CRESCO, Iowa — Calendar date is NOT a good decision tool to best determine when to harvest the first crop of alfalfa. Every spring, alfalfa growth and development is different due to climatic, variety, stand age and other management factors. The PEAQ method (Predictive Equations for Alfalfa Quality) developed by the University of Wisconsin takes these variations into account to roughly predict relative feed value (RFV) of standing alfalfa in the field to estimate when to harvest the first crop. The PEAQ website (https://www.extension.iastate.edu/dairyteam/peaq/ includes a fact sheet that explains this fast and easy method. A critical step with the PEAQ method is to understand that the reading from the field represents standing crop quality. You need to adjust this reading to account for harvest losses. Harvest losses equal about 15 RFV units for haylage harvest, and about 25 RFV unites for hay harvest. If you wanted to target 150 RFV alfalfa, it is recommended to harvest haylage or hay when the PEAQ measurements predict about 165 RFV and 175 RFV, respectively for the standing alfalfa field measurement.
— Iowa State University Extension and Outreach Howard County
For more news from Iowa, click here.