Foliar urea was applied as a source of late-N between flag leaf emergence and anthesis to winter wheat crops that had received varying rates of basal-N fertilizer in the spring in order to produce crops with differently sized GAI). The crops grown were: no N fertilizer applied (NO), conventionally fertilized (Net), a Canopy Managed crop grown to a GAI 5 (GAI 5), at IACR-Rothamsted in 1995, with the addition of a GAI 3 crop (GAI 3) at IACR-Rothamsted in 1994 and at Sutton Bonington in 1995. Each of the applications of late-N as foliar urea resulted in the prolongation of GAI of Canopy Managed crops, irrespective of the timing, amount of N applied, or whether adjuvants were used. The date of complete death of canopy green area was similar for all foliar urea treatments due to the sunny, warm, dry weather at the end of July in both 1994 and 1995, at both sites. The duration of canopy green area was associated with its N content at anthesis, as well as with water availability and the prevailing weather conditions, such that Ncf crops, containing significantly more N than GAI 5 crops at anthesis, retained green area for a longer period than the GAI 5 crops. The application of foliar urea did not always result in an increase in grain yield or quality and the partitioning of biomass and N to the grain was also seemingly unaffected by the application of foliar urea. However, yields from GAI 5 crops receiving late-N as foliar urea, irrespective of the method of application, were not significantly different to those obtained from Ncf crops. The amount of N deposited and the pattern of deposition were affected by canopy size. Applications made prior to ear emergence penetrated more deeply into the canopy. The top half of the canopy, flag leaf to flag-1 and the ear when present, was the most important site for both N interception and uptake. A maximum of 60 % of the applied N was intercepted by the GAI 5 crops and 10 % remained on the surface of the crop 96 hours later. 35 % of the N 'lost' from the crop surface was taken up over 96 hours. Of the remaining 40 % of the applied N, an estimated 10 % was lost by volatilization, 5 % by drift and 25 % penetrated to the soil surface. N uptake from the leaf surface probably followed an exponential pattern through time. The time for half of the N present initially to be lost (t0.5), was unaffected by the side of the leaf to which N was applied, the age of the leaf growth stage of the plant or the amount of N applied. t0.5 was improved only by the addition of a spreader or a penetrant. By harvest up to 64 % of the fertilizer N applied was recovered by the GAI 5 crop of which 87 % was present in the grain. Studies using N15 labelled urea suggested that N was transported away from the flag leaf immediately after application, but it was not clear whether N was transported directly to the ear or used in leaf metabolism elsewhere.

This thesis attempts to provide a general history of the tithe system during the last century and a half of its existence in its old form. It attempts this partly through a detailed study of one county, thus enabling a wider variety of legal, administrative, ecclesiastical and parochial documents to be used than has been attempted in previous studies of the tithe system. Staffordshire was selected partly because of its excellent source materials in the Stafford County Record Office, the William Salt Library and the Lichfield Joint Record Office, and partly because the county provides a most useful admixture of different agricultural and industrial settlements. As Caird wrote in 1850: 'The state of agriculture in Staffordshire is influenced by such a variety of circumstances that examples of every system pursued in England may be found in this county.'(1) It was therefore possible to assess whether the tithe system had a differential impact on different types of farming, and how much it penetrated industrial areas. The thesis attempts to show how tithe was collected in the eighteenth and early nineteenth centuries, and how far tithing in kind remained. The importance of lay as well as clerical tithe owners is studied and the thesis attempts to indicate the amount of social tension occasioned by the system. As litigation over tithe was frequent in much of the period, the complexities of the legal situation are studied and an analysis made of the Staffordshire cases, indicating the major reasons for litigation, what evidence was considered valuable, how cases were settled, and the importance of legal costs in the progress and determination of disputes. One particularly lengthy tithe battle - from Cheadle - is treated as a separate case study. A case study of the Quaker attitude to tithe, as the leading dissenting sect objecting ID its payment, is also made, indicating the degree of non-payment by Quakers, their legal tussles, persecution and campaigns to change tithe law. The national campaign against tithe is studied with consideration and evaluation of the arguments of both sides in the light of the actual situation. The reasons for the increasing momentum and bitterness of the campaign from the late eighteenth century onwards are assessed. As the eighteenth century enclosure movement provided the first major opportunity since the Reformation for a change and redistribution of tithe property, attention is paid to the impact of the movement, indicating how far tithe was exchanged for land at enclosure. The relative benefits to land and tithe owner are assessed. The thesis concentrates finally on the parliamentary attempts to reform the system, and the difficulties encountered there. The origins of the 1836 Commutation Act are studied together with an analysis of the Act and its intentions. The last chapter is devoted to a study of the Act in operation, showing how easily commutation was effected, how tithe values were altered, and how the parties concerned reacted to the changes which commutation would bring. The thesis ends at 1850 with most commutations, and their attendant redistribution, complete. Above all, however, this study attempts to explain how men attempted to make an anachronistic system work in an increasingly complex society, how far compromises were necessary and acceptable, and how far tithe was responsible for tension in the village community. It attempts to provide a general history of tithe, but it does so in the belief that, because tithe was a local and parochial burden, its proper impact and effects cannot be properly understood without detailed reference to local situations.

