This fact sheet authored by PRO-DAIRY forage systems specialist Joe Lawrence was shared in the August 2024 PRO-DAIRY e-Leader newsletter, distributed to an email list of nearly 7,000 dairy producers, agriservice, and legislators.
Despite all the variable and often extreme weather this season, the general narrative is of above average heat, and speculations of an early corn silage harvest. When looking at the growing degree day (GDD) accumulation for the growing season, locations across New York and the Northeast are well ahead of the 15-and 30-year averages. Using the Climate Smart Farming Growing Degree Day Calculator and data from locations across the state (with a May 10 example planting date) the season is 100 to 200 GDD’s ahead of the 15-year average through August 10.
Comparing data from the last three growing season at Corn Silage Hybrid Evaluation Program locations gives a relative comparison of the 2024 crops progress. The number of calendar days from planting to tasseling are lower than the previous two seasons, however, the difference varies by location. While this is expected as average GDD accumulation per calendar day is higher this year, the GDD’s needed to reach tasseling also varies pointing to the influence of other growing season factors in the crops progress.
The story is slightly different when considering crop progress since tasseling. Regardless of what happens pre-tasseling, the corn crop needs a certain number of growing degree days from tasseling to silage harvest and that is where our attention should turn now. If you observed an earlier tasseling date, that certainly sets the stage for the potential of an earlier harvest; however, it is not a direct relationship. For example, if a field tasseled 10-days earlier than a “typical year”, that does not directly translate to a 10-day earlier harvest date. The weather in late July and August will still influence how rapidly the crop matures. While all locations reported were well ahead of average in GDD accumulation since planting, the progress since July 20 (example tasseling date) ranges for five GDD’s behind the 15-year average (Canton, NY) to 62 GDD’s ahead (Argyle, NY). Given the average number of growing degree days per calendar day, that already represents a difference of between zero and four calendar days.
As we move through August, it will be important to be prepared for the crop to reach harvest maturity earlier than normal, but it will be equally important to monitor actual crop progress and make harvest timing decisions based on target stage of maturity. Potentially a bit of a “hurry up and wait” scenario but better to be ready when the crop is ready.
Considerations and resources
- Review harvest plans with your team, including equipment, safety and storage.
- Determine if crop variability (due to disruptions in planting window or other factors) necessitates a staggered harvest schedule and different storage strategies.
- Understand differences in plant and ear dry down to refine harvest timing decisions.
- High rainfall during the growing season tends to negatively impact fiber digestibility. Across the region, the 2023 season was a mixed bag for fiber digestibility. Based on weather patterns to date, it is unlikely fiber digestibility will be better in 2024. Be prepared for similar or lower digestibility in your 2024 corn silage and work with your nutrition team on how this will influence rations when you begin incorporating this corn silage into diets.
