Gathering preseason data is vital in gaining the most from all three yield components, says Ken Ferrie, Farm Journal field agronomist. At Corn College 2015, Ferrie outlined the necessity of proper zone management throughout the season and warned growers not to surrender gains due to poor field decisions. Preseason homework is based on past calibrated yield maps, soil tests taken by texture, topography maps, and soil nutrient data.
In-season decisions must be based on a boots-on-the-ground approach. “The best laid variable rate plan has to be backed with someone going into the field. Everything must be ground-truthed,” Ferrie says. Nitrate collection, tissue testing and hybrid inspection should be coupled with a bird’s-eye view of the field to locate problem zones – thermal, NDVI or even high resolution pictures.
In light soils with low water-holding capacity, Ferrie says lower populations manage water; flex-eared hybrids can make up for lower ear counts; and a pendulum leaf structure helps catch sunlight. In racehorse soils with good fertility, an upright leaf structure maximizes sunlight and Ferrie recommends a population push to boost ear count. On acreage with a great deal of soil variability, a multi-hybrid approach is a good fit.
According to Ferrie, hybrid selection initially should be based on yield potential, and choosing a low-yielding hybrid due to leaf structure doesn’t translate to high yields. “There’s been a tendency to treat all hybrids alike. Some hybrids will respond to higher populations, but some simply will not, and when they come apart, it can be 15 to 30 bu. per acre because they’re pushed too hard.”