School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemNitrogen fixation by Casuarina oligodon agroforestry in the Papua New Guinea central highlands( 2006)Casuarina oligodon L. Johnson is a multipurpose tree species grown in the highlands of Papua New Guinea (PNG). The integration of C. oligodon into agricultural systems is seen by villagers as means of restoring soil fertility, controlling soil erosion, providing shade for crops and producing fuel wood and building materials. Biological nitrogen fixation by C. oligodon through symbiotic relationships with Frankia (micro-organism) under field conditions in short (5-10 years) and long (11-15 years+) fallows in the PNG central highlands was investigated using the 15N natural abundance technique. Results from the study showed that as much as 70% of N in C. oligodon was derived from the atmosphere. The rate of N2 fixation was relatively low in short fallows of casuarina and increased as the trees aged in the long fallows. A rate of N2 fixation up to a maximum of 36 kg N ha -1 year -1 was estimated based on commonly practiced tree stocking rates and field conditions in the PNG highland areas. Although casuarina fallows tend to accumulate higher total N and C compared with equivalent period of grass fallows, the amounts of N and C in the surface soils of all systems under the study showed no significant difference. The amounts of total N and C under long fallows of casuarina (11-15 years+) were generally greater than short fallows of casuarina (5- 10 years). A significant proportion of the total N was stored in the above ground biomass of trees that were more than 10 years of age. Management of the standing biomass, particularly when the fallow is converted back to the cropping phase, is therefore critical in ensuring that the farmers are able to gain maximum benefit from the fixed N. Whilst the removal of stem wood for use as fuel or building material may be an important product of the agroforestry system, retaining the foliage, small branches and bark on the site is vital in sustaining agricultural productivity.
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ItemCardamom cultivation, livelihoods and biodiversity in a H'mong farming system in Northwest Vietnam( 2005)The recovery of the cardamom market in northwest Vietnam since the mid-1980s has seen many new groups of small farmers engage in the cultivation of this crop. A particular type of cardamom (Amomum tsao-ko) has a long history of cultivation by H'mong people in the Hoang Lien Mountains of northwest Vietnam. This thesis examined the implications of cardamom cultivation for H'mong livelihoods and forest biodiversity in those mountain farming systems, and explored options for improving farmer livelihoods through cultivation of this crop. Cardamom is in demand for both its aromatic and medicinal properties. It is providing a key source of income for H'mong ethnic farmers living at higher altitudes, people typically isolated from many other markets. The perennial crop requires partial shade and cool temperatures and for these reasons farmers utilize montane forest for its cultivation. These forests are also important for their biological diversity. Some cardamom cultivation practices (including tree felling to allow light to the crop) have been identified as having potentially negative effects on biodiversity. In this study a (partial) Farming Systems Research approach was adopted, which involved describing the farming systems at three (case study) villages, and identifying implications of cardamom cultivation for livelihoods and biodiversity at each site. Farmers were making transition from upland crops (rice and maize) to wet rice cultivation through the use of terraces to meet subsistence requirements, and had adopted cardamom as a cash crop despite the major labour inputs required in establishment. Extensive areas of forest and/or grassland on steep slopes dominated village sites. Cardamom was found to provide a key source of cash income for almost all farmers in the study area and had raised household income levels above the government-defined poverty level. Growers were committing significant labour resources over the initial five years of cardamom establishment, prior to receiving income. This labour on cardamom production competed with, but did not entirely replace, labour input towards improving subsistence income, i.e. establishing terraced fields for rice. Market uncertainty for cardamom presented some risk to small-scale farmers' livelihoods. If the cardamom market were to become flooded or depressed, the outcome would be a major setback for a large proportion of households, given the modest income from other cash crops and low total current incomes. Future inquiry aimed at better market understanding and ensuring stable income levels is recommended. Cardamom fields contained a higher number of plant species representative of montane forest, and in general much more favourable habitat for forest dwelling fauna than existed in alternative agricultural land-use types such as rice fields, upland fields or grassland. Tree cover was reduced by 25-50 per cent as a result of cardamom field establishment in forest, but there was no selective tree species removal. The lack of knowledge of the effect of forest thinning for cardamom cultivation on fauna habitat and animal movement means the abundance of some fauna species may be decling without our knowledge. However, farmers' involvement in cardamom growing ensured that forest would not be removed for other (less biologically diverse) types of land use. Farmers from certain villages have asserted de facto local use rights over particular areas of montane forest through their establishment of cardamom fields. As a result, some farmers had gained access to montane forest for cardamom cultivation - where they had no access to land previously. Research on cardamom production should focus on providing opportunities for farmers without access to montane forest, to grow cardamom in agroforestry systems on suitable land types near their villages. Farmers could be involved in `adaptation' trials aimed at developing new agroforestry systems using shade from planted tree species - as has been achieved in India and other regions. Such agroforestry systems on existing agricultural land may also make a positive contribution to forest biodiversity by increasing total vegetation.
