Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 29, 1995
Publication Date: N/A
Technical Abstract: A systems approach considering both N fertilizer placement and irrigation water management may decrease nitrate movement to groundwater. The objectives of a two-year field study were to evaluate 1) urea placement (broadcast or banded), 2) row spacing, and 3) alternate-furrow irrigation management effects on soil nitrate concentrations under field corn (Zea mays L.) grown on a Portneuf silt loam (Durixerollic Calciorthid). Soil samples were taken (to 1 m or more) under the row about six days after each irrigation in 1988 and 1989. In 1988, when water was applied alternately on each side of the row with consecutive irrigations, nitrate moved laterally, concentrating under the row. Under 0.76-m rows, there was more nitrate at 0.6-0.9 m in broadcast plots (10.4 mg/kg) than in banded plots (8.6 mg/kg), suggesting more nitrate leached from the broadcast plots. Nitrate concentrations at 0.6-0.9 m were 31% lower in plots irrigated only on the non-fertilized side of the row, compared with alternating irrigations on both sides of the row. Banding and sidedressing urea near a dry furrow and irrigating only the opposite furrow reduced soil nitrate below 0.6 m.