School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemNo Preview AvailablePerformance recording of beef cattle in Victoria and adjacent regions(University of Melbourne, 1968)This thesis comprises four chapters. Chapters 1, 2 and 3 report scientific investigations involving performance recording of beef cattle. Chapter 4 contains conclusions and recommendations based on the investigations described in the first 3 chapters. My responsibilities in the preparation of this thesis included a detailed review of the scientific literature on subject matter pertaining to performance recording of beef cattle. This is presented in chapter 1 and this entire chapter was my complete responsibility. Chapter 2 describes the beef cattle breeding industry and the records which were available for this study. I am responsible for the contents and preparation of this chapter. Chapter 3 includes the analysis and interpretation of the records used in this study. Dr. R. G. Beilharz assisted with the statistical analysis. Chapter 4, which includes conclusions and recommendations resulting from this investigation, was entirely my responsibility.
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ItemNo Preview AvailableThe use & control of plants in Victorian irrigation & drainage systems(University of Melbourne, 1967)An account is given of the use of plants by the State Rivers and Water Supply Commission of Victoria to stabilize soils in Victorian irrigation supply channel and drainage systems. Chemical methods of controlling the growth of plants that occur naturally and create problems are also described, together with the principles that are observed when developing these methods. The importance of control of plant growth to achieve maximum channel and drain capacities, while at the same time ensuring maximum soil stability is discussed. The need for regulation of chemical usage where water supplies and irrigated crops can be contaminated is stressed. Research conducted in Victoria is described and compared with that in the U.S.A., and recommendations are made regarding the most useful avenues for future research. Publications describing various aspects of the use and control of plants in Victorian irrigation and drainage systems are attached.
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ItemNo Preview AvailableThe effect of water stress on the growth of the wheat plant(University of Melbourne, 1965)
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ItemBeef-cattle production in the Western District of Victoria : technical and economic relationships between beef cattle and sheep( 1965)Sheep-and-wool production and beef-cattle production are combined on many grazing properties in the Western District of Victoria. In the past beef cattle have generally been regarded as less profitable than sheep as a sole enterprise on a per-acre basis. In previous surveys it has been found that graziers believe that sheep and beef-cattle complement one another in a variety of circumstances because of the different effects of the two types of animal on pasture. It has also been found that sheep and beef cattle on grazing properties are frequently supplementary with respect to labour. The thesis has two main objectives. First it investigates whether the currently available analytical models based on static economic theory are adequate to solve problems of resource allocation between sheep and beef cattle grazing the same pasture. Second, it investigates whether many graziers carry beef cattle partly or solely to satisfy goals other than profit maximisation. The method of achieving the first objective was to compare the static economic theory relating to enterprise combination, and published work dealing with the problem of selecting the optimum combination of two enterprises, with the real situation existing on grazing properties carrying both sheep and beef cattle. The second objective was investigated by means or an interview survey of graziers running both sheep and beef cattle in six Western District parishes. A considerable amount of technical information about beef-cattle production in the Western District was collected in the course of the survey, and the more important points are summarised in the thesis. Of particular interest are the findings that very few graziers purchased cattle for fattening purposes, and that beef cattle were relatively more important on large properties than on small properties. It was concluded that static economic theory does not provide an adequate basis for the description of the situation where sheep and cattle graze the same pasture, or for the determination of the optimum allocation of resources between sheep arid beef cattle grazing together. Sheep and cattle graze pasture differently, and therefore different pastures result as the sheep-cattle ratio is altered. In this situation, the postulates on which the iso-resource function is based, that the shared input or inputs should remain homogeneous and constant in quantity as the outputs of the products change, are violated. Thus strictly speaking it is not possible to derive a valid iso-resource function relating the sheep and beef-cattle enterprises with respect to pasture when the sheep and the cattle graze the same pasture. However, if the changes in the pasture are disregarded, it is possible to design experiments to produce practical approximations of iso-resource curves relating sheep and beef cattle. Information obtained from graziers in this and other surveys, and the results of experiments, strongly suggest that for practical purposes it is reasonable to think of an iso-resource curve for sheep and cattle with respect to pasture as being concave towards the origin, that is, the sacrifice rate of sheep for cattle increases as more cattle are added on a sheep property. Farmer estimates and experimental evidence suggests that the marginal sacrifice rate on most properties may be lower than is generally assumed (nutritional standards imply a linear rate of eight merino whethers per 1,000 lb. steer). Almost all the survey graziers believed that the overall relationship between their sheep and their beef cattle with respect to their total feed supply over the whole year was a competitive one. Most estimated that their sheep and their cattle were complementary or supplementary with respect to pasture over a part of the year, including the Spring, and that their sheep and their cattle competed for scarce pasture at some time in the autumn and winter. The survey results showed that the most important reason for the presence of beef cattle on the survey properties was the value of cattle in controlling and utilising pasture and weed growth. However the value 0f cattle for that purpose appeared to decline as the sheep stocking rate increased. It appeared that on many properties the importance of beef cattle in pasture control was a consequence of a desire on the part of the grazier to maximise profits within the restrictions imposed by limitations on sheep numbers including the grazier's desire to limit his personal effort. Beef cattle were also frequently carried for the reason that they provided a means of stabilising income from year to year. Although the survey results tended to confirm previous findings that sheep and beef cattle are supplementary with respect to labour at certain times during the year, and that beef cattle generally require less labour per unit of return than sheep, few graziers said that they carried beef cattle for those reasons. It was concluded that substantial minority of the survey graziers did carry beef cattle partly or solely to satisfy goals other than profit maximisation. The most important of these goals was the minimisation of personal effort, which was shown not by giving labour as a reason for carrying beef cattle, but indirectly in the affirmation of the value of cattle (rather than additional sheep) in pasture control. A few graziers were motivated by a personal preference for beef cattle. In the situation where the available economic theory is inadequate to solve problems of resource allocation between sheep and beef cattle, and where a substantial proportion of graziers carry beef cattle partly or solely for reasons other than profit maximisation, there is little scope for sophisticated economic procedures. Given additional experimental data to provide indicators of probable "substitution rates", it seems that the allocation of resources between sheep and beef cattle on properties such as those in the survey can best be improved by budgeting possible adjustments.
