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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #104947
Title: USING SITE-SPECIFIC NITROGEN APPLICATIONS TO IMPROVE WATER QUALITY

Author
item DAVIS, GLENN - UNIV OF MO
item SHANNON, KENT - UNIV OF MO
item Kitchen, Newell
item Sudduth, Kenneth - Ken
item Drummond, Scott

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/7/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Site-specific application of nitrogen (N) fertilizer is a promising tool for reducing N leaching losses from farm fields without yield reductions. The objective of this research was to develop strategies for variable N applications on loess, Mississippi delta, and claypan soils in Missouri. Constant-rate strips (300 to 600 m long) at different rates of ammonium nitrate (0 to 224 kg N/ha) were applied to corn (Zea mays L.). Indirect evaluations of the spatial effects of N applications on water quality included chlorophyll meter measurements and yield response functions derived from grain harvest data. Direct measurements included root-zone nitrate sampled by buried (90-cm depth) suction lysimeters and residual nitrate in soils after crop removal. Both N application rate and site factors such as landscape position and soil properties were important determiners of N loss. These site factors interacted with climate to influence losses and N uptake.