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ItemSpontaneous agroforestry : regreening barren hills in Vietnam( 2003)This research concerns deforestation and the persistence of shifting cultivation in the uplands of Vietnam. Continuous cultivation of annual crops has resulted in large areas of hillside land becoming degraded grassland. Policies designed to support reforestation have been effective in stimulating spontaneous agroforestry development by farming households in certain parts of the country while in other areas deforestation continues. This research set out to explain the necessary conditions under which farmers in upland areas may spontaneously develop agroforestry systems in place of annual cultivation of agricultural crops and hence contribute to restoration of forest cover. The newly postulated 'keys to small-holder forestry' model formed the basis for the research. The case study method was selected because it was the most appropriate for testing the keys to smallholder forestry model and because insufficient resources were available for undertaking a questionnaire survey based method. The model was tested in a case study village in which farmers were spontaneously substituting shifting cultivation on hillsides with a form of agroforestry based on cultivation of bamboo. Data on the reasons why farmers chose to change their use of hillside land were collected using individual household semi-structured interviews, direct observation and focus group interviews. A visioning process was also used to assist in understanding the aspirations of the farmers. Methods used to analyse policy and the impact of particular programs on farmer decision-making included the use of secondary sources and interviews with government officials. This study is thought to be one of the first village level studies in Vietnam that seeks to explain farmer decision-making on agroforestry within the context of the entire household production system and incorporating the influences of policy, macroeconomic forces and village history. Understanding farmer decision-making is considered to be an important prerequisite to the development of strategies and programs that will support the development of environmentally sustainable and economically viable production systems on sloping land. Understanding farmer decision-making within a dynamic context necessitated the use of a systems approach, focused on livelihood security at the household level. The major conclusion to emerge was that the 'keys to small-holder forestry' model successfully predicted the conditions under which farmers adopted agroforestry in the case study village. As predicted, farmers expanded their agroforestry plots when this provided greater economic benefit to the household than alternative enterprises. In the case study, agroforestry was an attractive alternative to agriculture because of the high returns to labour, low capital investment and the high social security value. Agroforestry species were also better adapted to the degraded soil conditions than agricultural crops. Supporting factors, also predicted by the model, included favourable markets, a favourable institutional and policy environment, especially secure land tenure, knowledge of a suitable production technology and acceptable control over risk. Market forces were found to be a particularly strong incentive for spontaneous agroforestry development by smallholder farmers. This points to the possibility of using market based policy instruments that have been little utilised in the past for promoting agroforestry. The 'keys to smallholder forestry' model potentially provides significant new directions for policy making and for the design of agroforestry extension programs in Vietnam and South East Asia. In particular it provides a framework for integrating two of the major imperatives in upland development. The first is the need for environmentally sustainable production systems that are within the management capacity of farmers and the second is the need for economic benefit for individual smallholder households in order to alleviate poverty. The research demonstrates that, under the appropriate conditions, farmers' goals for sustainable production and government objectives to regreen barren hills may be compatible.
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ItemIssues for enhancing farmer participation in farm forestry research in Australia( 2002)For many years, the scientific and professional community have determined the priorities for agriculture research with little input from farmers. Farm forestry may be a new industry but it already faces the dilemma that other agricultural enterprises have experienced, where farmer research needs are not being met, adoption of new technologies is slow, and as a result further development is inhibited. For other agricultural industries these issues have lead to the adoption of collaborative or participatory approaches of securing farmer input into the priorities for research, from defining the research needs to carrying out the work and disseminating the information. Through a series of focus group discussions, farm foresters who have been involved in the Australian Master TreeGrowers Program and members of the farm forestry research community were asked to provide their attitudes and opinions towards farmer participation in farm forestry research. The objective was that these comments and perceptions might provide insight into the potential and constraints facing farmer participation and highlight opportunities for establishing a more participatory approach to farm forestry research. A qualitative methodology and analysis of results highlighted many issues that impact on farmer and scientists attitudes towards participatory research. It also highlighted that farmers and scientists see a role for farmer participation in defining research needs, but that involvement in other stages of the research would depend on a number of factors. In terms of encouraging a participatory approach to farm forestry research, the scientists believe in the use of `leader' farmers, whereas the farmers supported the use of grower groups and coordinators to facilitate the process. The outcomes also highlighted the need to develop methods for getting farm forestry information to farmers, that research organisations need to become unified in their approach to farm forestry research, and that the scientific community needs a culture change to accept participatory research as a legitimate means of investigation.