Fertility, Hybrid Selection, and Input Strategies to Optimize Yield and Early Harvest in the Mid-South.

Heat and drought limit corn productivity in MS; the 2013 and 1014 growing seasons were wet and cool years and the exceptional corn yields reminded us that corn grows well in these conditions.  One way to avoid the negative consequences of summer heat and drought this is to plant earlier so that a plant’s environment during critical growth stages is cooler and water is less likely to be limiting.  Planting earlier may expose seedling corn to less than optimal growing conditions.  We conducted a series of experiments to measure the effect of various treatments on early corn emergence, growth and vigor.  In 2015 we were limited by wet fields and physically unable to plant until early May and the resulting benefits of starter fertilizer, zinc, and hormones were minimal. Our seedlings emerged fully within 4 days after planting. Soil temperature was well above 60 degrees by the time we planted so all treatments grew vigorously essentially negating any potential treatment effects.  There were no obvious treatment effects in responses to fertilizer or hormone application so data were pooled by hybrid and by location.  This was likely because we planted late and the plants grew rapidly as soon as they emerged; moisture and heat units were non-limiting.  The short season hybrid performed well at MSU but the full season hybrid was 18 bu better at Verona. The short season hybrid was 5% drier at harvest than the full season at MSU and they were about the same at Verona. This suggests that planted late, under hot conditions the short season might provide a 1 week earlier harvest, but this might be larger if our planting date were as scheduled two months earlier at the beginning of March.