First Cutting Monitoring – May 5th, 2020 SCNY Report

GDD Map of NY

This is the SCNY Team’s first full week of monitoring alfalfa heights for first cutting quality in 2020.  A full report for the six-county region can be found in the following link: Alfalfa Height Reporting Sheet 5.5.2020.

On Thursday, May 7th at 12:30, the team will be hosting a webinar on 2020 First Cutting Updates.  The link to follow the slides can be found at:  Dial in numbers to join by phone are:  +1 646 876 9923 US (New York), Meeting ID: 973 1278 0153.

Team Agronomist, Janice Degni, will go over updates to soil and weather temperature maps, and Betsy Hicks, Dairy Specialist with the team, will go over this week’s report.  Staging this year’s harvest with other crop work will also be covered for producers in our region.

In general, fields in our region average between 8-9” tall, with the exception for fields in northwestern Onondaga county, which measured 12-14”.  Normally, fields in southern Tioga and Chemung counties are well ahead of those counties to the north, but pockets of accumulated growing degree days (GDD) are spread somewhat differently this year than in the past.  The next two pictures are courtesy of John Winchell of Alltech.

NY Growing Degree Days (B32) 2019 v 2020

GDD Map of NY


Cornell’s Climate Smart Farming tool ( can be utilized to determine GDD by location.  For grass determination, I selected base 32, and inputted several locations across our region.  As John Winchell from Alltech states, all grass fields should be harvested at 900 DGG.  The tool predicts a date to accumulated GDD by location, and shows that a few locations as referenced above will have grass fields close to the needed GDD by 5/12 – 5/15, but many locations will be well into the 5/20 before locations achieve 900 GDD.  We will monitor this tool, as well as our height predictor report, to target peak quality for both grasses and alfalfa.

GDD (B32) by location


GDD (B32) by location

As always, heat will rapidly change the growing crop.  This year, the ability to be nimble is again of utmost importance in getting our first crop in at peak quality.  Corn is being put into the ground in many locations, but when grass is ready, the crop crew needs to be ready to harvest.

As a reminder, for prediction of NDF content, the height of alfalfa as an indicator is as follows:

  • 100% grass stands – cut when nearby alfalfa is 14 inches tall (achieves 50% NDF)
  • 50/50 grass/alfalfa stands – cut when nearby alfalfa is 22 inches tall (achieves 44% NDF)
  • 100% alfalfa stands – cut when alfalfa is 28 inches tall (achieve 40% NDF)Alfalfa height at optimum mixed stand NDF

From Kevin Ganoe, the CNY Dairy, Livestock & Field Crops Team’s Forage Specialist:

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.

Look for our next report of monitoring heights to come out on Wednesday, May 13th.  In the meanwhile, if you can’t get out to check your fields, call one of us on the team.  We’ll be glad to help out.


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