School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemNo Preview AvailableVillager participation in native forest development : the impact of social forestry in Fiji(University of Melbourne, 1993)As owners of extensive forest resources, the Fijian people have an opportunity to utilise these resources for village development. Villagers are very conscious of their low living standards compared with urban areas. It is widely accepted that expanding local employment and business opportunities is necessary to improve rural living standards, and rural Fijians hope that the forest industry will help them to achieve this. The object of this research project is to evaluate the success of social forestry as a methodology for achieving village development in Fiji, particularly the contribution of Fijian villager participation in the native forest industry. Forestry activities earn cash benefits for rural villagers in the forms of land rentals and timber royalties. Social forestry programmes involving villager participation in planting projects were seen as way to enhance rural development. To further increase the benefits obtained from forestry many Fijians have become actively involved in forest harvesting and timber processing. Though there is a high potential for achieving significant benefits by Fijian participation in the forestry industry, the actual benefits received are determined by the type of activity, the level of participation and the performance of the participants. The study involved surveying in seven villages on the islands of Viti Levu and Vanua Levu, as well as short interviews with many Fijians involved in the forest industry. The villages covered a range of villager forestry participation types, including casual and contract employment in logging or planting, village community fund-raising contracts, a proposed joint venture logging project and a small logging company. 'Development' appears to be fairly consistently interpreted across rural Fiji as the improvement of village services and homes; hence in the eyes of the villagers, forestry does contribute to development. The surveys show that forestry can make a significant contribution to the village economy in the form of cash and employment, but the contribution of forestry towards village development is dependent upon the use of the income generated from forestry. These uses vary between the villages, but commonly include the purchase of consumables, such as food and tobacco, paying school fees, home improvements, roads, churches, schools, and other communal amenities. There is a significant difference in the contribution of forestry to employment and income between the two islands; forestry is more important in rural development on Vanua Levu. Social structure in the village, village leadership, assistance from government or financial advisers, and the level of integration of the village into the market economy, all appear to affect the investment and management of forestry funds. These aspects exert the most influence on the amount of 'development' that can be achieved through forestry programmes involving Fijian landowners. Logging businesses achieved higher cash returns than other types of Fijian forestry participation, but were plagued by difficulties. Businesses in logging, sawmilling and manufacturing of higher value-added products such as veneer and furniture are the most profitable area of the forest industries in Fiji. The potential for Fijian villagers to become involved in these enterprises is severely limited by access to credit as well as their paucity of management and administrative skills. But where the potential for forestry participation exists and motivation is provided by a community leader or individual, social forestry activities can effectively promote rural development and viable village communities in Fiji.
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ItemAn economic analysis of Nigeria's import substitution policy for rice and wheat( 1993)The study involves analyses of substitution effects of Nigeria's import restriction imposed on rice and wheat; in terms of domestic production, consumption and prices. The theoretical and empirical literature on uncertainty, risk and self sufficiency under international trade is reviewed, as well as smuggling and its welfare implications. The analyses involves use of regression and correlation models. The result shows that increase in price of wheat would reduce per capita wheat consumption, thereby shifting consumption to maize and millet. It is found that wheat and rice are inferior commodities in Nigeria. In addition, increase in the prices of yam and maize would increase per capita rice consumption . Therefore, yam, maize and rice are substitutes in consumption, so also are wheat and rice in production. An increase in price of rice would increase rice area while increases in prices of maize and wheat would increase wheat area. While increase in the price of rice would lower wheat production, thereby favouring rice production in the longrun. Accordingly, increase in world prices for rice and wheat would lower their domestic prices. While increase in tariff would increase domestic wheat producer price. Between 1973 and 1986 prices of most food commodities in Nigeria increased both nominally and in real terms. In addition, real prices for rice and wheat slumped between 1987 and 1989. Retail prices were always higher than producer prices. It is concluded that insulating domestic prices and supplies of rice and wheat is no panacea to problems associated with price instability, self sufficiency and balance of payments. Sustainable policies, such as consumption tax; use of futures markets; diversification and appropriate exchange rate are the best policy options.
