School of Agriculture, Food and Ecosystem Sciences - Theses

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    Spring water use in raised bed cropping
    Clark, Gary John ( 2004)
    Cultivation of heavy clay soils with the application of gypsum is often used to improve root exploration of the soil profile and hence more efficient use of the soil resource to enable higher grain yields of cereal crops. Soils in south-western Victoria are derived from tertiary basalts with high clay content and often dispersive subsoil. Cereal crops grown on these soils are prone to waterlogging. Waterlogging has been overcome with the use of raised beds. The hypothesis was that the heavy subsoil restricted rooting depth and hence efficient water extraction from the soil profile, particularly in the grain filling period during spring. Deep cultivation of the soil was proposed to overcome subsoil limitations. This study has compared the use of deep ripping, with and without the use of gypsum, to the use of direct drill techniques. Soil water use and plant root density have been compared for the different cultivation treatments. Soil water use indicated that the use of direct drill, compared with deep ripping, was favoured during years with dry autumn or delayed autumn breaks. Surface soil water was conserved in the direct drill treatments. The use of deep ripping, with and without the use of gypsum did not significantly increase the rooting density to a greater depth than direct drill. Furthermore the deeper roots failed to access soil water to improve grain yield compared with direct drill treatments. An increase in grain yield, with the use of deep ripping, was recorded in a year of above average rainfall in the growing season. The addition of gypsum, when deep ripping, provided no additional benefit to grain yield in the above average rainfall year.
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    The economic evaluation of forage research results
    Gaffy, Joseph ( 2004)
    Three economic analyses were conducted on the results of dairy forage production experiments undertaken in Victoria. The first analysis investigated the level of pasture production increases that would have to be achieved to warrant the investment in different soil modification options. This analysis took pasture production data and using a computer program "UDDER" (Larcombe 1990) generated farm data which was then applied to development budgets. The increase in pasture growth rate required was such that it is unlikely that investment in the soil modification systems tested here will produce a satisfactory return on investment. The second analysis investigated the use of different pasture species combinations on a dairy farm in northern Victoria. A linear programming model was developed that balanced the energy requirements of the milking herd with the energy supplied from pasture and supplements. The results showed that the most profitable mix of pasture depended on the energy supply profile of the pasture and the requirements of the herd. The proportion of autumn and spring calving cows in the herd in part determined the most profitable pasture mix. The effect of grazing management on profit was the subject of the third study. A farm model was constructed that balanced the energy, protein and neutral detergent fibre requirements of the milking herd with that supplied by pasture and supplements and optimised operating profit. The results of a grazing trial conducted in south-west Victoria were entered into the model and the operating profits for each treatment compared. The results suggested that while Operating profit was related to total pasture consumption, the timing of the pasture consumption impacted on operating profit. The results also suggested that grazing frequency may have affected operating profit more than grazing intensity.
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    A study of horse ownership and management in Victoria, Australia
    Pearson, Naomi Yvette ( 2003)
    The welfare of horses is becoming an increasingly important issue in many parts of the world, particularly for horses used for recreation. This is because recreation is the principal use of horses in many countries today, in contrast with the largely working role they have played in the past. Animal welfare organisations and government enforcement bodies are finding it increasingly difficult to handle the number of complaints received about horse welfare problems. In Victoria, Australia, the number of horse welfare problems investigated by the Royal Society for the Prevention of Cruelty to Animals (RSPCA) remains extremely high, and significant time and resources are utilised in dealing with these problems. However little is known about the type of horse welfare problems that are occurring, or about the potential causes of these problems, such as the owners of such horses. In order to prevent horse welfare problems in the future, an understanding of the type and prevalence of the problems and their potential causes is crucial. The aim of this thesis was to identify the type and seventy of horse welfare problems inspected by the RSPCA in Victoria, and to identify the characteristics of the horses' environment that were related to their welfare. Additionally, a survey was conducted of 100 owners that were inspected by the RSPCA throughout Victoria, of which 70 had horse welfare problems and 30 did not, to examine the relationship between some attributes of these owners, and horse welfare. An additional 30 horse owners that, were members of adult riding clubs were surveyed, to provide an alternative control group. Results found that the most prevalent horse welfare problem was poor body condition and that most of these problems were rated as moderately severe by the author. Other problems that occurred were overgrown hooves, illness, founder, untreated injury and permanent tethering. Of particular concern was that the number of severe cases found was much larger than expected. The only environmental characteristic that was associated with reduced horse welfare was a lack of pasture. There were a number of differences between the horse owners that were members of adult riding clubs and owners with horse welfare problems that were inspected by the RSPCA. Owners of horses with welfare problems had a lower level of education and income, more owners were male, more lived closer to the city, less were married or in a defacto relationship, and more had less knowledge about horse management and less commitment to horse ownership. These owners also believed that horses made good companions and that less commitment was needed in horse ownership, and mainly used their horse(s) for companionship and/or pleasure riding, rather than for competition. Additionally, attributes of owners with a horse welfare problem that were specifically associated with increased severity of the welfare problem were lack of commitment to horse ownership, the belief that horses made good companion animals and were difficult to care for, lower education, and living in metropolitan Melbourne or in the outer-fringes (within 50km of the city). Of particular interest was that over half of the owners with horse welfare problems had never had riding lessons and did not frequently read horse literature, and nearly three quarters of these owners were not members of any horse clubs or organisations. The results of this project provide a valuable insight into the problem of horse welfare and thus the type of strategies that are required to prevent horse welfare problems in future.
