VARIATION IN MARGINAL RESPONSE TO NITROGEN FERTILIZER BETWEEN LOCATIONS

A logistic growth equation with time and location varying parameters was used to model corn response to applied nitrogen. A nonlinear dummy-variable regression model provided a parsimonious representation of site and time effects on parameter values. The model was used to test for the equality of the mean marginal product of nitrogen fertilizer between locations on the coastal plain of North Carolina. Monte Carlo simulation and bootstrap simulation were used to construct finite sample covariance estimates. Results support rejection of the hypothesis that mean marginal products are equal when nitrogen is applied at 168 kg/ac. A comparison of bootstrapped errors and asymptotic errors suggests that results based on asymptotic theory are fairly reliable in this case.bootstrap, corn yield, marginal product, nitrogen fertilizer, nonlinear regression, Crop Production/Industries, C200, C150, Q100,

TREATMENT OF INCOMPLETE AND MISSING COVARIATE INFORMATION IN A BAYESIAN GENERALIZED LINEAR MODEL OF MARINE RECREATIONAL ANGLER'S CHOICE OF FISHING SITE

Economic surveys often report income via a categorical variable, and income and wage information is often missing altogether for a large fraction of the sample. The Bayesian inferential framework allows one to specify and estimate models for incomplete and missing covariate information. Here multiple choice models of recreational anglers' choice of fishing site are estimated and alternative specifications for incomplete and missing income and wage data are compared

VARIATION IN MARGINAL RESPONSE TO NITROGEN FERTILIZER BETWEEN LOCATIONS

A logistic growth equation with time and location varying parameters was used to model corn response to applied nitrogen. A nonlinear dummy-variable regression model provided a parsimonious representation of site and time effects on parameter values. The model was used to test for the equality of the mean marginal product of nitrogen fertilizer between locations on the coastal plain of North Carolina. Monte Carlo simulation and bootstrap simulation were used to construct finite sample covariance estimates. Results support rejection of the hypothesis that mean marginal products are equal when nitrogen is applied at 168 kg/ac. A comparison of bootstrapped errors and asymptotic errors suggests that results based on asymptotic theory are fairly reliable in this case