Wisconsin leads the nation in corn silage production, harvesting over 20 million tons of silage (at 65% moisture) on approximately 970,000 acres in 2020. Corn silage is unique compared to multi-cut forage systems, such as alfalfa, as there is a single opportunity to properly harvest and store quality forage each year. With such high stakes riding on harvest management decisions, farmers and consultants must diligently monitor crop maturity and moisture to optimize harvest timing to balance silage yield, ensiling conditions, and forage quality.
The 2021 growing season has been highly variable across the state. While planting conditions were optimal for most areas of the state, many fields suffered a setback with a late season frost, resulting in variable plant dieback and uneven stands. Additionally, western and southern portions of the state have endured season-long drought with much of the remainder of the state receiving timely, yet inconsistent and often torrential, rainfall. These weather challenges have resulted in significant variability in crop growth, maturity and dry down, both from field to field and within individual fields.
With such crop variability, it is imperative farmers and consultants regularly monitor corn silage acres to properly time harvest activities. Harvesting silage at the proper moisture content for the intended storage structure allows for the proper packing and ensiling, reduces forage spoilage, and minimizes the production of leachates. Whole field moisture content, as well as areas of differential dry down within a field, should be documented in order to develop a harvest strategy to ensure the average moisture content of the packed forage is consistent and within an acceptable range.
Crop moisture levels can be determined by bringing whole plant samples to silage dry down events commonly hosted by regional Forage Councils and agriculture cooperatives. In addition, chopped samples can be submitted to local testing laboratories. Moisture test results from many area silage dry down events co-hosted by UW-Madison Division of Extension are available at https://fyi.extension.wisc.edu/silagedrydown/.
Monitoring crop moisture status and developing a harvest strategy, particularly for stressed and uneven fields, will help preserve forage quality and yield.