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    Economic evaluation of vegetable crop production in the Goulburn Valley region : using profit maximisation and optimal crop combination approaches
    Top, Baki Murat ( 2002)
    The vegetable industry in the Goulburn Valley Region has strengths, including the availability of technology and expertise, growing markets, a clean production environment, water availability and the relatively low cost of energy resources. Availability of the use of developed methods, techniques and equipment from transplanting machinery to post-harvest handling and storage facilities are also strengths of the vegetable industry in the Region. These advantages could enable the growers to readily incorporate other vegetable crops into their cropping practices. This type of diversification may well be beneficial both from economic and agronomic standpoints. The overall aim in this thesis is to make recommendations on optimal crop combinations, which can maintain farm profitability of vegetable growers in the Region. Incorporated within this overall objective, three major methods were undertaken in this study to find out options to better farm management. First, the economic aspects of some major vegetable crops are analysed and their economics and productivity are compared. The gross margin analysis of five selected vegetable crops are used to compare the different management practices, timing of operations and different returns. The gross margins per hectare of each crop were also estimated to provide decision-makers with a tool for comparative analysis of activities in a similar environment on their farm. The advantages and disadvantages of single cropping with multi cropping practices, by identifying practical possibilities that could enable growers to better utilise their farm and equipment by crop diversification, was also compared in this part. Second, to investigate economic rationality of growers production practices, using a Cobb-Douglas production function. The production function provides ideas about relationships between production inputs and output. Decision-makers can use the production function analysis to investigate returns to scale, which can show how the scale of production (output) will change when the decision-makers change the factors (inputs) of production. The gross margin technique assumes a linear relationship as an activity is expanded, ie. If the area of crop is doubled, it is assumed that the gross margin for the extra hectares will be the same as for the original area. This is not always so, as there can be a diminishing returns effect as the activity is expanded. While in many cases it is reasonable to assume a linear relationship when planning to increase the area, the grower and his decision-maker should keep the possibility of diminishing returns in mind as the activity is expanded (Makeham and Malcolm, 1986). This information can be obtained from the production function analysis. Third, a linear programming model was developed in this thesis and it was used to solve a particular planning problem (profit maximisation) in a hypothetical situation. Growers must repeatedly make decisions about what crops to produce, by what method, in which season or time periods, and in what quantities in any multiple cropping system. They have to make these decisions subject to the existing farm physical and financial constraints to get the best or "optimal" solution to their problems. The linear programming model's results were also related to production and price functions. This was done to provide the decision-makers with a logical structure for understanding the farm profit related problems and finding how crop quantity and price can be affected. In order to assess the objectives the following two hypotheses were also tested. 1. As an alternative crops whether the production of capsicum, zucchini, broccoli and cabbage were satisfactory crops according to tomato in the Region, and 2. Whether there were any new practices, which could be used by growers to adjust to producing those vegetables. The results show that the vegetable industry has potential to achieve better utilisation of the farm resources and thus increase the farm profitability. Growers should be aware of the production factors that will enable them to increase their competitiveness, and must structure themselves to better utilise them. Therefore, some new practices such as diversification or double cropping practices, using the same growing materials in the same paddock continuously, should be considered. Diversified systems or multi cropping would reduce financial risk and provide protection against drought, pest infestation or other natural factors that can limit the farm production and profitability. However, diversification may increase risk for various reasons including capital costs of highly specialised equipment, associated economy of scale issues and possible lack of expertise required for increasingly specialised production systems. In addition, the possibility that related products such as summer or winter vegetables may be in ample or scarce supply at the same time, and subject to the same price cycle. The major outcome from this research is that there are possibilities and opportunities for the growers to sustain their farm profitability and productivity in the Region. This could be achieved by identifying potential objectives (minimise or maximise something) to find the optimal solution to their farm problems.
