How to estimate alfalfa quality in the field using PEAQ

You can estimate alfalfa relative feed value (RFV) and neutral detergent fiber (NDF) levels with the Predictive Equations for Alfalfa Quality (PEAQ) system, which gives alfalfa producers a simple way to schedule harvests. A PEAQ stick can be a useful tool when implementing this approach.

The PEAQ stick is currently used in the central Minnesota Harvest Alert/Scissor Cut Program.

The PEAQ stick method was developed by the University of Wisconsin. Sticks can be purchased through the Midwest Forage Association RFV PEAQ stick order form.

How to sample using the PEAQ method

This procedure is most accurate for good stands of pure alfalfa with healthy growth. Follow these steps:

1. Choose a representative 2-square-foot area in the field.
2. Determine the most mature stem in the 2-square-foot sampling area using the staging criteria shown in the relative feed values (RFV) table below.
3. Measure the length of the tallest stem in the 2-square-foot area.
   • Measure it from the soil surface (next to plant crown) to the tip of the stem; not to the tip of the highest leaf blade.
   • Straighten the stem to accurately measure its length.
   • The tallest stem may not be the most mature stem.
4. Based on the most mature stem and length of the tallest stem, use the RFV table to determine the standing alfalfa forage’s estimated RFV content. Use the Neutral detergent fiber table to estimate NDF.
5. Repeat steps 1 to 4 in four or five representative areas across the field. For fields larger than 30 acres, sample more times.