Kernel moisture content at physiological maturity averages 30 percent, but can vary from 25 to 40 percent grain moisture. While not strictly a stage of grain development, harvest maturity is often defined as that grain moisture content where harvest can occur with minimal kernel damage and mechanical harvest loss. Harvest maturity is usually considered to be near 25 percent grain moisture. And Yield Bob Byrnes, Extension Educator, Minnesota Inadequate moisture during any period of growth can result in reduced grain yield. Nutrient availability, uptake, and transport are impaired without sufficient water.
Plants weakened by stress are also more susceptible to disease and insect damage.
During the growing season the most visible evidence of drought stress is plant wilting. Four days of visible wilting can reduce potential corn yield by 5 to 10 percent during vegetative growth, and by 40 to 50 percent during silking and pollination. Drought stress in corn in the vegetative stage, which is prior to tassel and silk emergence, may result in small ear size. Moisture stress may reduce both ear length and the number of potential kernels on each ear. If ear size is reduced during this period, it cannot be corrected by relieving the moisture stress later in the season.