School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemA systems analysis approach to drought reserves in the Hamilton region( 1971)Following a discussion of drought strategies available to the grazier, one particular strategy, the holding of drought fodder reserves, is examined in detail. The study estimates the least-cost fodder reserves for a range of stocking rate-pasture production regimes in the Hamilton region. The amount of hay feeding required on any stocking-pasture regime is determined from a simulation model of the grazing complex. In this model, three levels of pasture production are stocked at rates ranging from one to ten wethers per acre. The pasture production assumed ranges from "excellent" (i.e. equivalent to the Hamilton Research Station pastures which produce about 10,000 lb. dry matter per annum) to "poor" (35% less). The climatic inputs into the grazing model are the date of Autumn break, for which a formula is derived, and the June to October rainfall. The pasture sub-model is specified and used to derive the pasture which is "grown" in the grazing model. The sheep aspects of the model are reviewed in detail to derive the relationships which are used in the next set of four sub-models in which animal intake is simulated and liveweight changes determined. This set of four sub-models provides for the four situations of animal intake which may be met. These are: The intake of green pasture alone (i.e. all pasture grown after the Autumn Break); the intake of hay alone; the intake of hay and green pasture together; the intake of hay and dry pasture (pasture remaining when the Autumn Break occurs and dry pasture alone which are handled in the same sub-model) The grazing model was validated for the years 1965-67 using data from the Pastoral Research Station, Hamilton, and showed good agreement for all three years simulated, one of which featured a severe drought. Drought feeding requirements (hay) are determined for each of the years 1879 to 1967 and for the ten stocking rate-pasture production regimes, using specific hay feeding rules. These rules, which aim at sheep survival, do not attempt to specify optimum feeding rates per sheep, and any change in them could significantly alter the drought requirements for any of the regimes studied. Furthermore, the estimates are Lased on the assumption that all sheep are fed through the drought. A pre-drought strategy which permitted the sale of certain classes of sheep at some stage during drought would entail lower feed requirements and might have a lower expected cost, especially at high acquisition costs for feed and low replacement costs for sheep. An inventory analysis is then undertaken, based on a 12 month planning period, which utilises the hay feeding probabilities generated in the grazing model, and provides estimates of the least-cost hay reserve. In contrast to previous studies, the price of hay is related to drought length in calculating the penalty cost of inadequate reserves. The effects of varying several parameters of the inventory model are then examined. The parameters varied are hay costs ($4, $10 and $16 per ton), interest rates (7%, 20% and 50%), and salvage values, and these vary in association with the parameters varied in the grazing model (stocking rate, pasture production and the area closed for hay). At the intermediate values for pasture production and hay cost and a 7 per cent per annum interest rate, the minimum-cost reserve rises sharply, from 2 bales per acre at 2 wethers per acre, to 4.5 bales per acre at 3 wethers per acre, 8 bales per acre at 4 wethers per acre, and 15 bales per acre at 5 wethers per acre. The minimum-cost reserve was found to be relatively insensitive to changes in acquisition costs, except at low stocking rates, where a change in reserve of one or two half-bales per sheep was common as acquisition cost varied over the three levels. The effect of interest rates was also examined for the average pasture regime. On the lowest level of hay acquisition cost, ($4 per ton) increasing the rate of interest from 7 to 50 per cent caused reductions of only one half-bale per sheep. However, at high acqusition cost ($16 per ton) raising the interest rate to 20 per cent resulted in a considerable reduction in the minimum-cost reserve, especially on the lower stocking rates, and raising the interest rate to 50 per cent made holding fodder reserves uneconomic for any stocking rate. One measure of the risk in holding various levels of fodder reserve is the standard deviation of the total expected cost. As expected, it was found that this declines as the reserve is expanded to the maximum ever required. However, only a small reduction in standard deviation results from expanding the reserve beyond the minimum-cost level. Finally, estimates were made of the income-maximising stocking rate for each level of pasture production and hay cost, with the wool price at 30, 40 and 50 cents per lb.. At the intermediate values for pasture production (8,000 lb. D.M.) and hay cost ($10 per ton), and with wool at 30 cents per lb. net, the income-maximising stocking rate was 3 wethers per acre. Each increase of 10 cents per lb. in the wool price was generally associated with an increase of one or two wethers per acre in the income-maximising stocking rate. An increase of 2,000 lb. D.M. (from "average" to "excellent") in average annual pasture production was generally associated with an increase of one wether per acre in the income-maximising stocking rate. A reduction of 1,500 lb. from "average" to "poor" pasture. production reduced the income-maximising stocking rate by about one wether per acre. Increasing the hay cost from $4 to $10 per ton reduced the profit-maximising stocking rate by one wether per acre for all combinations of pasture production and wool price examined. However, a further increase in acquisition cost from $10 to $16 per ton only caused a further reduction in the income-maximising stocking rate at the poor level of pasture production: with average pasture production there was little change and with excellent production there was no change in the income-maximising stocking rate.
