Variable Rate Shoot Thinning in Concord Vineyards for Increased Production Efficiency

Grape growers have long seen wide ranges in productivity across their vineyards, but by the time the yield was measured it was too late to manage for improvement. With precision variable rate shoot thinning, that’s no longer true.

This article was developed for the 2016 NYFVI annual report. More information can be found here.

Dr. Terry Bates and his team at the Lake Erie Grape Program wanted to learn if they could use sensors to map vine canopy growth in Concord and Niagara vineyards to generate an accurate spatial crop estimation map. Understanding yield potential based on the canopy would allow growers to manage the vines for optimum productivity using variable rate shoot thinning.

The answer was a clear yes.

A balanced crop load is critical in perennial crops. Overcropping, that is allowing the vines to produce more fruit than they can sustain, limits the next season’s crop and can damage vines. Shoot thinning practices that result in under cropping means the vines aren’t reaching their full yield potential. The goal for the project was to determine if yield variability in a vineyard could be reduced by as much as 35% while increasing the overall yield by 25%.

The first step was to determine if a map generated by sensors measuring canopy growth could be integrated with existing knowledge about vigor classification and soil data to generate an accurate crop estimation map. The work was done, and the map was validated against the actual harvest data collected by a yield monitor.

“Past viticulture research has shown the importance of crop management in sustainable quality grape production. Innovation in equipment has demonstrated how proper crop management can be achieved through cost-effective vineyarda mechanization options. We are happy with the progress on this project where we have integrated desired crop management decisions with mechanized implementation through data-driven variable-rate mechanized shoot thinning.”

Dr. Terry Bates, Lake Erie Research and Extension Laboratory, Director
Cornell University

In addition to working out the sensor maps, the team knew they needed equipment to be able to implement their idea. They worked with an equipment dealer to integrate a GPS unit, prescription map software, electronic variable rate controller, hydraulic flow controlled, and flow meter with the mechanical shoot thinner. Once the equipment was in place, tests were conducted to determine the effect of paddle speed on the level of shoot removal for the next season trials.

The project also developed spatial canopy and soil maps for 700 acres in commercial vineyards to determine where to conduct the 2016 variable rate shoot thinning trials.

Next, the team moved on to implement and test variable rate shoot thinning. This management practice connects the GPS technology in the tractor to the crop estimation map allowing the operator to precisely thin the vines to regulate crop load early in the season.

Working with two 5-acre commercial Concord blocks and one 5-acre research Concord block, variable rate mechanical shoot thinning was applied across three management zones with the goal of achieving a balanced crop load. Paired sub-plots within each vineyard and management zone were compared: no shoot thinning, uniform shoot thinning, and variable shoot thinning.

The variable rate shoot thinning system works so well because it provides the information the grower needs to customize their shoot thinning practices based on the exact position of the equipment in the field.  At harvest, the yield information is collected and fed back into the analysis to allow the grower to focus on the trouble spots in the vineyard in the next production cycle. Research shows a $1125 range in profitability per acre across a 20-acre block.  Managing each part of the vineyard for its full potential will create more uniform productivity and profit.