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ItemAn analysis of radiata pine-pasture agroforestry systems( 1993)Agroforestry, the integration of forestry and agricultural production, requires an understanding of the interactions between trees, agriculture and the environment. This thesis presents an analysis of the effects of a variety of Radiata Pine-pasture agroforestry treatments on soil water, tree growth and form and pasture production together with a series of economic analyses using the FARMTREE model to simulate the various agroforestry regimes established at Carngham in western Victoria. The Carngham study site consists of a replicated randomized block design of five Radiata Pinepasture treatments. The treatments were: open pasture (no trees), 100 trees/ha (8 m x 12 m), 277 trees/ha-wide-spaced (4 m x 9 m), 277 trees/ha-5 row (5 rows, 4 x 3 m, with 10 row gap) and 1650 trees/ha (no pasture). Results, 11 years after tree establishment, show that soil water content under the various treatments has a cyclical pattern of recharge and discharge with an annual amplitude of approximately 100 mm. Within the 100 trees/ha and 277 trees/ha-5 row and 277 trees/ha-wide-spaced treatments, the soil water content was generally significantly less than under open pasture in the upper 170 cm of the upper profile. Within the 1650 trees/ha treatment, the trees utilize water to a depth of at least 270 cm. Tree form was influenced by tree density. Tree diameter decreased but height increased with tree density with the trees of largest volume produced in the 277 trees/ha-wide-spaced treatment. Variable-lift pruning was routinely applied on an annual basis from tree age 6 years, to minimize the internal knotty-core and to maximise the volume of knot-free timber produced. Pruning was virtually completed (to 6 m) after five or six annual treatments, and significant relationships between DOS (diameter over stubs) and various tree parameters were identified as predictors for determining the volume of the knotty-core. Agricultural production was assessed as net pasture production using rising-plate methodology during the major growth seasons. Trees in single rows, as in the 100 trees/ha and 277 trees/ha-wide-spaced treatments, had only a limited effect on net pasture production compared to the zone within 4.5 m from the trees in the 277 trees/ha-5 row treatment where pasture production was significantly less than in open pasture, or in the zone from 4.5 to 18 m from the tree line where there was a possible shelter benefit. Although pasture production was similar between treatments, animal production decreased with increasing tree density. Economic analyses using the FARMTREE model and progressive data from the Carngham trial showed that simulations of the agroforestry regimes at Carngham were more profitable than grazing alone using real discount rates up to 7%. The 277 trees/ha-wide-spaced regime returned the greatest net present values over the range of discount rates used. The optimum rotation length, assuming a 5% real discount rate, was 26 years. Based on the 277 trees/ha-5 row treatment, shelter benefits for agricultural production could be obtained with a distance between belts of 150 to 200 m and by leaving at least 10% of the trees unpruned. The Carngham trial represents one case study of Radiata Pine-pasture agroforestry for south west Victoria. On this basis, the data presented provides information on patterns and trends likely to be encountered in applying agroforestry to other locations in Victoria. The adoption of agroforestry requires ongoing research trials and demonstrations and the Carngham trial has been well planned and maintained and should be seen as a valuable asset for the advancement of agroforestry in Victoria.
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ItemLocal immunity in the reproductive tract of female pigs( 1993)The subject of this thesis concerns the local immune system of the reproductive tract of the female pig and the role it may play in the success of reproduction. The specific aims of this study were; (i) to localise and characterise immune cells in the reproductive tract of non-pregnant and pregnant pigs to allow a basis for an understanding of the local immune system in the reproductive tract of the pig; and (ii) to investigate the immunological influence of seminal plasma on the local uterine environment and explore the possibility of immunological involvement in the phenomenon of uterine priming to improve reproduction in gilts. Histological and immunohistochemical studies undertaken in pre-cycling and cycling gilts established the cellular basis for the local immune response in the reproductive tract. The major leukocyte cell types in the uterus of the pig are T lymphocytes, macrophages and neutrophils and their tissue migration and distribution is strongly influenced by the oestrous cycle. These studies show that the reproductive tract of the pig has a local immune system that provides an environment capable of mounting an immune response, and the various leukocyte phenotypes identified probably play an important interactive role in the cyclic cellular changes in structure and function of the endometrium. The work presented here showed that during pregnancy in the pig there are distinct changes in the presence and distribution of immune cells in the endometrium which may be evoked by exposure to paternal antigens. Further studies revealed marked differences when comparing the uterine lymph node of pregnant and non-pregnant pigs. Since the uterine node exclusively drains the uterus and the oviduct, these results provide strong evidence of a cellular immune response to pregnancy. In a study of the immunological influence of seminal components on the local uterine environment it was shown that mating with a vasectomised boar transiently induces an acute inflammatory response that includes dramatic changes in the tissue and cellular components in the endometrium. It was further revealed in vivo that seminal plasma induces the activation of lymphocytes in the uterine lymph node, while in vitro, seminal plasma fractions were shown to have a non-specific immunostimulatory effect on uterine lymph node cells. Together, these results demonstrate that pronounced immunological and physiological changes are induced by seminal plasma in utero. The results of field trials (Appendix A) indicated that pre-exposing the uterus with seminal plasma (prior mating with a vasectomised boar) can improve reproductive performance in gilts. The work presented in this thesis indicates that there is an important role for the local uterine immune system in porcine reproduction, and that the local uterine response to seminal plasma may play a key role in the success of reproduction in pigs.
