Corn Hybrids with Contrasting Root Systems: Response to Soil and Fertilizer Phosphorus.

With current corn genetic improvements for water-limited scenarios, root system architecture and growth may affect overall nutrient uptake particularly for immobile nutrients.  The objective of this study was to evaluate plant response and phosphorus uptake with contrasting, generally shallow and generally deep rooted corn hybrids. A total of seven sites were established over two years, two sites in 2011 and five sites in 2012. All sites are under rain fed conditions except for two sites that were added in 2012 under irrigation. Two hybrids were assessed with treatments of starter and broadcast P application methods. The experiment design was a factorial and in a randomized complete block, with two starter, two broadcast and two hybrid combinations for a total of 8 treatments combinations. Early growth biomass was evaluated at the V6 growth stage, including whole plant tissue P concentrations. Ear leaf tissue were also collected at the VT-R1 growth stage and analyzed for P concentration.  Tissue samples were also analyzed for nitrogen and potassium. Finally grain yield is assed at the end of each growing season.