By Dan Martens, U-M crops educator Forage growers and advisers can use several strategies for gauging alfalfa growth and maturity for harvest decisions to meet feed needs. These include PEAQ sticks, scissors-cut sampling, monitoring height and maturity, calendar dates and watching the weather.
By Dan Martens, U-M crops educator
Forage growers and advisers can use several strategies for gauging alfalfa growth and maturity for harvest decisions to meet feed needs. These include PEAQ sticks, scissors-cut sampling, monitoring height and maturity, calendar dates and watching the weather.
PEAQ--Predictive Equation for Alfalfa Quality—is based on the height and maturity of the alfalfa. The PEAQ stick was developed at University of Wisconsin with numbers marked for relative feed value or relative feed quality related to height and vegetative bud and blossom stages. PEAQ sticks can be purchased through the Midwest Forage Association website www.midwestforage.org or by calling (651) 484-3888.
Scissors-cut sampling means taking a fresh-cut sample at random locations in an alfalfa field and having the sample analyzed at a forage testing lab. The recommendation is to take at least three samples at three-to-four-day intervals ahead of when the alfalfa might be cut to estimate a trend for how the crop is developing. Cutting decisions are usually based on neutral detergent fiber, RFV or RFQ.
Because of harvest and storage losses, harvest should start when the PEAQ or lab test NDF numbers are three to six points lower and RFV/RFQ numbers are 10 to 25 points higher than goals for alfalfa feed in the feed manger. The margin allowed can depend on the time needed to complete harvest.
Weather is a key factor. Growers need to have equipment ready and look for a break in the weather that gives them a chance to get close to feed quality goals. Past experience is also a good indicator of whether strategies are working well on farms or adjustments might be useful.
To help growers watch for the first hay harvest, University of Minnesota Extension staff in central Minnesota counties work with farmers and business representatives to sample selected fields on Mondays and Thursdays starting around May 15. The results will be posted on Extension's Minnesota Crop News website at www.extension.umn.edu/cropnews and reported on some local radio stations.
Direct questions about this project to Extension's Farm Information Line (Phone: 800-232-9077; email [email protected]).
For more information, visit Extension's forages website at www.extension.umn.edu/forages.