Corn Hybrid Response to In‐Furrow Starter Fertilizer as Affected by Planting Date

Abstract

Use of in‐furrow starter fertilizer (IFSF) is common in the Upper Midwest to enhance early‐season corn (Zea mays L.) growth because of cold soils in the early spring which limit P uptake by corn. The objective of this study was to evaluate the agronomic and economic responses of corn to IFSF and how this was affected by planting date (PD) for hybrids of contrasting relative maturity (RM). A 3‐yr experiment was conducted in 2010 to 2012 at two locations in southern Minnesota which evaluated IFSF at 0 and 65 kg ha−1 of 100–150–0 (g kg−1 N–P–K) with three corn hybrids (94‐, 99‐, and 104‐d RM) planted on three dates spaced on 10‐ to 16‐d intervals. Delaying PD resulted in greater corn plant density, grain moisture at harvest, and kernel m−2, and decreased early‐season plant height, days to silking, kernel mass, and corn grain yield. Planting a later‐RM hybrid resulted in greater early‐season plant height, days to silking, grain moisture at harvest, kernel mass, and biomass and grain yield. In‐furrow starter fertilizer increased early‐season plant height and kernel mass and decreased days to silking, grain moisture at harvest, and kernel m−2. Economic net return to grain production was not affected by IFSF. Results from this study confirm that planting mid‐ to late‐RM hybrids during late April to mid‐May produces greatest net return in the Upper Midwest, and that the response of grain yield to IFSF is not affected by PD for hybrids of differing RM.Core Ideas A P‐based starter fertilizer applied in‐furrow increased early corn growth and decreased grain moisture at harvest, but did not increase grain yield on soils testing medium to high in P. Corn hybrids later in relative maturity and earlier planting increased economic net return. Net return per hectare was not increased when in‐furrow starter fertilizer was utilized on medium to high P‐testing soils. A small reduction in grain moisture at harvest can reduce grain drying expenses to offset the cost of in‐furrow starter fertilizer. The likelihood of a profitable economic net return to in‐furrow starter fertilizer is not affected by corn planting date or hybrid relative maturity.