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ItemThe minimisation of urea-N fertilizer losses( 1993)Disadvantages associated with the use of urea fertilizer, and which stem from the rapid hydrolysis of urea in soil include damage to germinating seedlings and young plants, and gaseous losses of urea-N as ammonia. One important approach for reducing these problems involves the application of urease inhibitors to soil in conjunction with urea fertilizer. This study was designed to investigate the ability of phenylphosphorodiamidate (PPD), N-(nbutyl) thiophosphoric triamide (NBPT) and cyclohexyl phosphoric triamide (CHPT) and nitrohumic acids derived from coal to act as soil urease inhibitors in various soil conditions. A number of preliminary experiments were conducted to determine the effects of soil water content, pH and autoclaving on soil urease activity. It was found that soil urease activity increased with an increase in soil pH from 5 to 9. Varying the soil water content caused minor effects on soil urease activity, while autoclaving caused an immediate marked reduction in activity which was regained over a 4-week period. The effects of urease inhibitors PPD, NBPT and CHPT on soil urease activity under various conditions (temperature, buffer pH and water content) were determined. An incubation experiment involving the use of nitrohumic acids (derived from brown coal) (NHA and ANH) and NBPT was carried out to compare the effects of NHA and ANH on urea hydrolysis and associated reactions in soils. In these studies, NBPT was found to be the most effective urease inhibitor in both alkaline and acid soils; PPD was more effective in acidic than in alkaline soil because this compound degraded rapidly in alkaline conditions; CHPT was more effective in alkaline soils than in acidic soils for the inhibition of soil urease activity. Degradation of CHPT tended to be rapid with low pH systems under waterlogged conditions. A kinetic study was performed by determining the rates of urea hydrolysis at different substrate concentrations and with various concentrations of urease inhibitors. The mode of action of the urease inhibitors (PPD, NBPT and CHPT) was determined to be noncompetitive. Germination tests indicated that the application of urease inhibitors NBPT, PPD and CHPT had no adverse effects on seed germination when they were applied at a concentration of less than 50 ?g/g soil. The effects of NBPT, PPD and CHPT on wheat growth, and urea-N uptake were studied in a pot experiment. Results indicated that the presence of urease inhibitors applied at 0.5-1.0% of the urea application rate did not significantly influence the dry matter production of wheat plants or N uptake by the plants. Recovery of 15N from the soil-plant systems was less where a higher rate of 15Nurea (200 mg urea-N per pot), as compared with a lower rate (50 mg urea-N per pot), was applied. The percentage uptake of applied 15N by plants was less where the higher application rate of 15N-urea to pots was made to soil. Nitrohumic acids (NHA and ANH) did not show any inhibitory effects on soil urease activity. The addition of NHA and ANH plus urea to soils did not achieve any benefits to wheat growth that could not be attributed to urea.
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ItemLogging residue assessment( 1993)A total logging residue assessment system is proposed specifically for application in the Pinus radiata D.Don. (radiata pine) plantations in South Australia and Western Victoria. The choice of line intersect sampling using pseudo-circular sample lines, believed not to have been tried before, ensures a robust sampling technique able to overcome any bias that exists in the alignment of residue following harvesting. An analysis is presented defining the bias and precision obtained from a variety of geometric sample line arrangements and sampling intensities. A cost effective residue sampling system of known efficiency can be implemented as an integral component in an overall yield regulation and control system.
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