|Baker, J - IOWA STATE UNIVERSITY|
|Ressler, D - IOWA STATE UNIVERSITY|
|Horton, R - IOWA STATE UNVIERSITY|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 12, 1999
Publication Date: N/A
Technical Abstract: Fertilizer nitrogen that moves with water to subsurface drain tubes is no longer available for crop growth and is often transported to surface waters, where it is considered a contaminant. Localized soil compaction and doming (LCD) above a nitrogen fertilizer band to divert percolating water around the zone of fertilizer injection may be one way to reduce nitrate leaching from agricultural fields. Results are presented from two field studies and one lysimeter study that compare the movement and corn uptake of fertilizer nitrate and tracers applied with an LCD applicator and conventional knife applicators. The results indicated that localized compaction and doming over a band of nitrogen fertilizer can reduce nitrate leaching and improve nitrogen use efficiency in a rainfed corn field, especially during years that have greater than average rainfall after N fertilization. In years, when rainfall after fertilization was normal or less than normal, fertilizer nitrate did not move significantly deeper into the soil and corn uptake and yield were similar with the two application methods. Because nitrogen fertilizers were applied after planting in our studies, we speculate that localized compaction and doming may have a greater effect on nitrate movement if fertilizer were applied in early spring or in the previous fall. This topic needs further study. Additionally, further study is needed to determine if there are efficiency advantages to combining an LCD applicator with mechanical cultivation for weed control.