Dissecting Planting Date, Hybrid Maturity, and Weather Effects on Maize Yield.

Optimum planting date to achieve high yields in the central U.S. Corn Belt falls within the time frame of mid-April through early-May for corn (Zea mays). It is common for planting to be delayed past the optimum timeframe due to the soil being too wet or cold. As planting is delayed growers must decide to continue to use a well-adapted, long season hybrid maturity or switch to a shorter season hybrid maturity. The objective of this study was to find the optimum combination of planting date by hybrid maturity for maximizing corn yield per geological location. Groups of different hybrid maturities were planted at four times throughout the growing season, ranging from mid April to late June. Delays in planting date reduced grain yield significantly across maturities. With yield being the highest within the optimum planting timeframe and decreasing the more planting date was delayed.. Similarly as planting was delayed the silking date was also delayed, shortening the length of grain fill. Earlier planting dates were allowed to accumulate more radiation and heat units throughout the growing season. The effect of relative hybrid maturity had little effect on yield across all planting dates.