An assessment of soil nitrogen testing considering the carry-over effect

In order to evaluate the economic and environmental consequences of soil nitrogen tests, this paper combines a dynamic fertilizer use decision model with a crop production model. The pre-side-dress soil N-test is evaluated for a hypothetical farmer growing corn at the ARS Sustainable Agriculture Demonstration Farm site in southern Maryland. For a farmer not currently using a soil N-test, adoption of this technology can lead to the enhancement of net farm income and the reduction in nitrogen loss to the environment. This will transpire only if the farmer is currently underestimating nitrogen carry-over by more than 25% or applying nitrogen fertilizer based solely on an expected plateau-yield goal. (C) 2001 Elsevier Science Inc. All rights reserved.