Phosphate Fertilizer Reactions under Various Soil Conditions

Agronomy (Soils

NITROGEN CARRY-OVER IMPACTS IN IRRIGATED COTTON PRODUCTION, SOUTHERN HIGH PLAINS OF TEXAS

A dynamic optimization model which introduces an intertemporal nitrate-nitrogen residual function is used to derive and evaluate nitrogen fertilizer optimal decision rules for irrigated cotton production in the Southern High Plains of Texas. Results indicate that optimal nitrogen applications critically depend on initial nitrate-nitrogen levels and nitrogen-to-cotton price ratios. Also, the results indicate that single-year optimization leads to suboptimal nitrogen applications, which helps explain long-term cotton yield declines in the Southern High Plains of Texas; but single-year optimization does not significantly impact the net present value of returns of irrigated cotton operations.Crop Production/Industries,

INCORPORATION OF SOIL TEST RESULTS IN THE DEVELOPMENT OF OPTIMAL LONG-TERM FERTILIZER POLICIES FOR FARMERS

The economics of using soil test results for making fertilizer recommendations in the presence of nutrient carry-over are discussed. A model for maximizing long run returns with nutrient carry-over is presented. Dynamic programming is used to determine fertilizer applications for grain sorghum given an initial soil test value

NITROGEN CARRY-OVER IMPACTS IN IRRIGATED COTTON PRODUCTION, SOUTHERN HIGH PLAINS OF TEXAS

A dynamic optimization model which introduces an intertemporal nitrate-nitrogen residual function is used to derive and evaluate nitrogen fertilizer optimal decision rules for irrigated cotton production in the Southern High Plains of Texas. Results indicate that optimal nitrogen applications critically depend on initial nitrate-nitrogen levels and nitrogen-to-cotton price ratios. Also, the results indicate that single-year optimization leads to suboptimal nitrogen applications, which helps explain long-term cotton yield declines in the Southern High Plains of Texas; but single-year optimization does not significantly impact the net present value of returns of irrigated cotton operations

Effects of irrigation methods on groundwater pollution by nitrates and other solutes /

Prepared by Texas Agricultural Experiment Station, Lubbock, Texas, under grant no. S-802806 (Formerly 13030EZM)Includes bibliographical references (pages 327-328).Mode of access: Internet