Corn Silage Dry-Down: Week of August 25, 2025

Corn silage moisture content continues to be critical to harvesting a high-quality and high-yielding forage crop. Extension Educators across Pennsylvania are working with cooperating farms to harvest, chop, dry, and track the moisture content of corn silage fields around the state.

Accumulated Growing Degree Days (GDD): A measure of the accumulated growing degree days counted at this location since planting. Calculated using 86/50-degree cutoffs.

Precipitation Deviation: A measure of this location's departure from the 10-year precipitation average, calculated by subtracting rainfall from planting to the current date from the 10-year average.

Growing Degree Day (GDD) Deviation: A measure of this location's departure from the 10-year GDD average, calculated by subtracting GDD accumulation from planting to the current date from the 10-year average.

*Lancaster/Lebanon locations were not sampled as of this posting; data represents the most recent tests.

Be sure to monitor field conditions and test moisture levels to determine the current moisture level of your corn crop. The average daily dry-down rate for silage is about 0.5% of moisture loss per day, with rates ranging from 0.0 to 1.0% in extreme weather conditions. In our observations, daily dry-down rates have averaged about 0.5%. 

Currently, locations across southeastern Pennsylvania are trending slightly cooler and significantly wetter than the 10-year average for these locations. Pollination in earlier plantings has been successful, and disease pressure varies among locations. Torrential rains in July, followed by limited precipitation in August, have many fields in varying levels of moisture stress. All locations except for the early planting at Lancaster are currently wetter than desired for corn silage harvest. Table 2 highlights the target crop moisture levels for an efficient fermentation that minimizes losses to seepage or mold. 

For a comprehensive review of best management practices for harvesting, storing, and feeding silage, please see From Harvest to Feed: Understanding Silage Management.