School of Agriculture, Food and Ecosystem Sciences - Theses
Permanent URI for this collection
Search Results
1 - 10 of 45
-
ItemA comparison of cattle management systems in Kupang district, East Nusa Tenggara province, Indonesia( 1994)A program of fieldwork was conducted in Kupang District, East Nusa Tenggara Province, Indonesia for a period of three months. The aim of this study was to compare two systems of cattle rearing: the Paron (intensive) and the non-Paron (extensive) systems. Six farmers from extensive and 38 farmers for paron systems were chosen as respondents. In addition, selected characteristics were measured of the 101 cattle from the paron (36 females and 65 males) and 199 cattle from the extensive systems (134 females and 65 males). The study showed that one hundred per cent of respondents engaged in agriculture enterprises. Mixed cropping was practised and the main food crops cultivated were maize, cassava, and beans. Livestock enterprises, mainly beef cattle, were an integral part of these farming systems. This study sought to establish the growth rates for cattle within these particular systems. The data collected gave strong correlations between girth and weight, and fairly strong correlations between weight and age, weight and value, and age and value. Under village conditions growth rates are quite slow, characterised by relatively fast growth in the early stages (0-9 months) and reducing thereafter (> 12 months). Both male and female paron cattle grew more quickly than those on the extensive system. A major significant input factor determining profitability is labour and, particularly, labour used to feed the cattle. The paron system required more labour to supply fodders but fattened animals for two years (from 200 to 300 kg), while the extensive system required at least five years to reach the preferred weight (150 to 300 kg). Financial analyses used Gross Margin analysis (Cash Gross Margin and Imputed Gross Margin) as proxies for profitability. Various constraints deter the productivity of the two systems: lack of fodders and water availability resulting from unpredictable rainfall, as well as total availability of labour. It is suggested that there is sufficient way available in the paron system to boost profitability, through increasing growth rate. Currently, this averages some 180 g per day over the fattening period. Improving this through better feeding management will increase profitability, depending upon the additional labour required. A series of limits to these changes is presented.
-
ItemA simulation study of nitrogen fertilizer management strategies for wheat crops in North-West Victoria( 1994)This study addresses the issue of nitrogen fertilizer application in wheat crops under variable climate in the dryland Mallee and Wimmera districts of north-west Victoria. A crop simulation model is used to determine the response of crops to various management strategies over a number of years, using generated weather data characteristic of the study area. In the first stage of the study, the performance of a weather generator is tested. for accurate representation of weather data at a range of sites so that it can then be used to provide daily weather data for input to crop models. A weather. generator which requires only monthly weather statistics as input was tested (SIMMETEO). It overpredicted the annual number of wet days and rainfall by less than 6% of annual rainfall, which would cause small errors in crop simulations results. Generated and observed mean monthly temperatures were not significantly different. Mean monthly solar radiation was underestimated by up to 2.8 MJm-2day-1. This was found to be mostly related to the prediction of solar radiation on wet days and a solution has been suggested for sites in southern Australia. A method for the estimation of mean, monthly solar radiation from latitude was successfully tested and this can be used to provide input data for the weather generator at sites where long-term data for solar radiation are not available. The weather generator was found suitable, for use with crop simulation models in the temperate wheat-producing areas of the Australian wheat belt, where it performed better than in the tropics. In the second stage of the study the performance of a crop simulation model was tested in north-west Victoria. The CERES-Wheat-N model was tested using data gathered from commercial crops with various nitrogen fertilizer treatments from two farms over two gears at Donald and Warracknabeal. Crop growth was overestimated early in the season, which also caused the overestimation of nitrogen uptake, especially in the fertilized treatments. Soil moisture was often underestimated towards the end of the season. Nevertheless, grain yields (range; 0.6-3.7 t ha-1) were better predicted (r2:0.79) than these crop growth components and reflected known crop responses to fertilizer application and rainfall variation. The CERES-Wheat-N model requires further testing in dryland agriculture in Victoria but it can presently provide valuable information for the management of wheat crops. The performance of the model in this test is discussed in relation to other studies reported over a wider range of sites and environments. In the final stage of the study SIMMETEO and CERES-Wheat-N were.used.to examine the response of wheat crops in north-west Victoria to nitrogen fertilizer application under variable rainfall, associated with El Nino-Southern Oscillation (ENSO) and anti-ENSO episodes. These simulations were run for three sites in the Wimmera and Mallee, namely Donald, Horsham and Ouyen. Wheat production was simulated for a range of combinations of soil type, sowing date and fertilizer application over 50 years of generated weather data typical of overall, ENSO and anti-ENSO years. Simulated grain yields ranged from 0.2-3.8 t ha-1 at Ouyen, 0.3-3.8 t ha-1 at Donald and 2.3-3.8 t ha-1 at Horsham, without any applied fertilizer. The results for each combination were summarised, as exceedence probability curves for yield. These provide information about the probability of yield exceeding a certain level over the climatic range at the site. The results indicated that wheat variety Matong produced die highest yields when sown in May compared to June and July, given that frost damage at flowering is not considered. The highest yields occurred on the heavy clay soil at Horsham, followed by the grey-clay loam at Donald and the sandy loam at Ouyen. Crops on these soils also showed varied response to nitrogen application, mostly dependent on soil moisture during the season. Crop yields were higher in anti-ENSO years and lower in ENSO years, compared to overall years. Yield response to rainfall variability was marked on the sandy soil and the clay loam but not on the heavy, clay which had sufficient soil moisture to support crop growth, even in ENSO years. Applied nitrogen caused yield reductions in some ENSO years, sometimes seen as a cross-over of exceedence probability curves. The presentation of the simulation results as exceedence probability curves provides information to help decide how much nitrogen can be safely applied to achieve a particular yield with a specified risk of crop failure. Thus, wheat growers are able to identify a fertilizer management strategy that will give the most benefit in the long run, depending on the economics of production on individual farms and their attitude to risk. This study has demonstrated the potential value of using crop growth models and weather generators in crop management and has also contributed towards identifying areas in which research is required to improve the potential for the practical application of these simulation techniques.
