Crop Estimation and Thinning Table - Dr. Terry Bates
Collecting a little bit of information from the vineyard during the growing season can greatly improve your prediction of final yields with better accuracy than the eyeball method. Know your Bloom Date, Space Between Vines, and Space Between Rows. Calculate how many vines equate to 1/100th of an acre, and know how many Days After Bloom (DAB) samples were collected.
Example:
Row and Vine Spacing. If 9’ between rows, the table provides the 1/100th acre calculation for you, which equals 48.4 feet.
How many vines are in 48.4 feet if vines are spaced 8 feet apart? 48.4/8=6.05 vines (round down to 6).
Use Spatial Map to direct Sample locations to capture vineyard variation.
Clean Pick Fruit from Calculated 1/100th Acre (In this example, it equals 6 vines from 48.4/8). Clean pick fruit from 2 vines from the high vigor zone, 2 vines from the medium vigor zone, and 2 vines from the low vigor zone.
Total Weight (lbs) of Fruit Collected. Weigh each sample taken above, and be sure to subtract the weight of the bucket or bin used from the total weight. Sum the weights from all 6 samples to get the total weight.
Consult the Table to Find the Corresponding Crop Estimation.
Mechanical Crop Estimation
Cut a length of rope to guide your sampling lengths, lay it down along the row, clean pick with the harvester the length of the rope, and weigh the pounds of fruit collected. Walk behind afterwards to assess how many grapes are still on the vine and/or that are on the ground.
Using the chart: (Click Here for the Using the Concord Crop Estimation Chart)
Once you have the sample, the chart does the rest of the work for you. Follow the corresponding DAB down and the respective weight over, and you have the estimated tons/acre at harvest. For example, let’s say it’s July 25th or 40 DAB (bloom on June 15th) and the fruit weighs 100 pounds. Crop estimated at 8.3 tons/acre of potential crop. Click here for a PDF of this information.