CORN GROWTH AND NITROGEN UPTAKE WITH FURROW IRRIGATION AND FERTILIZERBANDS

Furrow irrigation is commonly used to provide supplemental water to ro w crops, Alternate-furrow irrigation has been proposed as a method to decrease deep percolation water losses as well as the Leaching of fert ilizer and pesticides, A study was conducted on a Ulm clay loam (fine, smectitic, mesic Ustic Haplargids) in 1994 and 1995 near Fort Collins , CO. Corn (Zea mays L.) growth and N uptake were measured under alter nate-furrow and every-furrow irrigation water applications, each with fertilizer bands placed either in the row or in the furrow, Nitrogen-l s'-deplete (NH4)(2)SO4 fertilizer was used to distinguish plant uptake of fertilizer N from uptake of naturally occurring N. There were no d ifferences in plant response to alternate-furrow or every-furrow irrig ation water placement for the same amount of water applied, Greater fe rtilizer-N uptake occurred with row placement than with furrow placeme nt of N fertilizer. Early in the growing season, fertilizer-N uptake f rom row placement was from 2 to 10 times the fertilizer-N uptake from furrow placement, By the end of the growing season, the average total- N uptake from row placement was 12% greater than for furrow placement, Placing the fertilizer in the nonirrigated furrow of the alternate-fu rrow irrigation treatment decreased N availability by 20% compared wit h the average of the other treatments, If alternate-furrow irrigation is used tu increase water use efficiency in furrow-irrigated fields, p lacing the N fertilizer in the nonirrigated furrow of the alternate-fu rrow irrigation system could decrease N availability because of drier soil conditions in the nonirrigated furrow, Row placement of N fertili zer seems to be beneficial in both alternate-furrow and every-furrow i rrigation applications.