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| Registros recuperados: 66 | |
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| Marsh, Sally P.; Pannell, David J.. |
| In most states of Australia, agricultural extension policies and practices have increasingly been based on considerations of private/public goods, user pays and cost recovery. In addition, the delivery of extension has been strongly influenced by changing administrative structures and a change in the paradigm within which the extension community operates. These changes have had major impacts, including more extension being delivered by the private sector. There are positive aspects to the changes and, for some issues, they are appropriate. However, we have a number of reservations, particularly about the effectiveness of current extension systems in assisting the adoption of complex environmental and farming system technologies. |
| Tipo: Journal Article |
Palavras-chave: Teaching/Communication/Extension/Profession. |
| Ano: 2000 |
URL: http://purl.umn.edu/117854 |
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| Pannell, David J.. |
| A biologically realistic model of crop yield response to herbicide application is presented. It includes functions for weed mortality from herbicide application and yield loss due to surviving weeds. The optimal herbicide rate and two types of decision thresholds are derived theoretically and illustrated with empirical examples. Responses of the various decision criteria to changes in parameters are also examined theoretically and empirically. A multidimensional threshold for weeds based on weed density and weed-free yield is presented. The issue of farmers using other than officially recommended herbicide rates is discussed. |
| Tipo: Journal Article |
Palavras-chave: Risk and Uncertainty. |
| Ano: 1990 |
URL: http://purl.umn.edu/22352 |
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| Pannell, David J.. |
| Batterham (1987) described a computer program which eases entry of mathematical programming data. Users of the program first use a text editor to enter data in a relatively efficient format, which the program then converts into MPS format as required by most mathematical programming solution programs. Alternatively the program can read and convert data from a microcomputer spreadsheet data file. This note is a description of a microcomputer program which has advantages over each of these procedures. The program, GULP (General, User friendly Linear Programming), is an integrated package of procedures for data entry, matrix printing and model solution. GULP has particular advantages for education and has been used in a number of courses in Western Australia. |
| Tipo: Journal Article |
Palavras-chave: Research Methods/ Statistical Methods. |
| Ano: 1988 |
URL: http://purl.umn.edu/12569 |
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| Gorddard, Russell J.; Pannell, David J.; Hertzler, Greg. |
| The presence of weeds which have developed resistance to chemical herbicides is a problem of rapidly growing importance in Australian agriculture. We present an optimal control model of herbicide resistance development in ryegrass, the weed for which resistance is most commonly reported. The model is used to select the optimal combination of chemical and non-chemical control measures taking account of the trade off between short term profits and the long term level of herbicide resistance. Results indicate that given the threat of resistance there are benefits from integrating a combination of chemical and non-chemical control measures. The optimal strategy is found to include a declining herbicide dosage as resistance develops, with compensatory increases... |
| Tipo: Journal Article |
Palavras-chave: Research and Development/Tech Change/Emerging Technologies. |
| Ano: 1995 |
URL: http://purl.umn.edu/22858 |
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| Pannell, David J.. |
| The Natural Heritage Trust and the National Action Plan for Salinity and Water Quality were major national policies focused on land and water degradation and nature conservation in Australia. These programs fell a long way short of achieving their stated goals. It is proposed that to be able to spend their considerable public funds in cost effective ways, they would have needed a number of particular characteristics. Among other things, they needed to prioritise investments well, consistent with an appropriate role of government, and based on analyses that integrated good quality bio-physical and socio-economic information. They needed to select policy mechanisms that would be appropriate for the circumstances. The incentives created by program rules and... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Policy evaluation; Policy mechanism choice; Policy implementation. |
| Ano: 2009 |
URL: http://purl.umn.edu/47935 |
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| Marsh, Sally P.; Curatolo, April; Pannell, David J.; Park, Geoff; Roberts, Anna M.; Alexander, Jennifer. |