-
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.
-
Item
-
ItemA microcomputer application of the FORest PLANning (FORPLAN) model to Australian Forestry( 1994)The FORest PLANning model (FORPLAN) has been studied and applied to Australian native forests since the late 1980s. One of the most successful and typical applications of FORPLAN to Australian native forests is the Otway Forest Management Planning Project developed by the co-operation of the Department of Conservation and Natural Resources Victoria and the Centre for Resource and Environmental Studies, Australian National University. This FORPLAN model was implemented on a VAX mainframe computer system. However, FORPLAN models can also be implemented on a PC computer. A PC version of FORPLAN has recently been developed by the Land Management Planning Systems Section, USDA Forest Service, Fort Collins, CO. In order to test the implementation of FORPLAN run on a microcomputer system, a FORPLAN model was developed for the Upper Barwon forest, which is one of ten management units of the Otway forests, based on an integrated multiple-use management approach. For this purpose, both a knowledge of linear programming techniques, and a knowledge of how to implement and utilize FORPLAN on a PC computer are required. The acquisition and application of such knowledge using data consistent with the original Otway FORPLAN model forms the subject of research described in this thesis.
-
Item
-
ItemAcute prenatal androgen treatment in sheep( 1994)The steroid environment of the cell nucleus in differentiating mammals is a major determinant of subsequent cellular function. The exogenous manipulation of this environment has resulted in permanent changes in metabolism, behaviour, reproduction, endocrinology and growth. The experiments described in this thesis suggest that an acute exposure to exogenous androgen, established as an intramuscular depot in the gravid ewe, can effect these changes. The growth responses resulting from acute prenatal androgen treatment (APAT) are similar to those reported for chronic androgenization.The undesirable side effects of androgenization, e.g. reduced birthweight, deformed external female genitalia and masculine urination posture, can be avoided with APAT. The literature and the experimental data indicate that mammalian development is strongly influenced by tissue steroid status. Furthermore, the literature and the experimental data suggest that both the timing and duration of the modification of mammalian developmental steroid status (MDSS) affect the response of ovine tissues to androgens. Some of the observed responses appear refractory in nature. The periods of sensitivity to MDSS manipulation differ between tissues and between species. MDSS manipulation via APAT is capable of effecting changes to tissues not normally considered sexually dimorphic, including the ovine pancreas, liver, brain, kidney, bone and wool follicle.
-
ItemEvaluating community involvement in revegetation( 1994)As community awareness of the effects of land degradation has increased, groups of volunteers have formed to return native vegetation to the Australian landscape. Community involvement in revegetation expands the economic, social and environmental impacts of such projects. The research reported in this thesis aims to develop an evaluative framework for assessing such impacts for community-based revegetation projects in central Victoria. From this general aim, a specific set of research objectives were developed. They were: 1) To gain an understanding of land degradation and describe the development of community involvement in revegetation from an historical perspective. 2) To define 'revegetation', 'community', and 'government support' as key terms of reference; and hence projects eligible for the study. 3) To briefly review literature describing the terms social impact, economic impact and environmental impact. 4) To review literature investigating techniques for evaluating these impacts, with specific reference to revegetation projects and projects involving volunteers. 5) To identify the types of groups and structures involved in community-based revegetation in metropolitan Melbourne and rural central Victoria. 6) To categorise and describe the broad impacts of these revegetation projects. 7) To select three groups for investigation on a case study basis. 8) Develop a set of criteria appropriate for the evaluation of community-based revegetation. 9) To evaluate the case study groups using these criteria and discuss the strengths and weaknesses of the framework. 10) Based on the research findings make general recommendations regarding the community-based revegetation movement. The review of the literature revealed decreases in agricultural productivity and moves by land managers to counter these losses with conservation measures. Revegetation was one such measure that had the greatest net social benefit when it was part of potentially sustainable land use system. Further investigation of the literature failed to reveal techniques specifically developed to evaluate the range of impacts associated with community-based revegetation projects in Australia. Baseline data were collected at 44 rural and 35 urban revegetation sites by personal interview. Multiple regression analysis was used to identify the factors which influenced plant survival. The major objective for revegetation of urban sites was improvement of amenity and scenic values. Planning of the revegetation projects generally was primitive and once established, some 70 per cent of sites relied on government. organisations for maintenance. Volunteers had contributed more hours than government officers to establish approximately 347,100 plants. The major factors influencing plant survival were season, planning, use of indigenous plants, plant protection and vandalism. The major objectives for rural revegetation were amelioration of salinity and erosion