Submitted to: International Nitrogen Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 20, 2001
Publication Date: N/A
Technical Abstract: The ability to accurately predict soil nitrogen available for crop production has been an elusive goal of nitrogen management for the past half century. Efforts to develop laboratory soil tests to predict nitrogen with mineralization potential as an indicator of available nitrogen for crop growth have largely failed. While the pre-sidedress nitrate test (PSNT) has shown some promise, logistical difficulties exist that hinder its implementation by farmers. The importance of landscape-level parameters as drivers of nitrogen availability may explain why random point-sample methods fail. An assessment of how landscape influences the spatial distribution of processes governing the nitrogen cycle was conducted at the Beltsville Agricultural Research Center, Beltsville, Maryland. Physical, chemical, and biological parameters as well as surface and subsurface topographic features were evaluated in assessing nitrogen behavior on a watershed scale. The spatial structure of various nitrogen cycling processes was found to be closely linked to surface features such as topographical curvature and subsurface structures. These findings suggest that landscape parameters will be a critical driving force in developing nitrogen management models. Such models when used with remotely sensed data for crop nitrogen status could facilitate site specific management of nitrogen for crop production, thus leading to reduced nitrogen loss from agricultural ecosystems.