No description available.

Appraisals of investment in pest control are complicated by the problems of predicting events in biological systems. In this study, an attempt is made to estimate the two necessary components of pest control investment appraisal, namely: the production function (decreases in crop losses with unit increases in pest control investment), and the pest damage function (relating crop damage to changing infestation variables), for attacks of the lepidopterous larvae of Spodoptera I1ttoralis (Boisd.), on Cypriot lucerne pastures. It is suggested that at present the best technique available to farmers for controlling S. littoralis infestations is the single application of one of three insecticides of proven efficacy. Consequently, the cost of successful pest control is represented by one value for a wide range of larval densities. The pest damage function is described as a dynamic relationship between a number of changing environmental and crop variab1es and is presented in the form of a computer simulation. This incorporates some of the existing empirical data on pest consumption and pest and crop interaction as well as much of the additional data collected by the author. The damage and production functions are compared, and estimates are made of the minimum larval density at various timings in the crop growth cycle, which is sufficient to cause losses equal to the treatment costs (the economic threshold of treatment). These estimates are offered as a basis for decision making on the economic control of S. littoralis in Cypriot lucerne fields.

Nitrification is central to the global cycling of nitrogen and is important for primary production and other processes in marine systems, where nitrogen is generally the limiting nutrient. The majority of studies on nitrification, however, have focused on terrestrial systems, where this process can cause significant losses of N-based fertilisers from agricultural land. Comparatively little is known of nitrification in marine systems and the organisms involved. In addition, technical difficulties in isolation of pure cultures of ammonia-oxidising bacteria have severely restricted studies of species diversity and community structure of these organisms. In this study, molecular technology, based on the 16S ribosomal RNA (rRNA) molecule was applied to the characterisation of marine communities of ammonia-oxidising bacteria. PCR primers were designed for specific amplification of the rRNA gene (rDNA) from ammonia-oxidisers belonging to the beta-subdivision of the Proteobacteria. These primers were used to characterise both enrichment cultures and communities within polluted and unpolluted sediment samples. These studies indicated considerable diversity of beta-subgroup ammonia-oxidisers within marine systems which has not previously been detected. It was also shown that enrichment and isolation techniques select for strains belonging to the genus Nitrosomonas while the majority of sequences obtained by direct analysis of rDNA amplified from total genomic extracts belonged to the genus Nitrosospira. In addition, novel isolation methods were developed which considerably reduced the level of heterotrophic contamination and greatly facilitated isolation of pure cultures. In situ probing, using fluorescently labelled rRNA oligonucleotide probes, indicated that CCD microscopy is less sensitive than UV microscopy alone due to quenching of the signal.

Abstract The purpose of this study was to investigate how grocery stores perceive the increasing demand for organic food among Swedish consumers. Furthermore, I have studied how Swedish consumers perceive the supply of organic foods in grocery stores. This comparative study aimed to shed light on the problems and opportunities this development brings, and how the control of organic food is conducted. The primary source for the results consisted of information gathered from two surveys: a consumer survey and a store survey. The majority of grocery stores in this study answered that there has been an increase in sales of organic food and this trend is noticeable. More consumers are demanding organic food in the stores and shortages in the organic supply is becoming increasingly prevalent. This development encouraged consumer’s environmental awareness in the grocery store and promotes increased interest in how the goods are produced and transported. Large areas of agricultural land should be converted to organic agriculture to meet this increasing demand for organic food. Some studies have proven large scale- shift to organic farming without food shortages. Sweden has both preconditions for sustainable agriculture produced with local renewable resources and has the most stringent regulations and higher standards in food production than other countries. Therefore, local production needs to be prioritized. A sustainable agriculture is a necessity in the future; that can both reduce its carbon footprint and at the same time respond to the world's increasing food supply.

No description available.

