No-Tillage Corn Hybrids Response to Starter Fertilizer

Abstract

Starter fertilizer can help improve early-season corn (Zea mays L.) growth, especially under cool soil conditions, but corn hybrids may differ in their response to starter fertilizer. This study evaluated the response of corn hybrids to complete starter fertilizers applied under no-tillage, dryland conditions. Nine site-years of data were collected from 1993 through 1995 at four geographical locations: Doon (NW1) in extreme NW Iowa, Sutherland (NW2) in central NW Iowa, Lewis (SW), and Crawfordsville (SE). The soil types were as follows: NW1-Moody silty clay loam (fine-silty, mixed, superactive, mesic Udic Haplustolls); SW-Marshall silty clay loam (fine-silty, mixed, superactive, mesic Typic Hapludolls); SE-Nira silty clay loam (fine-silty, mixed, superactive, mesic Oxyaquic Hapludolls); and NW2-Primghar silty clay loam (fine-silty, mixed, superactive, mesic Aquic Hapludolls). Each hybrid was planted with and without starter fertilizer applied 2 in, to the side and 2 in, below the seed at planting. Hybrid-by-starter interactions were not significant for early-season dry matter production, nutrient concentration, or grain yield in any of the site-years, indicating that the hybrids, on average, responded similarly to starter fertilizer. Starter fertilizer increased early-season growth significantly in four of eight site-years and grain yield in seven of nine site-years. Average grain yield increases ranged from 4 bu/acre at the NW2 site in 1993 to 18 bu/acre at the SE site in 1995. Yield increases were not significant either year at the NW1 site. Increases in dry matter yield ranged from 18.7% at the SW site to 97.8% at the SE site in 1994. Starter fertilizer affected tissue K concentration to a much larger degree than it did N and P concentrations especially at the SE site. The results suggest that starter fertilizer will likely benefit no-tillage corn for most hybrids in the northern corn belt even on soils with adequate P and K.