Tips for Scissor Cutting Alfalfa

From weather patterns to other fieldwork to insect infestations, many factors can impact when you decide to harvest alfalfa. But if your goal is to harvest based on feed quality, understanding alfalfa’s Relative Feed Value (RFV) is key.

You can measure RFV by taking regular field clippings and analyzing samples. This sampling method is known as “scissor cutting” and it can help you determine the best time to start harvesting alfalfa. It is important to stay consistent and ensure samples are representative of your fields.

Here are six steps to follow when scissor cutting alfalfa:

1. Start sampling in mid-May; or when alfalfa is about 14-inches tall.
2. Sample on Mondays and Thursdays so lab results are available on business days. You don’t want to let the crop sit over the weekend while waiting for results!
3. Stay consistent with the time of day; before 8 a.m. is preferred. This helps reduce day-to-day variability.
4. Sample two, 2-square-foot areas that are representative of the field. Then choose 5-6 different plants in each area. Be sure the selected plants are random, not just the largest.
5. Cut 2-3 inches above the soil and collect about a half-pound of fresh weight per location.
6. Place samples in a paper bag and send to a forage quality testing laboratory. Dairyland Laboratories is a good testing resource in the Midwest.

We recommend cutting alfalfa when RFV hits 170 to get RFV of 150. It will lose about 15-20 RFV points during harvest or about 4-5 RFV points per day depending on the weather.

The PEAQ system is a good tool for estimating RFV in conventional alfalfa without having to use a lab. The method is based on measuring the tallest and most mature stem in a 2-square-foot sample area, then using this table to find an average RFV. If you are using reduced lignin products, the PEAQ measuring method may not be as accurate.