Bamboo growing is strongly associated with farm size (landholding), wealth, household size, food sufficiency, irrigation facility, livestock owned, land tenure, household off-farm and on-farm incomes, physiography of the land, and access to forests. The landholding is the most important socioeconomic factor that influences households decision to grow bamboos. Bamboo growing also varies with ethnicity as socially and economically disadvantaged ethnic groups are less likely to grow bamboos on farmland than other ethnic groups. The literacy and age of the household heads are not strongly associated with bamboo growing on the farmland. Bamboo is the most commonly planted species in villages in the Midhills. They are the preferred species for planting, both on private land and in community forests. As timber is getting scarce, bamboo is increasingly used as a replacement for timber. They are also the best fodder species (particularly Bambusa nutans) in the Terai and the fifth best in the Midhills. The interest in bamboo planting is particularly high where there is better access to the markets and bamboos have already been identified as one of the important species for use in income generation programmes. There are many taboos, superstitions and beliefs, particularly in eastern Terai, against bamboo planting which prohibit households from further bamboo planting. Had there not been such beliefs, there could have been more bamboos on the farmlands of eastern Terai and Midhills than at present. Bamboo is also one of the most remarkable woody perennials in eastern Nepal. There are many households, both in the Terai and the Midhills, who are dependent on the income from bamboo craftmaking. Most of the traders are newcomers with lack of resources to expand the trade. Many bamboo growers who sold bamboos, craft makers and traders were not happy with their income and suggested various steps for improvement. There is also a need to review many of the HMGN policies as many of them contradict each other and are therefore unfavourable towards stimulating the growing of bamboos in Nepal. It is clear that a detailed development plan to improve the use of bamboo resources is needed. Socioeconomic research on bamboos should be extended to other regions of Nepal in order to inform the new development plan.

The aim of this research is to examine the contextual environment in which farmers operate so as to improve our understanding of the factors shaping vulnerability to climate risk. A key focus is on the livelihoods of sugarcane farmers, using a case study of small-, medium-scale (emerging) and large-scale sugarcane farmers in the KwaZulu-Natal Midlands area of Eston and its surrounds. A social vulnerability assessment was undertaken under the Sustainable Livelihoods Framework (SLF) to test the hypothesis that climate risk is considered a major contributing factor to the vulnerability of commercial farmers in KwaZulu-Natal and needs to be effectively managed. This involved an investigation into the multiple stresses (both external and internal, on-farm and off-farm, climatic and non climatic) acting on the system. It is clear that climate change risk and variability is a major, but not the sole contributing factor to the vulnerability of commercial farmers in this part of KwaZulu-Natal. Climate change does need to be effectively managed but it will be best done in conjunction with the management of the other multiple and interacting threats and stresses identified in this study. Climate change and vulnerability, as well as the other multiple stresses, are acting on an already vulnerable system, exacerbating and compounding present risks. This research also explored a number of coping and response strategies that commercial farmers have adopted in response to the threats and stresses and investigated particularly, what elements enhance or restrict these strategies (both on-farm and off-farm). These strategies posses potential as possible future adaptation options. It was found that the issues of access to livelihood assets (social, financial, natural/environmental, physical, human, knowledge assets and capital under the SLF) are key to the adaptive capacity and the adaptation strategies that farmers employ. Institutions (both formal and informal) play a pivotal role in this access to livelihood assets both enabling and restricting access. In conclusion, this work determined that a focus on only one element, such as climate change, will not significantly reduce the vulnerability of commercial farmers. There is an interactive, dynamic and multifaceted network present with a number of factors acting within and from outside the system. Political, biophysical, social and economic factors interact and combine to compound vulnerability, requiring more integrative and multiple response strategies.

No description available.

The thesis examines the role of the state in the agriculture sector with particular emphasis on policy formation and it's effects on rural Wales. Sociological theories of the state are examined and an 'institutional' approach is adopted which focusses attention on the institutional actors in the policy process. Policy is made by these actors albeit under certain external constraints. A brief analysis of state intervention in the UK is provided. This is treated historically and traces the-changing pattern of state involvement in the industry. Likewise, the UK policy process is briefly examined and the main institutional actors are identified. At the Welsh level, the effects of state intervention on the structure of Welsh agriculture are documented. This is also treated historically. Attention is then directed to the Welsh institutional actors and their role in the agricultural policy process. In particular, the role of the Farmers' Unions is examined, looking closely at their relationships with state agencies. The activities of non-agricultural state agencies operating in rural Wales are also examined. The question is asked whether the traditional dominance of agricultural policy in the Welsh rural areas is about to come to an end. While some evidence is put forward to support this, the situation is by no means clear and no definitive answer can be provided. In conclusion, it is argued that the effects of past agricultural policies on the communities of rural Wales have been extremely damaging, and some reorientation of policy is clearly needed. However, the institutional. analysis indicates that such a reorientation will be extremely difficult to achieve.

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