Corn Silage Dry-Down: Week of September 8, 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.
| County | Hybrid | Planting Date | Sampling Date | Moisture Content | Accumulated GDD | Precipitation Deviation | GDD. Deviation |
|---|---|---|---|---|---|---|---|
| Centre | 88 RM | 4/29/25 | 9/9/25 | 62.10% | 2239 | +1.13" | 33.00 |
| Centre | 101 RM | 4/29/25 | 9/9/25 | 65.00% | 2239 | +1.13" | 33.00 |
| Centre | 105 RM | 4/29/25 | 9/9/25 | 69.00% | 2239 | +1.13" | 33.00 |
| Franklin | CH207-27STX | 6/6/25 | 9/9/25 | 70.50% | 2207 | +1.06" | -111.00 |
| Franklin | CH213-23STX | 5/27/25 | 9/9/25 | 69.50% | 2332 | +2.85" | -150.00 |
| Wayne | 101 RM | 5/30/25 | 9/9/25 | 75.00% | 1930 | -4.58" | 102.00 |
| Wayne | 94 RM | 6/30/25 | 9/9/25 | 80.00% | 1387 | -6.79" | 19.00 |
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 this week's observations, dry-down rates have averaged about 0.0%.Â
Be cautious of localized differences in planting date, hybrid maturity, and weather conditions. Extended wet weather this spring has led to large variations in planting dates across the state, and some farms may have to prepare for managing several harvests this fall if crop maturity varies excessively. Be aware of expected weather in the coming weeks; if cooler weather trends continue into September, crop maturation may slow considerably. Table 2 highlights the target crop moisture levels for an efficient fermentation that minimizes losses to seepage or mold.Â
| Structure | Whole-Crop Moisture % |
|---|---|
| Horizontal Silo | 65-70% |
| Conventional Upright | 63-68% |
| Oxygen-Limiting Upright | 55-60% |
| Bag | 60-70% |
| Pile or Stack | 65-70% |
For a comprehensive review of best management practices for harvesting, storing, and feeding silage, please see From Harvest to Feed: Understanding Silage Management.
