, Rhizoctonia solani and Helminthosporium solani. Initial assessment was carried out using in vitro bioassays, allowing assessment of the overall toxicity of each ITC. Results identified that the pathogen response was dependent on both the structure of the ITC and the concentration of ITC present. The most significant pathogen suppression was observed with R. solani when exposed with benzyl or methyl ITC and H. solani when exposed to 2-phenylethyl ITC. To gain understanding of the naturally produced ITCs Gas-Chromatography Mass-Spectrometry analysis was used to analyse specific isothiocyanates produced by a range of different Brassica spp., at different development stages. Results identified Allyl, Benzyl and 2-Phenylthyl ITC as the most commonly produced by the Brassica cultivars used within this study. Overall the Allyl was found within the highest concentrations; however the specific ITCs and concentrations produced were dependent on both the development time and cultivar. Glasshouse experimentation was also carried out to assess both the effects of pure ITCs on R. solani and C. coccodes fungal inoculum within compost and diversity changes within the soil microbial community, in response to isothiocyanate incorporation and the biofumigation process. In order to examine changes in microbial communities‟ analysis was carried out using Terminal Restriction Fragment Length Polymorphism, a DNA fingerprinting method which allows bacterial diversity shift to be traced and statistically analysed. Overall incoproation of pure ITCs did not significantly reduce black scurf or black dot disease symptoms on daughter potato tubers. Additionally after 30 days soil microbial community diversity was not greatly altered by the addition of ITCs. Therefore as it is often suggested that biofumigation is influenced by the soil activity it is thought that this may be due to the addition of Brassica tissue. The increase of organic matter into agricultural soils may influence both biological and chemical processes which may in turn aid pathogen suppression. Overall this study provides a detailed insight into establishing the specific interactions that occur during biofumigation. Results produced findings of ITCs which significantly suppressed the growth of fungal potato pathogens. Development of a novel GC-MS assay revealed previously unknown data of levels and profiles produced by a number of different Brassica plants. Additionally study was also carried out to evaluate the effects of biofumigation of soil microbial communities, which is often ignored within other studies. Overall this study aimed to gain an increased level of knowledge of such processes in order for the methods and the results presented, to be used to establish effective, pathogen targeted biofumigation systems.

Ammonia is the most prevalent alkaline gas in the atmosphere and plays an important role in environmental pollution through acidification and eutrophication. Livestock are the largest source of ammonia in the UK, mainly originating during storage and spreading of animal manure. The aim of this study was to validate the collection efficiency of recurved passive ammonia flux (PAF) samplers and the flux frame method to provide a robust methodology for measurement of distributed agricultural sources of ammonia outdoors. The collection efficiency of recurved PAF samplers was determined in a wind tunnel under controlled conditions of ammonia flux (0.771 - 13.49 mg NH3 m-2 s-1), and at angles of orientation to the flow direction (0, 30, 60, 70, 80, 90°). The samplers were effective up to a wind speed of 7 m s-1 and an angle of 80°, with a mean collection efficiency of 71%. The flux frame method had a mean collection efficiency of 87.4% when used with ground level point sources under controlled conditions in the Atmospheric Flow Laboratory. However, in controlled field releases, the efficiency fell to 56.4%. The flux frame method was also suitable for line sources, although assumptions must be made about the source homogeneity and plume dispersion. ADMS modelling was used to predict the collection efficiencies for the flux frame method and these agreed with measured collection efficiencies to within 37.3%. A comparison of source strengths determined using a full size flux frame and portions of the flux frame showed that a full size flux frame was unnecessary as one column of samplers produced a very similar estimate to that of the whole frame. The validated method was then used to measure ammonia emissions from free-range pigs. The amount of ammonia emitted from this source was very low and less than 0.16 g (kg of sow)-1 day-1.