Two selective media which specifically allow the cultivation of Bacillus thuringiensis while it is in the vegetative as opposed to the spore form were developed. Using these media it was conclusively proved for the first time that B. thuringiensis can reside on the phylloplane in a metabolically active form. This was corroborated by evidence, also for the first time, that conjugation can take place on the phylloplane between such endemic strains. A new bacteriophage, infecting one of the endemic stains, which was activated by the process of genetic recombination, was isolated and characterized. The appearance of naturally occurring strains of B. thuringiensis in vegetative and spore form was followed over a growing season on clover (Trifolium hybridum) in the field. Simultaneous and sudden rises and declines of both spore and vegetative cell densities were observed. These could not be correlated with weather conditions. A genetically stable population of strains seemed to be maintained throughout the growing season. The most common other spore-former on these leaves was Bacillus cereus but the fluctuations in appearance of these two very closely related species were not co-incident. Using specific PCR primers, a considerably diversity of toxin types was found with the majority of isolates possessing multiple d-endotoxin genes. Bioassays against a lepidopteran insect (Pieris brassicae) of purified d-endotoxins showed that they were not more potent than those from a laboratory-adapted strain. A high percentage, however, of the endemic isolates (82%) possessed the ‘Vegetative insecticidal protein’ (Vip) gene, vip3. This might indicate an involvement of Vips in the establishment of these strains on the phylloplane. A mechanism for colonization of annual plants by B. thuringiensis was demonstrated for the first time. It was shown that spores added to seeds, even in non-sterile soil, can germinate and replicate on the resulting seedlings. The level of colonization achieved did not have a consistent influence on the feeding behaviour of third instar larvae of P. brassicae which were present on the plants for three days. Nevertheless, the fact that the number of CFU of B. thuringiensis recovered per gram of insect increased with time is evidence of proliferation of the bacterium inside the insects. Four isolates of B. thuringiensis that had been recovered in the vegetative phase from the phylloplane of T. hybridum were grown for 500 generations in a rich medium. Changes were observed in all of the strains but one isolate changed remarkably in all of the characteristics assessed which included: structure; plasmid profile; fatty acid composition; and d-endotoxin production. Moreover, the sequence of the Vip3 protein harboured by the evolved strain showed changes when compared with that of the parental strain.

The present study evaluated the effect of three host plants: chickpea, Cicer arietinum, tomato, Lycopersicon esculentum and cotton, Gossypium hirsutum, on the efficacy of Helicoverpa armigera nucleopolyhedrovirus (HearNPV). The results showed that HearNPV was inactivated within one hour when sprayed on to the leaf surface of chickpea indicating that leaf surface factors on this plant were responsible for the effect. In contrast, virus that has been sprayed onto the leaf surface of cotton and tomato was not significantly affected compared to untreated HearNPV. This study also showed that HearNPV was inactivated on the chickpea leaf surface in field experiments. One compound was shown to be induced on the chickpea leaf surface in response to spraying with 0.02% Triton X-100 which was used as a surfactant. The induced compound was isolated and identified as sissotrin, and isoflavonoid. Sissotrin was shown to reduce the efficacy of HearNPV, although not by as much as when the virus was exposed to the chickpea leaf surface. The results indicated that sissotrin was partially responsible for the inactivation of HearNPV and that other compounds which accumulated on the leaf surface after spraying with HearNPV must also have an additional effect in combination with sissotrin. This is the first study to show that isoflavonoids reduce the efficacy of baculovirus against Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Field trials were also conducted with different low cost additives mixed with HearNPV on chickpea crop and these increased the efficacy and persistence of HearNPV under field conditions. This study may therefore help to improve biopesticide based pest management on chickpea.

