Using Drones to Manage Orchards

Commodities

Practices

With increasingly erratic weather patterns and more periods of heavy rain, it is difficult to get into the orchard early enough in growing season for effective scab management. Scab is the primary fungal disease of apples and it requires intensive management early in the growing season: first with a tractor and flail mower to pulverize prunings and then second, to get into the orchard with a tractor and an airblast sprayer to apply copper, an organic fungicide. Using a drone to apply copper in dormant conditions eliminates the need to take a tractor through the orchard in wet, early spring conditions thereby minimizing soil compaction, erosion, and general deterioration.

The potential benefits of using a drone for orchard crop management can be taken further into the growing season as well:

• Further reducing soil deterioration by avoiding tractor and sprayer use,

• Reducing the use of non-renewable fuel sources

• Reducing the volume of insecticides used on the farm

• Decreasing the time it takes for pesticide applications

Solution

The project aims to explore a means of orchard management that is potentially more sustainable than the conventional tractor-and-airblast-sprayer means of crop management that most apple growers use. Using a drone has sustainability benefits in terms of fuel (diesel versus electric), reduced soil deterioriation from erosion and compaction, reduced material use, and a reduction in the time it takes the farmer to apply pesticides. There are some challenges associated with using a drone for orchard management and this project attempts to address those challenges.

The project will assess spray patterns, spray height, material types, and spray volumes by isolating a single variable toward the purpose of being able to specify best practices in using a drone for orchard management. After determining the suitability of different material types, we will designate which orchard-relevant products are suitable in orchard production. All experimental conditions will be performed at the same orchard with two different one-acre plantings:

• Orchard #1 has young trees (4-8 years old) planted on trellis in a tall spindle system with 3’ between trees and 12’ between rows.

• Orchard #2 has mature trees (25 years old) planted on a central leader system with 6-8’ between trees and 16’ between rows.

In each of the following conditions, we will hang spray pattern test paper at twelve points:

• at the four corners;

• at four points in the middle of border rows;

• at four equidistant points n the middle of the orchard block

Each point will have three spray pattern test papers:

• at low branches approximately three feet from the ground;

• at middle branches approximately six feet from the ground;

• and at upper branches approximately nine feet from the ground.

Experimental condition #1: Spray Orientation

The purpose of these experiments is to understand which spray orientation is ideal in an orchard:

• Directly over trees

• Between rows

• Perpendicular to rows

• Diagonal to rows

Experimental condition #2: Spray Height

The purpose of these experiments is to understand how far above the trees the drone should fly for ideal material penetration:

• 2 feet

• 6 feet

• 10 feet

• 14 feet

Each experimental condition will be assessed by the following measurements:

• Time (therefore battery use)

• Spray penetration

Once the ideal spray orientation and height is established, the experimental program will turn to determining which material types and spray volumes are suitable for orchard management, which again will be assessed by using spray pattern test paper to measure penetration.

Material application

• Material types (for example, water dispersable granules/dry flowables, wettable powders, liquids, emulsifiable concentrates)

• Spray volume, for example, 4 gallons per acre versus 8 gallons per acre (for reference, airblast sprayers use 50-100 gallons per acre)

Objectives

• Determine optimal spray coverage patterns and spray heights for central leader and tall spindle orchards for management with a spray drone.

• Determine which material types are best suited for application with spray drones.

• Develop a cost/benefit analysis that growers can use to determine if management via drone is the right choice for their orchards.

• Develop a guide for best practices orchardists can use for orchard management via drone.