The SCNY team is going to monitor alfalfa heights again this spring to help predict quality and %NDF. Alfalfa height has been proven to be a reliable indicator of NDF values in the field for alfalfa, alfalfa/grass mixed stands, and all-grass stands. The team wants to identify fields that can be measured on a weekly basis. If you have fields that we can come out and measure, please let Janice or Betsy know! Results will be compiled on a weekly basis – to receive weekly email/text updates, please contact us at 607.391.2673 with your email address/cell phone number.
The numbers that are indicators for using alfalfa heights for NDF content are as follows:
- 100% grass stands should be cut when nearby alfalfa is 14 inches tall, to achieve 50% NDF.
- Begin cutting 50/50 mixed alfalfa/grass stands when nearby alfalfa is 22 inches tall, to achieve 44% NDF.
- Begin cutting 100% alfalfa stands when alfalfa is 28 inches tall, to achieve 40% NDF.
- Predicted days to cut are based on daily NDF increases for grasses of 1.0% point, 50/50 mixed alfalfa/grass stands of 0.8% points, and pure alfalfa of 0.5% points. Predictions are adjusted for the coming week’s weather.
- Typically NDF increases about 0.8 to 1.2 per day for grasses, with cooler weather being the lower end of the range and warmer weather being the higher end.
- For alfalfa, NDF increases about 0.4 to 0.7 per day, also dependent upon warm/cool weather.
The weekly email will have a table of the locations around the region where we have measured the alfalfa height, as well as the elevation, and target date for harvest. Even if your fields aren’t measured, you can use the location and elevation as a guide to conditions that may be similar to your own.