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| Pautsch, Gregory R.; Babcock, Bruce A.; Breidt, F. Jay. |
| Studies examining the value of switching to a variable rate technology (VRT) fertilizer program assume producers possess perfect soil nitrate information. In reality, producers estimate soil nitrate levels with soil sampling. The value of switching to a VRT program depends on the quality of the estimates and on how the estimates are used. Larger samples sizes, increased spatial correlation, and decreased variability improve the estimates and increase returns. Fertilizing strictly to the estimated field map fails to account for estimation risk. Returns increase if the soil sample information is used in a Bayesian fashion to update the soil nitrate beliefs in nonsampled sites. |
| Tipo: Journal Article |
Palavras-chave: Crop Production/Industries. |
| Ano: 1999 |
URL: http://purl.umn.edu/30797 |
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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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| 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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