2014 Green County Alfalfa PEAQ Readings

2015 alfalfa maturity readings in the Green County were running ahead of the 5 year average as of May 12. According to Degree Day calculations for 2015 alfalfa weevils will start appearing at 300 GDD’s or around May 10th in southern WI. They will do most of their damage in the 3 & 4 in-star stages when we reach 500-600 GDD’s. It’s recommended to cut, and not spray, for control of weevils when we reach a threshold of 40% tip feeding damage.

Area dairyman and livestock producers can get a gauge on when to cut first crop by following the “Predictive Equations for Alfalfa Quality” (PEAQ) method, which predicts optimum dates for first cuttings by monitoring plant development and quality. The PEAQ technique, developed by the University of Wisconsin-Madison, is a proven, low cost, method for instantly estimating forage quality of standing alfalfa. PEAQ consists of predicting fiber and relative feed value (RFV) based on the height of the tallest stem and the stage of plant maturity in a sampling area. The first harvest is typically the highest yielding yet most difficult crop to put up in a timely manner. The PEAQ stick provides a simple, effective look to schedule your harvest to achieve forage quality target levels.

Since approximately 15 to 20 RFV units are lost during harvest and storage, alfalfa needs to be cut at 165 to 170 RFV calculated using PEAQ to have 150 RFV of harvested forage, which is recognized as high quality alfalfa. RFV of 170 in the field equates to alfalfa 26-27 inches tall and in the bud stage.

A change in RFV of 3 to 5 points per day in the standing forage has been noted, so adjustments are needed for total harvesting time, meaning that alfalfa may have to be harvested prior to a PEAQ value of 165 to 170. Producers need to balance decisions based on the PEAQ technique with short-term weather forecasts and field conditions.  PEAQ predictions are most accurate for good, healthy stands of pure alfalfa.

2015 Green County Alfalfa PEAQ Readings

Date

Field A (4th Year Stand)

Field B (3rd Year Stand)

 May 9 Ht. = 17.5″  RFQ=228  Ht. = 21″  RFQ = 208 
May Ht. =    Ht. =   RFQ =
May  Ht. =   RFQ = Ht. =    RFQ =
May Ht. =      RFQ = Ht. =     RFQ =
May Ht. =     RFQ=   Ht. =    RFQ =
25% of Plants @ Bud Stage
 May Ht. =     RFQ =
75% of Plants @ Bud Stage
Ht. =   RFQ =
100% of Plants @ Bud Stage
 May
(Final 2015 Reading)
Ht. =      RFQ =
100% of Plants @ Bud Stage
Ht. =      RFQ =
100% of Plants @ Bud Stage

* First sign of alfalfa weevils.