Evaluation of Yield, Quality, and Plant Composition of Early-Maturing Corn Hybrids Harvested at Three Stages of Maturity

Abstract

The decision on when to harvest whole-plant corn (Zea mays L.) for silage in the Pacific Northwest has been based on yield, DM content, kernel milk line, and ability to harvest prior to a rainy season. However, no local data have been available to guide producers in this decision process. This study was conducted to evaluate the effect of maturity rating of hybrids and maturity at harvest on yield, plant physical and chemical composition, and digestibility. Whole-plant corn was harvested at milk, one-half milk line, and black layer (physiological maturity). Data collected over 2yr from hybrids grown indicated that as maturity progressed from milk to black layer: whole-plant DM content increased from 20 to 45%; grain content increased from 11 to 50%; contents of crude protein, NDF, ADF, lignin, and water-soluble carbohydrates decreased, and in vitro DM digestibility (IVDMD) increased. Results suggest that ensiling whole-plant corn in this region should commence at the one-half milk line stage of maturity. Harvest should occur prior to physiological maturity due to the risk of field losses and the potential for increased storage losses when whole plant is stored above 45% DM in bunker silos.