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| Registros recuperados: 15 | |
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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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| Stott, Kerry; Doole, Graeme J.; Vigiak, Olga; Kumaran, Thabo; Roberts, Anna M.. |
| Ambitious nutrient reduction targets have been set for the Gippsland Lakes, Victoria but at what cost to productive agriculture? An interdisciplinary approach is addressing this question for the Moe River catchment, a dairy-dominated catchment that is a major source of pollutants to the Gippsland Lakes. Off-farm nitrogen exports are being estimated by biophysical modellers, and economists are quantifying the impact of farming systems and agricultural practices on farm profitability. This information is assembled to form the interim profit-pollution frontier for nitrogen reported in this paper, and to calculate abatement costs. Phosphorus and sediment exports will be considered in future work. This information is intended for use in a landscape-optimisation... |
| Tipo: Presentation |
Palavras-chave: Nutrient management; Profit-pollution frontiers; Abatement costs.; Farm Management. |
| Ano: 2012 |
URL: http://purl.umn.edu/124454 |
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| Beltran, Jesusa C.; Pannell, David J.; Doole, Graeme J.; White, Benedict. |
| This paper describes a complex, dynamic simulation model that has been developed for the analysis of integrated weed management programmes for the control of annual barnyardgrass (Echinochloa crus-galli) in rice farming systems in the Philippines. Users of the model may simulate any feasible combination of 49 weed treatments options across wet and dry cropping seasons over 5, 10, 15, and 20 year periods, subject to a predetermined sequence of planting methods. The main outputs of the model include weed seed and plant densities and seasonal and annualised profit over the simulated planning horizon. Model output emphasises the substantial economic benefits associated with effective long-term weed management strategies. In addition, the most-profitable weed... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Barnyardgrass; Bioeconomic model; Integrated weed management; Rice farming systems.; Agricultural and Food Policy; Crop Production/Industries; Environmental Economics and Policy; Farm Management. |
| Ano: 2011 |
URL: http://purl.umn.edu/104637 |
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| Doole, Graeme J.. |
| Annual recruitment of the NewZealand longfin eel (Anguilla dieffenbachii) hasdecreased by 75 per cent since significant levels of commercial fishing began in the early 1970s. This motivates application of a multiple-cohort bioeconomic model to a New Zealand longfin eel fishery to investigate its optimal management and ascertain the suitability of existing regulatory policy. The use of historical harvest to calculate total allowable catch is asserted to be unsustainable based on recovery dynamics. In addition, individual transferable quota systems are argued to be fundamentally flawed for the protection of longfin fisheries because of high-grading, low-surplus production and a current lack of effective stock-assessment procedures. Area closure and the... |
| Tipo: Article |
Palavras-chave: Anguilla dieffenbachii; Area closure; Fishery management; Longfin eel; Territorial user rights; Resource /Energy Economics and Policy. |
| Ano: 2005 |
URL: http://purl.umn.edu/118586 |
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| Doole, Graeme J.. |
| Many important problems in agricultural and natural resource economics concern an intertemporal choice between alternate dynamic systems. This significance has motivated a theoretical literature generalizing the necessary conditions of Optimal Control Theory to multiple-phase problems. However, gaining detailed insight into their practical management is difficult because general numerical solution methods are not available. This paper resolves this deficiency through the development of a flexible and efficient computational algorithm based on a set of necessary conditions derived for finite-time, multiple-phase systems. Its effectiveness is demonstrated in an application to a nontrivial crop rotation problem. |
| Tipo: Journal Article |
Palavras-chave: Crop management; Multiple-phase systems; Optimal control; Crop Production/Industries; Resource /Energy Economics and Policy. |
| Ano: 2009 |
URL: http://purl.umn.edu/50082 |
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| Doole, Graeme J.. |
| Lucerne ( Medicago sativa L.) helps to prevent soil salinisation in the Western Australian Wheatbelt by reducing recharge to saline water tables. There is broad consensus, though, that it is not sufficiently profitable to motivate producers to plant it at the intensity at which considerable off-site benefits would be conferred. This paper employs a multiple-phase optimal control model to explore the value of this perennial pasture for the management of herbicide-resistant annual ryegrass ( Lolium rigidum Gaud.) in a crop–pasture rotation, given the difficulty of observing this value in practice. The availability of selective herbicides for efficient weed control is found to determine whether or not it is profitable to adopt lucerne pasture under optimal... |
| Tipo: Article |
Palavras-chave: Annual ryegrass; Herbicide resistance; Multiple-phase optimal control; Crop Production/Industries. |
| Ano: 2008 |
URL: http://purl.umn.edu/118547 |
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| Doole, Graeme J.; Pannell, David J.. |
| Use of lucerne (Medicago sativa L.) pastures in crop rotations has been proposed as a method to enhance weed management options for growers facing herbicide resistance in Western Australia. An existing model for analysing herbicide resistance in the important crop weed annual ryegrass (Lolium rigidum Gaud.) is consequently extended to include lucerne, used for grazing by a sheep enterprise. Seven rotational options are analysed, including various combinations of lucerne, annual pastures, and crops. Lucerne provides additional weed management benefits across the rotation, but in the region studied these benefits are only sufficient to make lucerne rotations the most profitable option in situations where ryegrass is resistant to multiple herbicide groups,... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Crop Production/Industries. |
| Ano: 2007 |
URL: http://purl.umn.edu/9233 |
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| Doole, Graeme J.; Pannell, David J.. |
| Environmental policy evaluation is characterised by a paucity of information. Bounded sets may be more appropriate for representing this ambiguity than traditional probability distributions. A formal calibration method for regional policy models, positive mathematical programming, is thus extended to incorporate parameter definition using bounded sets through the novel method of robust non-linear programming. The resulting procedure identifies strong bounds on the range of abatement costs accruing to environmental policy and improves the relevance and value of modelling studies through not limiting conclusions to realisations of specific point estimates or probability distributions. Moreover, it may easily be solved using standard mathematical-programming... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Interval analysis; Nonpoint pollution; Robust optimisation.. |
| Ano: 2009 |
URL: http://purl.umn.edu/48036 |
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| Doole, Graeme J.; Hertzler, Greg. |
| The capacity of global agricultural production to meet increased demand for food from population growth and wealth accumulation is threatened by extensive land degradation. Nonetheless, previous research has focused primarily on the dynamic implications of input management and ignored land-use choice. This paper extends this theory through an examination of the intertemporal management of agricultural land through the use of non-crop inputs, such as fertilizer, and land uses that either degrade or restore productivity. The need to consider the relative total asset value of alternative crops over time is demonstrated. Moreover, higher output prices for degrading crops are shown to increase their relative value, motivating the later adoption of substitutes.... |
| Tipo: Journal Article |
Palavras-chave: Crop sequences; Land degradation; Regime switching; International Development; Production Economics; Q15; Q24. |
| Ano: 2011 |
URL: http://purl.umn.edu/100643 |
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| Registros recuperados: 15 | |
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