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| Registros recuperados: 13 | |
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| Carriquiry, Alicia L.; Breidt, F. Jay; Lakshminarayan, P.G.. |
| Evaluating the environmental and economic impacts of agricultural policies is not a simple task. A systematic approach to policy analysis would include investigating the effect of factors such as tillage practices, crop rotations, type and amount of chemical used, weather, topography, and other soil attributes, on observables such as amount of soil eroded or chemical leached into the groundwater. For comparison purposes, the effects of those factors on the response variable would have to be assessed under alternative policy scenarios. Because the number of factor levels is alarmingly high in most problems, and because policies to be evaluated are often not in place at the time of the study, practitioners have resorted to simulation experiments to... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Computer experiment; Sampling; Policy analysis; Agricultural and Food Policy. |
| Ano: 1996 |
URL: http://purl.umn.edu/18350 |
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| Carriquiry, Alicia L.; Fuller, Wayne A.; Goyeneche, J.J.; Dodd, Kevin W.. |
| In recent years, it has become apparent that ratios of usual intakes of dietary components, such as the percent of calories from fat or the percent of calories from standard fat, are important indicators of dietary adequacy. The problem of estimating a percentile of the distribution of ratios of usual intakes of nutrients presents problems that arise from the fact that, from a statistical point of view, ratios of dietary components can be viewed as ratios of random variables. The methods developed by Nusser et al. (1995) to estimate usual intake distributions of nutrient, for example, cannot be directly applied to ratios, since the ratio of usual intakes is not equal to the mean of the ratio of daily intakes. In this paper we discuss the problem of... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Food Consumption/Nutrition/Food Safety. |
| Ano: 1995 |
URL: http://purl.umn.edu/18673 |
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| Bouzaher, Aziz; Shogren, Jason F.; Holtkamp, Derald; Gassman, Philip W.; Archer, David W.; Lakshminarayan, P.G.; Carriquiry, Alicia L.; Reese, Randall; Furtan, William Hartley; Izaurralde, R. Cesar; Kiniry, James R.. |
| The interface between RS-CRAM and the environmental component of the integrated modeling system is described for crops, crop sequences, and management systems representative of western Canada. An experimentally designed set of EPIC simulations were performed to generate erosion output that was used to construct wind and water erosion metamodels (response functions). The results of the EPIC simulations indicate that wind and water erosion would be the dominant erosion problem over most of Saskatchewan and Manitoba. For Alberta, water erosion was predicted to be the dominant problem, except for the southern portion of the province. Erosion impacts were sensitive to tillage and cropping patterns. EPIC-predicted yields did not vary much across tillage, a... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Agricultural and Food Policy; Environmental Economics and Policy. |
| Ano: 1995 |
URL: http://purl.umn.edu/18681 |
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| Carriquiry, Alicia L.; Fuller, Wayne A.; Goyeneche, J.J.; Jensen, Helen H.. |
| Data obtained from dietary intake surveys are often used to estimate the proportion of the population with insufficient (or excessive) intake of certain dietary components. It is generally agreed that the usual or long-run average intake of a nutrient is the appropriate measure of an individual's intake. In this light, assessments of the dietary status of the population should be based on the distribution of usual intakes for each dietary component. Several methods have been proposed for estimating the distributions of usual intakes from dietary data. The methodology presented by Nusser et al. (1995) is very appealing, since it accounts for all of the attributes of dietary intake data, and explicitly recognizes that when data are collected on... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Food Consumption/Nutrition/Food Safety. |
| Ano: 1995 |
URL: http://purl.umn.edu/18658 |
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| Babcock, Bruce A.; Carriquiry, Alicia L.; Stern, Hal S.. |
| The value of soil-test information in planning fertilizer application levels is determined by using agricultural field-plot data to estimate the posterior distribution of mean soil-nitrate concentrations at a give location. Optimal decisions concerning fertilizer application levels are made with respect to this posterior distribution. Average reductions in fertilizer application rates range from 15 to 41 percent, depending on the form of prior information that is available. These reductions are achieved by increasing the variability of application rates over time. Disregarding the uncertainty that remains after the soil testing significantly overstates the expected benefits of soil testing. |
| Tipo: Working or Discussion Paper |
Palavras-chave: Bayesian methods; Fertilizer rates; Posterior distributions; Soil tests; Farm Management. |
| Ano: 1996 |
URL: http://purl.umn.edu/18633 |
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| Carriquiry, Alicia L.; Breidt, F. Jay; Lakshminarayan, P.G.. |
| Evaluating the environmental and economic impacts of agricultural policies is not a simple task. A systematic approach to evaluation would include the effect of policy-dependent factors (sue as tillage practices, crop rotations, and chemical use) as well as the effect of policy-independent covariates (such as weather, topography, and soil attributes) on response variables (such as amount of soil eroded or chemical leached into the groundwater). For comparison purposes, the effects of these input combinations on the response variable would have to be assessed under competing policy scenarios. Because the number of input combinations is high in most problems, and because policies to be evaluated are often not in use at the time of the study, practitioners... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Research Methods/ Statistical Methods. |
| Ano: 1997 |
URL: http://purl.umn.edu/18460 |
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| Bouzaher, Aziz; Shogren, Jason F.; Holtkamp, Derald; Gassman, Philip W.; Archer, David W.; Lakshminarayan, P.G.; Carriquiry, Alicia L.; Reese, Randall; Kakani, Dharmaraju; Furtan, William Hartley; Izaurralde, R. Cesar; Kiniry, James R.. |
| This report describes an integrated agro-ecological modeling system that was developed to assess the potential economic and soil erosion impacts of different agricultural policies for the Canadian prairie provinces of Alberta, Saskatchewan, and Manitoba. The system was constructed by linking erosion metamodels (response functions), based on multiple simulations of the USDA Erosion Productivity Impact Calculator (EPIIC), with a modified version of Agriculture Canada's Canadian Regional Agriculture Model (CRAM) denoted as RS-CRAM (resource sensitive CRAM). A summary of both the environmental and agricultural decision (RS-CRAM) components are presented, including a description of the modifications and enhancements that were made to CRAM. Results of policy... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Agricultural and Food Policy; Environmental Economics and Policy. |
| Ano: 1996 |
URL: http://purl.umn.edu/18660 |
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| Bouzaher, Aziz; Shogren, Jason F.; Holtkamp, Derald; Gassman, Philip W.; Archer, David W.; Lakshminarayan, P.G.; Carriquiry, Alicia L.; Reese, Randall; Kakani, Dharmaraju; Furtan, William Hartley; Izaurralde, R. Cesar; Kiniry, James R.. |
| Tipo: Working or Discussion Paper |
Palavras-chave: Agricultural and Food Policy; Environmental Economics and Policy. |
| Ano: 1996 |
URL: http://purl.umn.edu/18674 |
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| Registros recuperados: 13 | |
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