Relic periglacial solifluction features cover most of Britain, particularly the Midlands and the South, causing serious and continuing earthwork and construction problems. Although the engineering significance of the presence of periglacial solifluction deposits is widely appreciated, the mechanics of emplacement of these deposits has received surprisingly little attention. The principal objective of the research has been to investigate the freeze-thaw behaviour of some clay soils in Britain which have been exposed to periglacial conditions. The behaviour was examined using a Permafrost Oedometer or Permode, based on the apparatus used by Morgenstern and Smith, (1973). Tests have been carried out on Lias Clay, Weald Clay and Oxford Clay. In each test, a specimen was placed under an applied stress and subjected to 24 hour cycles of freezing and thawing. Freezing was mainly imposed from the top of the specimen downwards. The tests were carried out undrained. The pore water pressures were found to increase as a result of cyclic freeze-thaw conditions. Greater pore water pressures were generally recorded at the top than at the base of the specimen. This was considered to be due to moisture migration towards the freezing front during freezing, and impeded filtration, (due to underlying frozen material), during thaw. The significance of the additional pore water pressures in terms of slope stability was considered. A semi-infinite slope analysis model was used primarily, but reference was made to other, similar research. The analysis found that the predicted slope angle of failure is reduced significantly by relatively low increases in pore water pressure. Greater increases in pore water pressure are gained for soils of lower residual shear strength/higher plasticity. It was determined that the generation of excess pore water pressure and corresponding decrease in residual strength have considerable implications for the stability of slopes previously exposed to periglacial conditions.

Many authors have blamed African land tenure systems for the poor agricultural production and environmental degradation in sub-Saharan Africa, and therefore the resulting hunger, environmental refugees and the lack of socio-economic progress. The aim of this investigation was to investigate the customary and statutory tenure practices in north-east Ghana and their implications for agricultural production and environmental degradation and recommend ways of improving tenurial practices. The study revealed that contrary to the mainstream view that lack of security of customary land tenure is the main cause of the poor agricultural production and environmental degradation, stakeholders’ perceptions of their security of tenure was generally high. Stakeholders’ religious background, gender, levels of education, age, occupation and community membership status were important factors influencing their perceptions and attitudes to land tenure, and land and environmental management practices. Yet poor agricultural production and environmental degradation characterised the study area. Interviewees perceived the main causes to be due to non-tenurial factors including lack of finance, poor soil fertility, inadequate and unreliable rainfall, pests and diseases, inadequate farmlands, bush burning and excessive tree cutting. It was also shown in the study that women and strangers generally had little or no power and control over land use decision-making and management under customary land tenure. These findings have negative implications for tenurial conditions, environmental and livelihood sustainability in north-east Ghana since most women are involved in food production. Results of the investigation were used to develop a participatory and holistic approach to land use and management and developed an integrated framework of customary and statutory tenure as a way forward in sustainable land management and the provision of sustainable livelihoods in north-east Ghana in particular, and sub-Saharan Africa generally. The study has contributed to an understanding of the political ecology of north-east Ghana and concludes that the emerging changes in land resource access and use have conflicts as an inevitable element of the process, which broad-based stakeholder participation provides a useful solution.