| Investment in natural resource management (NRM) by regional organisations in Australia has been widely criticised for failing to achieve substantial environmental outcomes. The Investment Framework for Environmental Resources (INFFER) is a tool for developing and prioritising projects to address environmental issues such as water quality, biodiversity decline, environmental pest impacts and land degradation. INFFER is an asset-based, targeted, and outcome-focussed approach to environmental investment, and as such is a very different and more rigorous approach to prioritising possible environmental projects than used previously by most catchment management organisations (CMOs) in Australia. From 2008 to 2010 INFFER has been trialled with CMOs. Evaluation... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: NRM investment planning; NRM investment prioritisation; Regional catchment management organisations; NRM policy; Environmental planning; Environmental prioritisation; Environmental policy; Environmental Economics and Policy; Research and Development/Tech Change/Emerging Technologies; Q50; Q58. |
| Ano: 2011 |
URL: http://purl.umn.edu/100584 |
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| Doole, Graeme J.; Pannell, David J.. |
| Simulation models are valuable tools in the analysis of complex, highly constrained economic systems unsuitable for solution by mathematical programming. However, model size may hamper the efforts of practitioners to efficiently identify the most valuable configurations. This paper investigates the efficacy of a new metaheuristic procedure, compressed annealing, for the solution of large, constrained systems. This algorithm is used to investigate the value of incorporating a sown annual pasture, French serradella (Ornithopus sativa Brot. cv. Cadiz), between extended cropping sequences in the central wheat belt of Western Australia. Compressed annealing is shown to be a reliable means of considering constraints in complex optimisation problems in... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Combinatorial optimisation; Crop rotation; Simulated annealing; Research Methods/ Statistical Methods; C63; Q15. |
| Ano: 2007 |
URL: http://purl.umn.edu/10438 |
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| Pannell, David J.; Ewing, Michael A.; Ridley, Anna M.. |
| Dryland salinity is one of the most prominent and intractable problems facing farm managers in the extensive non-irrigated farming systems of southern Australia. The issue was ignored by policy makers until late in the twentieth century, but is now the sole or partial subject of government programs with budgets totaling several billion Australian dollars. Salt occurs naturally at high levels in the subsoils of most Australian agricultural land. As a result of clearing native vegetation, groundwater tables have risen, mobilising the salt and causing adverse impacts to farmland, infrastructure, water resources, and biodiversity. The main action required to prevent groundwater tables from rising is establishment of perennial plants, either herbaceous... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Farm Management; Resource /Energy Economics and Policy. |
| Ano: 2003 |
URL: http://purl.umn.edu/24310 |
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| Pannell, David J.; Kingwell, Ross S.; Schilizzi, Steven. |
| Bugs are an unavoidable aspect of mathematical programming (MP) modelling. In this paper we discuss the prevention and diagnosis of bugs in MP models. The topic is rarely addressed in the literature but is crucial to the success of modelling projects, especially for large models. We argue that finding a bug and understanding unexpected results (whether or not due to a bug) are very closely related activities. We identify different types of bugs and suggest practical strategies for dealing with each. Adopting procedures for prevention of bugs is essential, especially for large models. We outline the prevention strategies we have adopted and found successful for the MIDAS and MUDAS models. |
| Tipo: Journal Article |
Palavras-chave: Research Methods/ Statistical Methods. |
| Ano: 1996 |
URL: http://purl.umn.edu/12306 |
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| Pannell, David J.. |
| A broad range of information relevant to salinity is reviewed in order to critically evaluate existing and prospective policy responses. The review includes issues of hydrogeology, farmer perceptions and preferences, farm‐level economics of salinity management practices, spill‐over benefits and costs from salinity management, and politics. The technical challenge of preventing salinity is far greater than previously recognised. The farm‐level economics of currently available management practices for salinity prevention are adverse in many situations. Off‐site benefits from on‐farm practices are often small and long delayed. Past national salinity policies have been seriously flawed. While current policy proposals include positive elements, they have not... |
| Tipo: Journal Article |
Palavras-chave: Land Economics/Use. |
| Ano: 2001 |
URL: http://purl.umn.edu/117725 |
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| Kragt, Marit Ellen; Pannell, David J.; Robertson, Michael J.; Thamo, Tas. |
| This paper has been published in a peer-reviewed journal as: Kragt, M.E., Pannell, D.J., Robertson, M.J. & Thamo, T. (2012) Assessing costs of soil carbon sequestration by crop-livestock farmers in Western Australia, Agricultural Systems, 112: 27-37. DOI: 10.1016/j.agsy.2012.06.005 |
| Tipo: Working or Discussion Paper |
Palavras-chave: APSIM; Bioeconomic Modelling; Carbon Farming; Climate Change Mitigation; MIDAS; Soil Carbon Sequestration; Agricultural and Food Policy; Crop Production/Industries; Environmental Economics and Policy; Farm Management. |
| Ano: 2011 |
URL: http://purl.umn.edu/109247 |
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| Registros recuperados: 66 | |
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