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Introduction of new laser-guided intelligent spray control system

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Content Author:
Heping Zhu

This intelligent spray technology is a target-oriented spray control system. It is a product of a decade’s worth of research and development in collaborations with researchers and extension educators from USDA-ARS and many universities.

 

We designed it as a universal retrofit kit for conventional standard sprayers. With the retrofit kit, growers can upgrade their sprayers to precision sprayers rather than buying new sprayers. Smart Guided Systems (https://www.smartapply.com/) commercialized this intelligent spray technology in 2019 under the name “Smart-Apply” with many user-friendly features.


Universal intelligent spray control system

The system includes a laser scanning sensor to measure individual tree foliage volume, pulse width modulated (PWM) solenoid valves to control flow rates of individual nozzles, a GPS navigation device to measure sprayer travel speeds, a flow controller to activate PWM valves for nozzles to discharge variable spray rates, a Wi-Fi router for remote data transfer, and an Android Tablet display for the operator to communicate with the spray control system. To mount the retrofit kit on a sprayer, each nozzle needs to be connected with a PWM valve, and all other components are attached to the sprayer body without changing the sprayer structure.

 

The laser sensor has 270-degree and 164-ft radial detection range. It detects 54,000 points every second. Because of its high resolution and accuracy, an algorithm was developed to measure foliage volume at different part of each tree, and then control each nozzle output for the corresponding part of the tree. Sprayer travel speeds are also included in the spray output calculation, so applicators do not need to worry about how fast they drive. However, we don’t suggest travel speeds higher than 5 MPH for orchard spray applications.


Use tree foliage volume to control each nozzle output

 

With the retrofit kit, sprayers can “see” individual tree shapes, measure their size and foliage density, and then control each nozzle to spray the amount of chemicals to match foliage volume at different part of each tree in real time. Nozzles will be automatically shut off when no canopy is there.

 

The Intelligent Sprayer reduces the need for the person doing the spraying to make decisions on how much spray volume is needed. Thus, the complicated calibration process for conventional standard sprayers is avoided. The goal of the Intelligent Spray system is to maintain the same amount of spray volume per cubic feet of foliage volume for every tree. This takes the place of a conventional sprayer’s constant rate of a uniform number of gallons per acre.

 

Since 2013, we have tested pest control and reliability of this new technology in commercial fields of different crops across the country. These crops include apple, peach, grape, pecan, blueberry and raspberry. Multi-year field tests demonstrate that it can reduce pesticide use between 30 and 85%, reduce airborne spray drift up to 87%, and reduce spray loss to the ground up to 90%. Growers have reported chemical savings in a range of $56 to $812 per acre annually, depending on crop type, while their level of pest and disease controls is equal to that of conventional sprayers. Because it uses less spray volume per acre, the Intelligent Sprayer can spray more acres per tank of spray mixture, thus reducing tank refilling times.

 

Citrus, apple, grape, pecan and nursery growers in the United States and other countries are now upgrading their sprayers with the commercial “Smart-Apply” product. It saves growers money, cuts environmental damage and health risks due to spray drift, and it offers a sustainable and environmentally responsible approach to protecting crops.

 

You can see that this new technology is off to a strong start. However, to make the technology more versatile and adoptable, it must comply with different environmental conditions and it must be part of the regional IPM programs. The current USDA-CPPM project is digging deeper into its optimal application for pesticide spraying in Midwest orchards – specifically, how it fits into Midwest apple IPM programs, and how its affordability relates to orchard sizes.