The South Central NY Cornell Cooperative Extension team is monitoring alfalfa heights again this spring to help predict quality and %NDF for first cutting hay crop. Alfalfa height has been proven to be a reliable indicator of NDF values in the field for alfalfa, alfalfa/grass mixed and all grass stands. Results will be compiled and emailed on a weekly basis – please feel free to forward on. To be included on the weekly email, or to be removed from the email, please contact Betsy Hicks, firstname.lastname@example.org.
UPDATES FOR THE WEEK OF MAY 8th, 2017:
Comments from Janice: We measured slow growth with the wet and cold conditions of the last week. Our protocol is to measure the tallest alfalfa in the stand, but in older alfalfa and wetter fields, the alfalfa tends to be more uneven. Keeping this in mind, our field scale measurement should be ground-truthed as you plan for harvest. Grasses will be headed by next week so if you are harvesting grass or mixed stands for dairy quality they will be ready to mow in the next stretch of decent weather. Some lodging is beginning in alfalfa over 20”. No buds are observed yet in alfalfa. If you have mixed grass/alfalfa stands, refer back to the chart of percent of alfalfa vs grass (attached) and what height alfalfa is to determine when to harvest the field for peak quality. If you need help determining what percent your stand is, contact me at 607.391.2672 or email@example.com.
Comments for Southern Counties (Broome, Tioga, Chemung, S Cortland): Most fields saw no more than 2” growth in alfalfa, although some of the valley ground with favorable drainage and a southern slope did see more. In general, higher elevations and wetter fields only saw 1” of growth with the cool weather. Even so, predictions for harvesting 50/50 mixed grass/alfalfa stands are stating dairy quality harvest should begin by the middle of next week and grass stands should be harvested now. Fields in general are drier here than in the counties to the north. Some farms that have pure grass fields and some mixed fields to the east of our region have started harvest on fields that have dried out enough to drive on.
Comments for Northern Counties (Tompkins, N Cortland, Onondaga): In general, most all fields saw no more than 2” growth in alfalfa. Fields are very wet across the northern counties and will likely have some rutting around wet spots if they are to be harvested for dairy quality. Predictions for peak grass quality is to harvest now, 50/50 mixed grass/alfalfa stands are predicted to be peak at the end of next week, only a couple days behind the more southern counties.
Weather conditions for the coming week look like rain Saturday and Sunday, with warmer weather closer to 70 degrees next week. I know you all are frustrated with not being able to get corn in the ground, but the focus needs to be on harvesting hay crop at peak quality! Please let us know conditions you observe while harvesting, and any comments back about the alfalfa height project are appreciated! We also welcome any sample results you would like to share, so forward them on me, firstname.lastname@example.org. You can also post harvest pictures on our team’s Facebook page – https://www.facebook.com/SCNYDairyandFieldCropsTeam/ and use the hashtag #harvest2017.
Thank you, and be safe!
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
• 50/50 mixed alfalfa/grass stands should be cut when nearby alfalfa is 22 inches tall, to achieve 44% NDF
• 100% alfalfa stands should be cut 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 alfalfa of 0.5% points and 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 for the month of May will have a table of the locations around the region where we have measured the alfalfa height, as well as the elevation. 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. We now cover six counties throughout South Central NY, including Tioga, Chemung, Broome, Tompkins, Cortland and Onondaga. Other teams and associations throughout the state are also measuring fields. For more information, contact that county’s association to find out if fields are being measured there.
Betsy J Hicks
Area Dairy Specialist
South Central New York Dairy & Field Crops Team
Cornell Cooperative Extension
60 Central Ave
Cortland, NY 13045