Using the Kernel Milk Line to Determine When to Harvest Corn for Silage

The position of the kernel milk line can be used to visually monitor grain maturation in corn (Zea mays L.). The objective of this study was to determine if the kernel milk line could be used to determine when to harvest corn for silage. Four hybrids (two full season, and two short season) were grown in the field during each of three years. As plants approached maturity, ears were removed and the position of the kernel milk line was noted. Ears and stover were then chopped together and moisture content of the fodder was determined. Measurements were taken at: full‐dent (every kernel on the ear dented), ½‐milk (milk line positioned half way between the tip and base of the kernel), ¼‐milk (milk line positioned ¾ of the way from tip to base), and no‐milk (milk no longer present in the kernel). The kernel milk line was determined to be a reliable indicator of fodder moisture status. Fodder moisture values at the four selected stages were: full‐dent, 74%; ½‐milk, 69%; ¼‐milk, 65%; and no‐milk, 61%. The ideal fodder moisture for corn silage stored in upright, unsealed silos is considered to be 65%. This fodder moisture occurred very near the ¼‐milk stage. The recommended range in fodder moisture for silage harvest is usually between 68 and 61%. This range was found to be coincident with the interval between the ½‐milk and no‐milk stages. Under the conditions of the present study, this interval lasted an average of 13 d.