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    Development of management practices for control of Rhizoctonia solani Kuhn (AG 8) in Victorian cereal crops
    Henry, Francis John ( 2003)
    The studies reported in this thesis showed that Rhizoctonia solani Anastomosis Group 8 was widespread in all Victorian cropping soils. In barley, the incidence of Rhizoctonia root rot at anthesis, was 54%, 70%, 93% and 97% on grey clay, red clay, red duplex and Mallee soils respectively. In wheat, the incidence at anthesis was 70%, 69%, 74% and 68% on the grey clay, red clay, red duplex and Mallee soils respectively. Over the years 1990-1992, the disease caused an average grain yield loss of 12% in barley and 5.5% in wheat, with the highest losses occurring on the Mallee and red duplex soil types. It was shown that farmers were not achieving adequate control of Rhizoctonia root rot, and that cultivation per se was not effective in reducing its incidence or severity. In barley, the average incidence of Rhizoctonia root rot at anthesis was over 90% in crops grown on Mallee or red duplex soil types, regardless of tillage practice. Other researchers have reported tillage to reduce the incidence and severity of Rhizoctonia root rot. In wheat, incidence at anthesis was over 60% in crops grown on all soil types, regardless of tillage practice. The distribution of R. solani (AG 8) was related to both biological and physical factors of the different soil types. The disease was more severe in soils where organic matter levels were low, and there was little natural suppression of the fungus by other organisms. It is postulated that increasing the amount of organic matter in the soil would lead to a higher microbial mass in the soil and the resulting competition would reduce the survival of R. solani (AG 8). The root and hypocotyl rot strain of R. solani AG 2-1 (ZG 6) that occurs on pulses, was found on wheat and barley roots, and the cruciferous strain AG 2-1 (ZG 5) was found on both wheat and lupin roots and hypocotyls. These strains of R. solani could therefore increase under intensive rotations in the Wimmera and North-Central areas. Results from the field experiments demonstrated that the use of "cultivate deep - sow shallow" methods of crop establishment in conservation farming systems are as effective in controlling Rhizoctonia root rot, as traditional cropping systems. However, control could be improved with a strategic cultivation in years with an early autumn break to maximise destruction of the fungus networks of the fungus in the soil. Deep banding fertiliser, 5-10 cm under the seed, with the depth-modified combine at sowing reduced the severity of Rhizoctonia root rot and increased grain yield in 5 out of 9 field experiments. This indicates that deep banding fertiliser is viable option for farmers, and further studies in this area with a range of fertilisers would confirm these results. As a consequence of the studies represented in this thesis it was concluded that further research into the management of R. solani (AG 8) should concentrate on developing host plant resistance with transgenes. Other diseases: Cereal cyst nematode (Heterodera avenae) was detected in all soil types, and caused annual yield losses of 6.0% in barley and 6.6% in wheat. The nematode was most common on Wimmera grey clays, and was recorded for the first time on the red duplex soils of the North-Central district. Further studies are required to determine if changes in cultural practice through the use of gypsum, stubble retention and direct drilling to improve soil structure will increase the incidence of cereal cyst nematode. The re-introduction of susceptible cultivars into the Wimmera could lead to major outbreaks of cereal cyst nematode. Take-all (Gaeumannomyces graminis var. tritici) was detected in crops growing on all soil types. Yield losses were 4.9% in barley and 5.1% in wheat, and the pathogen was most prelevent in Mallee and red duplex soils. It is recommended that further studies should be undertaken to determine whether the adoption of conservation farming practices to improve soil structure will reduce the incidence and severity of take-all.
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    A farm management economic analysis of future dairy systems in the Goulburn Valley
    Nesseler, Richard K ( 2002)
    Case studies were used to analyse the organisation and management of two irrigated dairy farm businesses. In particular, the focus was to . identify the economic' aspects of current and future farming systems in the Goulburn Valley. The approach involved focusing on farmers, the farm business, and the specific details of the farm system that farmers were managing. A whole-farm perspective was relevant as it provided details of the farm system and farmer characteristics that substantially influence how they respond to market changes. The economic 'analyses revealed that theoretical concepts often match the practical management of irrigated. dairy businesses. Also, relatively simple farm management budgets, which capture the full effect on management of the whole farm system from development, have a useful role in providing farmers with effective information about the medium-term growth opportunities on irrigated dairy farms in the Goulburn Valley. From these results it can be concluded that 'it is not what you do, but how you do it' that primarily determines the level of success in achieving goals.
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