By Thom Betts and Kim Knappenberger
In his last blog (January 18, 2017), Thom Betts of Betts Farms LLC introduced you to his family, their farm, and their perspective on this project as it relates to their farm. During this past year Thom and his parents, Bob and Dawn, were able to dig a little deeper to do some innovative work with “on-the-fly” fruit thinning technology. He recalls that 2 summers ago they only did variable thinning on 10 acres of grapes to see if it worked on the small scale. In 2017 the Betts performed their usual crop estimation with NDVI scans that gave them their management zones and then they validated that information using the harvester to clean pick a specific length of the row. (see the Current Research article Spatial Data Driven Concord Crop Estimation and Adjustment – July 2016) Due to the wet spring early on, they concluded to thin 60 acres of grapes, or 1/3 of the farm.”
Thom’s thinning efforts are made both for continued vine health, and in order to be able to attain the sugar standards required by their processor, National Grape Cooperative, when harvest begins. The Betts like to be able to begin trucking their grapes to the processing plant on the first day of harvest. In order to do this, they thin their crop with the use of their field computer (which runs the picking heads of the harvester), GPS unit, and a yield monitor. The management zones established by the NDVI scans are entered into the field computer and the appropriate RPM levels for the picking heads are established for each zone, that then remove the amount of crop desired for each zone. For the Betts, the amount they wanted to remove was 0-3 tons per acre depending on the management zone. The amount removed was measured by the yield monitor on the harvester and then verified through the use of a field scale. Calibration had to be done mid-thinning due to the lighter berry weight at 30 days after bloom (DAB) than at harvest, but once it was corrected thinning went as expected in all zones.
This harvest the Lake Erie region was blessed by mother nature with warm, dry days. All 180 acres of the Betts’ vineyards were harvested in the first 16 days that the processing plant was open. This was a definite result of the thinning – it allowed their large crop to accumulate sugar at a more rapid pace and reach industry standards earlier than their colleagues that did not thin large crops.
Going forward Thom is planning to continue this variable rate thinning practice. They are going to work on breaking down the economics over the winter so they can move forward with a solid plan when the growing season begins. “Overall we are very happy with the results. Again this year we came within 5% of our crop estimation, and we picked the exact crop that we thought we had. All in all it was another successful year on the farm.” Thom has also reported that they are finding excellent wood quality during their dormant pruning and are hopeful to see the positive impact on building vine size in the coming growing season.