and creation of windbreaks. Planning of revegetation projects also was primitive. Rural group members had established almost 233,700 plants at group planting sites and 1,163,200 plants by individual plantings. Respondents believed lack of moisture, vermin, weed competition, insect and waterlogging had contributed to plant loss. The groups were categorised on the basis of their organisational structures. Three groups were selected for case study analysis, using Bennett and Nelson's (1975) evaluative model for community development as a framework. Performance indicators were drawn from the preliminary survey and recent evaluations of ParkCare and LandCare. Castle Creek Catchment LandCare group members were farmers who had joined the group because they were interested in better land management. Many respondents preferred to plant individually on their own farms, with availability of time as their major constraint. The group had planted approximately 25,000 trees and shrubs with 70 per cent survival rate. The combined value of volunteer and government labour, government grants and the cost of materials gave a estimate of $353,900 spent on revegetation. The ratio of Castle Creek Catchment LandCare group inputs to government inputs was 2:1. The cost per tree was calculated to be $20, the major component of which was labour costs. The second group, Sunbury LandCare group, was located on the urban fringe. As most members were hobby farmers there was division between those interested in public land and those whose priority was to revegetate their own properties. The group had established approximately 29,400 plants with 71 per cent plant survival. The value of contributions to revegetation was $236,000, with a ratio of 3:1 for volunteer inputs to government inputs. The cost per tree was estimated to be $11. At Greenlink Box Hill, an urban group, all members understood and agreed with group objectives. The group leaders were experts in the field of indigenous revegetation, so the standard of revegetation was high. The ratio of volunteer inputs to government inputs was 9:1. The group had established in the vicinity of 60,000 trees, shrubs, grasses, herbs and forbs. The cost per plant was $10. From the case studies, it was concluded that group success required a clear set of objectives which reflected member interests. Government support through grants and staff support was significant for all three groups. Officers working with the groups required technical and liaison skills. The standard of revegetation projects was linked to the constraints upon individuals and within the groups. Time, money and knowledge all influenced the level of planning, site preparation and maintenance. It appeared that the aims of shelter creation and improvement of landscape aesthetics were achievable through community-based revegetation. However, lack of monitoring of land degradation processes made it impossible to speculate upon the extent to which more complex processes such as erosion were affected. The underlying distinction between rural and urban revegetation was that most rural projects were on private land, whereas urban revegetation took place on public land. Lack of planning and explicit arrangements for follow-up maintenance, management and protection raise questions about the extent to which project objectives will be achieved in the long term. It is suggested that some of these shortcomings could be alleviated through a change in funding arrangements.
-
Item
-
ItemSoil physical and chemical properties under Casuarina cunninghamiana Miq. (river sheoak) shade trees in northern Victoria( 1994)Casuarina cunninghamiana Miq. (river sheoak) is an Australian native tree with a natural distribution throughout eastern Australia. It is one of the three Australian casuarinas being widely grown in many countries as an exotic multipurpose tree. This thesis reports on a study of soil physical and chemical properties under C. cunninghamiana shade trees in northern Victoria. The study aimed to assess whether the presence of the trees had any effect on soil properties (bulk density, organic matter and chemical properties) by comparing soil under the canopy with soil under the adjacent open pasture. The study was conducted at the Department of Agriculture Rutherglen research station which has a mean annual rainfall of 590 mm and moderately to strongly acid Rutherglen loam soil. The study involves two main treatments: under the tree canopy and under open pasture. The treatments were replicated in each quarter of the sample plot containing nine sample trees. Soil samples were collected only once for soil bulk density, organic matter and chemical properties. The results showed that the presence of C. cunninghamiana shade trees did not improve soil bulk density, organic matter content and chemical properties of the surface soil (0-15 cm depth) under the canopy. Soil bulk density and organic matter content under the canopy were not significantly different (1.12 g cm-3 and 4.44% respectively) compared with open pasture (1.19 g cm-3 and 4.07% respectively). Soil pH and total nitrogen were significantly less (pH 4.20 and 0.08% respectively) under the canopy compared with under the open pasture (pH 4.48 and 0.01% respectively). Available phosphorus and exchangeable potassium levels under the canopy (2.09 ?g/g and 4.22 cmol kg-1 respectively) were not significantly different compared with open pasture (0.773 .Lglg and 4.88 cmol kg- I respectively). The lack of improvement in soil bulk density and nutrients under the canopy is probably due to the inherent acidity of the soil. This may make conditions unsuitable for litter breakdown and nitrogen fixation. Low rainfall and seasonal flooding of the study site may also be influencing these soil properties. The results demonstrate that the potential of C. cunninghamiana to improve soil properties may be variable depending on the site conditions.
- 1 (current)
- 2
- 3
- 4
- 5