Submitted to: Water Quality Beyond 2000
Publication Type: Proceedings
Publication Acceptance Date: November 4, 1998
Publication Date: N/A
Technical Abstract: Furrow irrigation often leaches NO3-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 and yield yet decrease nitrate leaching. In a two-year field study on Portneuf silt loam (Durinodic Xeric Haplocalcid), we evaluated the effects on corn silage yield and N uptake 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. Interactions involving irrigated-furrow positioning affected silage yield only in Year Two. In Year One, where water was applied to the same furrow, yield from banded and broadcast plots was similar, about 20.3 Mg/ha, when averaged across row spacings. In Year Two, in contrast, yield from banded plots was 26% greater than from broadcast plots in 0.56-m rows and 7% greater in 0.76-m rows. Positioning irrigation water apart from banded urea either maintains N uptake and yield or increases them by up to 26%.