Iowa State University Extension staff recently started checking alfalfa fields for relative feed value (RFV) using the Predictive Equations for Alfalfa Quality (PEAQ) sampling method.
    Several Chickasaw County fields will be checked every Monday and Thursday until the fields are harvested. PEAQ is a research-based procedure to help alfalfa producers estimate the timing of their first harvest based on forage quality goals. The first alfalfa cutting is typically the largest harvest of the season and therefore of great economic importance to alfalfa and livestock producers.
    The PEAQ measurements taken are specific to those alfalfa fields and producers must check their own fields for a more accurate indicator of their first harvest timing.
    In addition, degree-day information indicates that alfalfa weevil larvae should be hatching in northern Iowa and Extension staff also will be scouting fields for the beginning of that hatch.
    Scouting should begin at approximately 250 degree days in fields in this area starting on south-facing hillsides where larvae will hatch first. These areas warm up more quickly than north-facing hillsides.
    According to Extension Specialists Rich Pope and Jon Tollefson, management of alfalfa weevil depends upon proper identification, timely scouting to determine populations, and if needed, early cutting or spraying with an insecticide. These larvae can cause significant damage to first-cutting alfalfa, so fields should be scouted.
    Currently, all alfalfa fields are in the vegetative stage and most fields are not tall enough to obtain a RFV estimate. Alfalfa plant heights range from 4 to 8 inches in Chickasaw County.
    A year ago at this time, plant height was over 10 inches. Variability is dependent on many factors:  variety; soil type, fertility, and moisture; previous harvest intervals and fall harvest activities.  It is important for producers to measure their own crop. A PEAQ handout is available from your local county extension office for producers to measure their own fields.
    On average, alfalfa quality will drop three to five points in RFV per day in spring. It is recommended to produce alfalfa forage around 150 RFV for milking dairy herds, and 120 to 130 RFV for heifers, stocker cattle and lactating beef cattle.   Under typical harvest conditions, 15 percent of the forage dry matter will be lost. Therefore, it is necessary to cut at PEAQ readings of 165 to 170 RFV to end up with harvested forage of approximately 150 RFV. Grassy fields will reach the stated maturity earlier than pure alfalfa. Alfalfa on lighter soils and southern slopes will also reach maturity faster.
    For more information on PEAQ contact the Chickasaw County Extension Office at 104 E. Main St., New Hampton, or information can be accessed on the Web at www.extension.iastate.edu/chickasaw.