Managing alfalfa fields in Michigan is far different in the southern tier of counties compared to the top of the Upper Peninsula. This should not be a surprise given it’s about the same distance to drive from Waldron, Michigan, located near the Michigan/Ohio state line, to either Marquette, Michigan, or Nashville, Tennessee. To provide beginning and experienced alfalfa producers with some guidance, Michigan State University Extension has produced an Alfalfa Management Calendar for Michigan. The calendar is also available on the MSU Forage Connection website and can be downloaded free.
The calendar breaks the state into four regions from top to bottom. For each of the featured regions there are management timing tips for the following areas:
- Spring and fall fertilizer applications
- Scouting for insects
- Average cutting dates
- Average fungicide application times
- When to avoid cutting in fall
The major differences that drive management options between regions within Michigan are soil textures, precipitation and temperatures patterns influenced by the Great Lakes. This makes it challenging to divide Michigan cleanly into regions. Remember, this calendar is about averages for each region, and adjustments may need to be made for localized environments.
The harvest timing schedule for first cutting is tied to temperature measured as growing degree-days (GDD), and MSU has current weather data available on the MSU Enviroweather website in the Field Crops > Resources section. The website includes an Alfalfa Cutting Model under Field Crops. This model provides estimates of the best timing for harvesting first cutting for a particular location based on GDD accumulation at the nearest Enviroweather station.
The Alfalfa Weevil Development monitor tool provides guidance to start scouting for weevil adults when temperatures are greater than 48 degrees Fahrenheit. This tool is also based on the accumulation of GDDs. Crop scouts and farmers can access the Alfalfa Weevil Development model found on the Enviroweather website in the Field Crops > Resources section. Be careful not to use the same GDD model for alfalfa harvest timing and alfalfa weevil development because these two prediction tools use different temperature scales.