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ItemStudies on the etiology and control of parsnip canker, caused by itersonilia pastinacae channon( 1968)In Victoria, parsnip canker is caused chiefly by Itersonilia pastinacae Channon and, less frequently by Phoma sp.. Inoculation of both fungi into parsnip roots produced typical symptoms of the disease. The morphology of the local isolates of I. pastinacae was compared with others described and the taxonomy of the genus discussed. The fungus was shown to be seed-borne, the infection being carried in plant debris contaminating the seed and also externally on the seed itself. An aerated-steam heat treatment was developed to eliminate this seed-borne infection. In field studies I. pastinacae in naturally infected roots survived at least 12 months burial in soil. When the root was mutilated by removing the stem apical meristem, to promote rapid decomposition, the fungus survival period was reduced to 6 months. In laboratory studies the fungus, impregnated in fibre glass mesh, survived 6 months burial in unsterile soil, whereas the survival period in sterile soil was at least 12 months. Survival was shown to be due to the presence of chlamydospores; mycelium and ballistospores being rapidly lysed. Chlamydospores germinated directly to form ballistospores. I. pastinacae, also had a low competitive saprophytic ability. Field and laboratory studies demonstrated that ballistospore discharge was influenced chiefly by high relative humidity, the presence of rain being more effective than dew. Spore discharge followed a diurnal periodicity, the maximum discharge occurring between 08.00 and 10.00 hr.. Low temperature, however, reduced spore discharge even at optimum R.H. Ballistospore germination studies demonstrated soil fungistasis an effect destroyed by sterilization of the soil. Germination of ballistospores was also influenced by nutrients, either diffusates from parsnip roots and leaves or by a 2% glucose solution. Strepstomyces sp. and Bacillus subtilis were isolated from soil and antagonism towards I. pastinacae exhibited. Cell-free culture filtrates of both antagonists lysed I. pastinacae while incorporation of the filtrates into media reduced the growth rate of the fungus. Sterile soil inoculated with the antagonists also lysed I. pastinacae. Foliage applications of fungicides, particularly those containing copper, reduced the incidence of parsnip canker in the field. Control was also achieved in the field by keeping the developing crowns covered with soil during the growth of the crop.
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ItemA study of pathogens associated with stunted patches and deadheads in Victorian wheat crops( 1968)Between 1959-1966 seven species of root-rotting fungi and barley yellow dwarf virus were consistently associated with stunted patches and "deadheads" in Victorian wheat crops. The fungi occurring in order of frequency were: Fusarium culmorum (W.G.Sm) Sacc., Curvularia ramosa (Bainier) Boedijn, Helminthoaporium sativum Pammell, King and Bakke, Pythium ultimum Trow var. ultimum, Rhizoctonia solani Kuhn, Ophiobolus graminis Sacc. and Fusarium graminearum Schwabe. Barley yellow dwarf virus was found each season in the higher rainfall areas of the State; in 1961 and 1965 it occurred in epidemic proportions in all districts. These organisms may be divided into three groups based upon their ability to reduce yield of wheat under controlled glasshouse experiments. (1) MAJOR REDUCTION BY: Barley yellow dwarf virus; Ophiobolus graminis; Helminthosporium sativum. (2) MINOR R RUCTION BY: Fusarium graminearum, Fusarium culmorum; Rhizoctonia solani; Pythium ultimum. (3) NO REDUCTION BY: Curvularia ramosa Ophiobolus graminie and barley yellow dwarf virus are the most important of these pathogens in Victoria. Both caused yield losses of approximately 45-60% in the field. Under controlled glasshouse conditions they caused highly significant yield losses. Five other fungi investigated caused some losses, but during the period 1959-66 were not of great economic importance. The incidence of these pathogens could be related to climatic conditions before and during the wheat growing season. (1) Highest incidence after a dry winter and wet spring: Ophiobolus graminis; Pythium ultimum. (2) Highest incidence after a mild winter and dry spring: Barley yellow dwarf virus; Fusarium graminearum; Fusarium culmorum; Helminthosporlua ; Curvularia ramosa. (3) Highest incidence when crop sown under wet conditions: Rhizoctonia solani; Pahiuta ultimum.
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ItemUse of deductive reasoning by farmers( 1965)Chapter I. Review of Literature A. Classification Into Categories Sociology requires accurate observation, systematic classification and the logical establishment of relationships. Conceptical Variable Analysis provides a method of testing a general hypothesis by testing a corresponding empirical hypothesis. For example the concept of "Progressiveness of Farmers" can have as its operational measure the adoption of Farm Practices. Types of Scales developed to provide this measure are explained and evaluated.
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