Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 14, 2002
Publication Date: November 14, 2002
Citation: KASPAR, T.C., COLVIN, T.S., JAYNES, D.B., KARLEN, D.L. CORN RESPONSE TO NITROGEN ACROSS LANDSCAPE POSITIONS. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2002. CD-ROM. MADISON, WI. Technical Abstract: Variable rate nitrogen application within agricultural fields will require the identification of field areas that are more or less responsive to applied N fertilizers. In this study, we examined the grain yield response of corn to N fertilizers applied at either 34 kg N ha**-1 or 258 kg N ha**-1 along a transect that was oriented parallel to a hillslope. In addition to yield, plant height, stalk nitrate concentration, grain protein, and 100 kernal weight were measured along the transect. Yield responses to nitrogen fertilizer were greatest at the summit and shoulder position of the hillslope, moderate along the backslope and upper footslope, and least at the lower footslope and toeslope positions. There were also three small areas along the transect where yields did not differ much between the two N rates. All three of these areas showed signs of past erosion or rills and probably represent areas where other factors are more limiting to yields than N. Early season plant height was useful for identifying these localized areas, but did not identify major hillslope trends in N responsiveness.