Submitted to: Journal of Soil and Water Conservation
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 1999
Publication Date: N/A
Technical Abstract: Furrow irrigation often leaches nitrate-N toward ground water. Banding and sidedressing N fertilizer on a non-irrigated side of a row of corn (Zea mays L.) might maintain or increase N uptake in silage and decrease nitrate-N in soil profiles at harvest. In a two-year field study on Portneuf silt loam (Durinodic Xeric Haplocalcid), we evaluated the effects on N uptake in corn silage and profile nitrate-N of 1) urea placement (broadcast pre-plant vs. banded at planting), 2) row spacings (0.76-m vs. a modified 0.56-m with every pair of rows near the irrigated furrow), and 3) irrigated-furrow positioning (applying water to the same or opposite side of the row with successive irrigations). Where water was applied to one side of the row, then the other, two-year average N uptake from 0.76-m rows was 131 kg/ha, 15% greater (P<0.001) than from 0.56-m rows. Where water was applied to the same (i.e., non-fertilized) furrow, N uptake from banded plots was equal to that from broadcast plots in the first year but was 21% greater the second. Preliminary soil analyses indicate that profile totals of nitrate-N (to a depth of 0.9 m under 0.76-m rows) were less where water was applied to the same (non-fertilized) furrow throughout the growing season rather than to the furrow on the opposite side of the row with successive irrigations. Positioning irrigation water apart from banded urea either maintains or increases N uptake and minimizes nitrate-N in 0.9-m soil profiles.