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ItemFarm size, structural change, and adjustment policy : a study of the dried vine fruit industry in Sunraysia and Robinvale( 1977)Dried vine fruit farms in Sunraysia and Robinvale were nearly all established under closer settlement schemes, with farm size averaging about 8 hectares. The present study indicates that economics of size exist up to a harvested area of about 25 hectares. This would suggest that structural change is occurring in the industry, with farms being amalgamated to take advantage of these economies of size. However, structural change in recent years has been negligible. Some of the obstacles to adjustment are examined in the thesis. They have important implications for government policy; in particular, there is a need for a Land Authority to facilitate adjustment in dried vine fruit growing regions. The thesis also considers some methodological problems in estimating economies of size, and in deriving policy proposals from such estimates. It concludes that the results of most studies of farm size, including this one, must he regarded as provisional, pending the outcome of properly designed empirical tests. It also concludes that the Paretian concept of efficiency is inadequate as a framework for adjustment policy. I would like to thank my supervisors,Mr. G.W. Edwards, Mr. N.H. Sturgess, and Dr. A.S. Watson, for their advice and encouragement during this study. I am also grateful to Mr. John Connell who colaborated on a preliminary statistical analysis (see Section 4.1.6). Acknowledgement is made to the Bureau of Agricultural Economics for the data used in the empirical sections of the thesis. I am grateful to Mrs. Sue Valiance for her excellent typing of the manuscript, and to Mr. Bill Dahl for preparing the diagrams. I was assisted financially by an A.M. White Scholarship and an R.W.S. Nicholas Scholarship. Finally, I would like to thank my wife, Jacky, for her financial support, for help in preparing the bibliography, and for her patient encouragement.
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ItemThe Victorian scallop fisheries : an economic analysis( 1978)This thesis studies the Victorian scallop industry in an economic framework. It is the first of its kind to be performed on a Victorian fishery. A static model of a scallop fishery is used to investigate whether a reduction in the size of the scallop fleet would be desirable. The implications are examined of various management schemes which would aim to maximise the net economic benefits to be earnt from scallop fishing. Fishing industries and especially those based on highly valued species such as the scallop, have a tendency to be problem industries. The Victorian scallop industry is no exception. The common. property nature of the marine fishery is the root cause of this problem. Left to their own devices fishermen will keep entering a fishery as long as there is incentive to do so. The central hypothesis of this thesis is that the amounts of capital and labour allocated to the Victorian scallop fishing industry are excessive. The common property-theory of a fishery is dealt-with in chapter 2. There a static model of the . fishery is developed through two stages. The first enables the identification of the optimal rate of exploitation given that the objective of management is to maximise resource rent. The second stage of this model enables-the identification of several different optima each according to a form of control or ownership. Consideration is also given to some models which incorporate time as a variable. Chapter 3 deals with fisheries management. It outlines those measures which may be used to control-fishing effort as well as the secondary measures which may also be necessary to control a fishery. Chapter 4 discusses the two Victorian scallop fisheries at Port Phillip Bay and Lakes Entrance. It gives background. information on scallop fishing and a history of past and present management measures. It includes an outline of the management objectives the Fisheries and Wildlife Division of the Ministry for Conservation has in mind when formulating policy. A brief description of the biology of the scallop is given in chapter 5. This is followed by the development of a yield model which. is then applied to the two scallop fisheries. The results of a cost and income survey of scallop fishermen, are reported in chapter 6 and these results are used to calculate linear cost of effort functions for the two fisheries. Chapter 7 draws together the yield and cost of effort functions to produce cost of output functions. These - functions enable the estimation of optimal amounts of effort and catch given that the objective of management was to maximise resource rent. The implications of these results are discussed in chapter 8.