The thesis examined the effects of climatic change on livestock production within Scotland. In order to achieve this, a systems model of the dairy, beef and sheep enterprises was developed. Climatic change primarily affects livestock production through its effects on forage production. Under climatic change, the model predicted that the length of the growing and grazing season will increase with the extensions occurring at both ends of the season. Relative to current climatic conditions elevated CO2 concentrations coupled with the associated changes in climate resulted in an enhancement in harvestable dry-matter yield that ranged from 20% to nearly 60% and increases in the percentage of white clover in the harvestable material by up to 126% In general, global warming is predicted to increase forage and livestock production within Scotland. However, the location of the site is also important in determining the effect of climate change as the magnitude and, in some cases, the directions of the changes varied between sites. The effects of climate change were also dependent on the actual level of changes in temperature. In addition, there were interactions between CO2 concentration and both temperature and rainfall, as well as interactions between temperature and rainfall. Although the three enterprises showed similar trends in their response to climate change, there were differences in the magnitude of the response as well as differences in the factors that resulted in significant changes. There were also differences in the response of the grazed and the ungrazed swards. This underlines the complexity of the interactions and the difficulty of extrapolating the results to other locations and to other levels of climatic conditions. The advantage of developing a model is that all these complex interactions can be captured and potentially the site - specific consequences of climate change on forage and livestock production predicted.

This study relates to the reforms by the Education Ministry in Botswana of decentralising the coordination of teachers’ In-service Professional Development (IPD) to the Regional Offices with the overall aim of improving students’ academic performance (Republic of Botswana, 2006). In the absence of other research data, the study aims to understand how secondary school teachers of agriculture in Botswana perceive their IPD. The study endeavours to identify gaps in current IPD provision and make recommendations to guide IPD policy reforms at regional level. Based on a review of the literature and the overarching research purpose, a set of research questions was devised. Considering the research questions, a Realist perspective to the research that endorses a flexible pragmatic stance was adopted. The research employed a mixed methods design. A questionnaire was developed and administered to all the Agriculture teachers in the Central Region (n=247). A purposive sample of teachers (n=36) and every Agriculture Education Officer (n=8) were interviewed. The quantitative data was analysed using SPSS software, with descriptive and inferential statistics reported. A coding guide was developed to analyse the interview transcripts which was done with the assistance of NVivo software (Bazeley, 2007). The findings show that the main source of motivation for teachers to attend IPD is to update their knowledge and skills in the subject. The study revealed workshops and meetings to be the most popular IPD opportunities of all IPD opportunities found to be relevant by teachers. The study also identified satisfactory and unsatisfactory characteristics of IPD; the contextual factors that adversely influence IPD in the region; and a wide range of IPD needs. The findings have implications for future IPD policy reforms; most important of these include the need to:  adequately resource IPD and create time for it as an integral part of the education programme;  remove restrictions associated with funding teachers’ enrolment in part time courses;  revise teachers’ workload policy to help them find time for IPD; and  have IPD emphasise acquisition of agriculture skills by teachers. Beyond policy, the findings also suggest improvement of the design and organisation of IPD, which include strategies for making IPD interesting, meaningful, sustainable and accessible to all teachers in the region.

Food sovereignty is an alternative agricultural and rural development paradigm advocated by the international peasant movement La Vía Campesina. This investigation analyses food sovereignty through a historical cross-scale analysis focusing on the livelihoods of peasants in the sertão in North-Eastern Brazil. The overall aim is to assess the implementation and local effects of a policy, which is based on three food sovereignty principles, and determine in what ways and to what extent it promotes food sovereignty in practice. The three food sovereignty principles considered were support of peasants and small-scale family farmers, prioritisation and support of local food systems and commerce and promotion of agroecology. The policy analysed is the Brazilian government’s Food Acquisition Programme (FAP), as implemented in Mirandiba, Pernambuco by the NGO Conviver from 2005-2008. The analysis involved an assessment of the production and earnings by 359 participating families from 18 poor rural communities, as well as detailed case studies of the livelihood strategies of 14 families from two communities. A number of policy debates are explored, including rural poverty, food security and sustainable agricultural and rural development, to which this research provides three main contributions. Firstly, a new framework to explain the process of marginalisation of peasants through the influence of five mediating factors. Secondly, this framework helps deconstruct misconceptions about peasants and thereby provides support to La Via Campesina’s defence of ‘peasants’ and their livelihoods. Finally, as the first known indepth study of the implementation of the FAP on a local level, this investigation contributes to fill a gap in the research and literature on the operation and local impacts of both the FAP and governmental food procurement programmes more generally. This thesis argues food sovereignty can be achieved locally even within a context of general globalisation, through policies such as governmental food procurement programmes. The investigation concludes that food sovereignty is being pursued in areas of Brazil through the FAP and other progressive policies and movements, which are enabling peasants to improve their well-being, food security, self-esteem and to forge an adequate livelihood. The FAP is also contributing to the development of local food commerce systems and the promotion of agroecology both in Mirandiba and Brazil

