Cut it out! Avoid alfalfa quality guesswork – Nathan Hrnicek, Vita Plus

By Nathan Hrnicek, Vita Plus forage products specialist
A late spring and plenty of rainfall is the perfect combination to make producers question when they should harvest first-crop alfalfa.  Two great methods to help predict crop quality prior to harvest are the PEAQ stick and scissor clippings.

The PEAQ (Predictive Equations for Alfalfa Quality) stick is a great tool for the first harvest of the year.  It is a four-sided stick that you use to get a current prediction of the alfalfa quality based on the current growth stage.  For help using a PEAQ stick, contact your Vita Plus consultant.

The second method, the scissor clippings method, can be used for all subsequent cuttings. The process to accurately take scissor clippings is detailed below.  To use the data you receive from your scissor clippings, you will need to establish harvest goals (RFQ values) and then make adjustments for harvest losses, time of harvest, and local field conditions.  During the adjustment process, it is important to remember that alfalfa will lose about four to five RFQ units each day.  Also, research indicates that 10 to 15 percent of dry matter (DM) will be lost during harvest under the best conditions.  Finally, you must factor in field conditions, such as soil types, age of stand, and purity of alfalfa versus mixed species.

Just like anything else with alfalfa, the scissor clipping method must be done at the correct time to help determine the optimal date for harvest.  This process should be done shortly after the first buds are present throughout the field to give adequate time for the processing and interpretation of the sample.  Here is an outline of the scissor clippings method:

Materials needed

• Square foot tool
• Small, non-metal bucket
• Sample bag
• Garden shears

Process

1. Choose a random spot and drop the square foot tool.  Pull all stems through square foot tool.  Note the number of stems to determine if you have an adequate stand.  Using shears, cut samples at the height of the cutter bar.
2. Cut the group of stems into the bucket in 1-inch sections.
3. Repeat this process for every 10 to 15 acres of the field.
4. Thoroughly mix the contents of the bucket to generate a sample to send to laboratory.
5. Send the sample to a forage testing lab for analysis.

Once you receive the analysis data from the lab, you can calculate the current RFQ by taking the RFQ from the sample and subtracting four to five units per day since the sample was taken.  You will also need to subtract potential harvest losses to determine the best day to harvest.  Here is an example:

• Sample RFQ from lab: 230 points
• Four days since sample taken: 20 points
• Current RFQ: 210 points
• Harvest losses (15 percent x current RFQ (210)): 31.5 points
• If harvested today: 178 points

Contact a member of the Vita Plus forage team with any questions you may have.  Remember, high-quality forage is where sound nutrition starts!