This thesis focussed on assessing smallholder groundnut farmers and traders’ access to markets through quality improvement and also, determine the socio-economic factors that influence groundnut farmers when deciding to adopt quality management techniques and the extent/or level of involvement. The following research questions were tested: whether Malawi smallholder groundnut farmers have poor or limited access to markets; whether smallholder farmers face unequal bargaining relations with traders due perhaps to lack of competition in trading channels; whether belonging to a farmer organisation provides a framework whereby the prospects of higher prices could lead to higher quality regulated by the association? Qualitative analysis was used to map out the main processes, key actors and relationships within the various groundnut value chains. Price spread method was used to assess market efficiency in price for the various groundnut market channels. Finally, a Selective Tobit model was used to assess factors that influence smallholder farmers to adopt technologies on quality management and decide the extent of adoption. The study results indicated that smallholder farmers manage to sell all their groundnuts brought to the market. This means that smallholder farmers do not really have problems accessing the markets. However, there is a limited availability of structured groundnut markets that offer premium price as an incentive for farmers to invest in quality management. Another important finding is that belonging to an organised farmer organisation enabled smallholder farmers to access better agricultural services such as research, extension and quality certified seed. However, it was not enough to persuade the farmers to venture into collective marketing. The results suggest that the provision of economic incentives such as premium prices persuaded farmers to engage in collective action and also invest in quality management. There is convergence of prices for less quality sensitive regional markets and quality sensitive EU markets. As such, exporters have no incentive to invest more in quality management targeting EU markets. Selective Tobit model results showed that farmers value most profitability-related variables such as land allocated, structured markets and prices when deciding level of involvement in quality management. The study results also indicate that groundnut market in Malawi is efficient in price as demonstrated by the Market Efficiency Index of greater than one. Gross margin analysis also indicated that, on average, groundnuts producers have good returns to labour if compared to the current national minimum wage rate of US$1.2 per day.

Phytoremediation is a green technique used to restore polluted sites through plant-initiated biochemical processes. Its effectiveness, however, depends on the successful establishment of plants in the contaminated soil. Soils that are contaminated with polycyclic aromatic hydrocarbons (PAHs), especially low molecular weight, mobile PAHs such as naphthalene pose a significant challenge to this. Plant roots growing in these soils exhibit changes to their structure, physiology and growth patterns. Tall fescue (Festuca arundinacea) roots grown in sand contaminated with either petroleum crude oil (10.8g total extractable hydrocarbons kg-1 sand dw) or naphthalene (0.8g kg-1 sand dw) exhibited a temporary inhibition in elongation with accelerated lateral growth (p<0.01), whilst also showing a deviation from the normal root orientation responses to gravity. Scanning electron micrographs (SEM) revealed that the stele in the contaminated roots was located much further away from the root epidermis, because the cortex was larger (p<0.001) due to the cells being more isodiametric in shape. Once past the initial acclimatisation period of 2.5-3.0 months, no visual differences were observed between control and treated plants, but the root ultrastructural modifications persisted. The fluorescent hydrophobic probe „Nile red‟ was applied to the epidermis of a living root to mimic and visualise the uptake of naphthalene into the root through the transpiration stream. The root sections were also stained with 0.1% (w/v) berberine hemisulphate in order to stain Casparian bands. Overlaying images obtained with the use of Texas red HYQ filter (wavelength 589-615nm) and UV illumination (wavelength 345-458nm) revealed the presence of passage cells in the endodermis and uptake of Nile red into protoxylem vessels beyond the endodermis of control roots. On the other hand, the path of Nile red was blocked at the endodermis of naphthalene- treated roots. The cell walls in the endodermis of naphthalene-treated roots were prominently thickened (p<0.001) and lacked passage cells. The treated roots also possessed a well-formed exodermis (p<0.01). The results suggest that the well-formed endodermis lacking passage cells, the well-formed exodermis as well as the increased cortex zone provided an effective barrier to the flux of hydrophobic xenobiotics towards the inner core of the roots, if previously exposed to the contaminants. The SEM images of naphthalene-treated as well as crude oil-treated roots showed partial collapse in the cortex zone, presumably due to water stress, but the treated plants withstood drought stress better than the control plants. The underlying physiological changes responsible for the adaptive responses of tall fescue to the exposure to naphthalene contamination were studied through metabolic profiling of plant roots and shoots. The results indicated synergistic interactions between sugars or sugar- like compounds and phenolic compounds may assist to create an integrated redox system and contribute to stress tolerance in naphthalene-treated tall fescue. The signal for a compound speculated to be indole acetic acid (IAA) was either subdued or absent in the tissues of naphthalene-treated tall fescue, suggesting the existence of a detoxification mechanism/ defence pathway in the treated plants. The ultra-structural and molecular modifications, resulting from PAH stress enabled tall fescue to resist tougher challenges.