Nitrogen Movement with Furrow Irrigation Method and Fertilizer Band Placement

Abstract Alternate‐furrow irrigation has been proposed as a method to increase irrigation water use efficiency, increase capture and storage of rainfall during the irrigation season, and decrease deep percolation of water. We hypothesized that less fertilizer leaching would occur if the applied fertilizer were spatially separated from the irrigation water in a furrow irrigation system. A study was conducted on a Fort Collins loam (fine‐loamy, mixed, superactive, mesic Aridic Haplustalf) in 1994 and 1995 near Fort Collins, CO. Nitrogen uptake by corn ( Zea mays L.) and N leaching were determined with alternate‐furrow and every‐furrow irrigation water applications, each with fertilizer bands of 15 N‐enriched (NH 4 ) 2 SO 4 placed either in the row or in the furrow. In 1994 fertilizer N leached to ≈1 m for the every‐furrow irrigation with fertilizer placed in the irrigated furrow, but to 0.5 m or less for the other treatments. In 1995 the fertilizer leaching was similar among the treatments because of less irrigation and more rainfall during the growing season. There were no statistically significant differences for irrigation water placement effects on plant biomass or total N uptake, indicating that alternate‐furrow irrigation is not detrimental to crop production compared with every‐furrow irrigation for similar applications of water. This study showed that placing fertilizer in the nonirrigated furrow of an alternate‐furrow irrigation system or placing fertilizer in the row with either alternate‐ or every‐furrow irrigation has the potential to decrease fertilizer leaching without reducing crop productivity.