Future food security is under threat from both climate change and human population growth. Water scarcity is a major limitation to crop production worldwide and the effects of climate change are likely to exacerbate this. Furthermore, an ever increasing human population is driving our demand for food, fuel and fibre. In combination, climate change and population growth, and their interaction, creates a complex problem with regards to improving plant productivity with which to maintain food security. If crop production can be made more efficient, agricultural intensification can be achieved without the need to expand the world’s cropped area, which is unfeasible. Leafy salad crops are of significant nutritional value and are eaten globally, thus making them an exciting target for improving resource use efficiency in agriculture. This research focuses on water as a resource and takes two complementary approaches. Firstly, to improve the crop genetically so it produces more ‘crop per drop’ without a detrimental impact on yield. Secondly, the aim was to improve irrigation management in a commercial setting in order to use water more efficiently while attaining optimal crop yield and quality. Candidate SNPs within the lettuce genome have been elucidated which control both fresh weight and water use efficiency and these can now be used to inform a marker assisted selection breeding program. This breeding will produce a more water use efficient lettuce crop, which is not compromised in its ability to produce biomass, while also retaining the favoured traits of currently used commercial crops. Furthermore, it has been demonstrated using thermal imagery that water savings of almost 20% can be made in a commercial setting without any impact on crop yield or quality. The water savings which we have provided, if extended commercially, will confer significant savings in terms of water, waste and money.

Lignin is a complex phenolic hetropolymer with an established role in structure, support and defence in higher plants. The chemical structure of lignin is as yet undefined but controlled by an enzymatic pathway leading to three monomeric subunits. Lignin accumulates in plants in response to pathogen challenge. A scanning densitrometric assay to detect lignin was developed that was non-invasive, quantitative and quick to perform. The assay was used in conjunction with assessments of phytotoxicity, mycotoxity and pathogen resistance to assess the efficacy of potential biochemical inhibitors of the phenylpropanoid pathway in vivo. With this information, tolerances for biochemical inhibition of the phenylpropanoid pathway were obtained. This allowed further investigation of the basis of genetic and metabolic regulation of one form of one enzyme of the pathway, phenylalanine ammonia lyase, in wheat. Evidence of a potential role for endogenous elicitation in the ligninification pathway was also gained by the use of the assay. Elicitation in terms of the hypersensitive response was also investigated during attempts to purify the fungal elicitor Avr2 using the tovnaXo!Cladosporium fulvum model; however this work was completed by an alternative genetic screen protocol published elsewhere. Control of ligninificiation and the enzymes that produce the polymer is therefore an essential part of the defence response in wheat. This has important implications for genetic modification of the pathway. It was shown in this study that the phenylpropanoid pathway controls one aspect of resistance in wheat and concludes that care must be taken when manipulating the pathway in plants for increased digestibility or ease of pulping. In addition, a separate project was undertaken in order to purify an avirulence protein possessed by the Cladosporiumfulvum fungus. The projects aim was to obtain amino acid sequence(s) of potential interacting proteins that would be used to design primer sequences to provide a genetic sequence of the target avirulence protein Avr2. Although several candidate proteins were obtained and amino acid sequencing attempted; a competing group obtained the genetic sequence of Avr2. The sequence of this clone predicts a protein whose molecular weight and isoelectric point falls within a region of proteins whose isoelectric points and molecular weights show activity in a bioassay for Cf-2 interacting proteins. This data supports the conclusion that the work by Luderer et al (2002) defines the genetic sequence of Avr 2.

This thesis explores the spatial patterns in the vulnerability of the rice-wheat production systems of Punjab and Haryana to climate. Remote sensing monitoring is used to identify rice and wheat crop extents and to capture dynamics of the cropping system such as length of growing periods and cropland productivity. This remote sensing monitoring is integrated with analysis of climate datasets and other measures of the agricultural system to 1) identify the exposure of rice-wheat croplands to harmful climate drivers, 2) capture the sensitivity of the rice-wheat croplands to climate and to 3) inform targeted adaptations to improve climate resilience, ensure environmental sustainability and sufficient levels of production, the pillars of a climate-smart landscape. Across all India, including Punjab and Haryana, there was a fragmented spatial pattern in the occurrence, and sign, in trends of monsoon precipitation. This highlights the need for locally sensitive water resources management. Over 5 million ha of rice-wheat croplands in Punjab and Haryana were exposed to unfavourable trends in facets of monsoon precipitation; this was mainly exposure to increasing recurrence of drought years and increasing inter-annual variability in monsoon precipitation. However, crop yield-climate regression models indicated that precipitation is not influencing variability in rice or wheat crop production but growing season temperatures are. Average minimum and maximum temperature during the thermo-sensitive periods of crop development have a greater negative impact on wheat crop yield than exceedance of critical temperatures. The negative impact of warming on wheat crop production increased with later start-of-season dates. Through an integrated use of remote sensing datasets the spatial patterns in the magnitude and varying nature of the vulnerability of crop production to climate were captured. This enabled identification of location-specific stresses, such as later sowing dates, and targeting locally optimum adaptations.