Intelligent Spraying Equipment can now use GPS (Global Positioning System) to detect and locate different soil conditions in large fields, and is a by-product of the guidance and probing systems developed for the space program.

Now look at Sonar and Laser technology being applied to sprayers to detect the targets and direct the spray specifically at the plants and trees that have to be treated, rather than just blowing a continuous cloud of spray into the air: it comes from military targeting systems developed over the years and fully proven in the Gulf War.

Yes, there are sprayers on the market and presently in use by progressive growers that actually look at the plant and turn on the nozzles according to the shape and position of that plant. They are even so smart that you can program them to open a little before and close a little later to compensate for wind conditions!

Get used to names like "Smart-Spray", "Tree-See" and "Tree-Sense". They are all presently available and can be even retro-fitted to most of the existing air-blast machines.

How do they work? At present there are two systems:

The Laser "Tree-Sense" offered by AgTech. This is a three dimensional image range sensor originally designed for imaging enemy tanks in Desert Storm.

With a single scanner, mounted in the front of the sprayer, it can map the image of a tree up to 100 feet away on either side of the sprayer.

In doing this, it feeds the size, height and location into the onboard computer. Eight inches before the leading edge of the tree, the computer opens the necessary sprayer orifices to totally spray the tree and shuts them off eight inches after the trailing edge. The spaces in between are not sprayed.

The nozzles are controlled by electric solenoid valves which are set up in zones so that only the foliage detected by the scanner is sprayed. This system can be retrofitted to Agtec Sprayers with standard orchard heads.

The "Sonar" or ultrasonic system was invented by Bert Roper as the "Tree-See", in 1982, and has been selling in Florida since the first unit was purchased by Coca Cola Foods in 1984.

It is now offered as the "Smart Spray" by Durand Wayland and as a retrofit for existing, FMC, Durand Wayland, Aero Fan and other major brands of air blast sprayers by its developer, Roper Growers Coop. of Winter Garden, FL.

The Sonar system uses ultrasonic impulses to detect the presence or absence of trees and plants. This detection is done by sensors installed on each side of the sprayer that can be aimed in any desired direction to cover optimum zones, according to the crop being sprayed.

The models range from a one sensor (small tree) unit to a ten sensor model (five sensors per side) that can cover trees up to 40 ft high and is usually recommended for Towers and Oscillators. These sensors have a range of 25 feet so as not to detect targets over in the next row. Tree-See systems can also be used on fertilizer spreaders (both dry and liquid) and herbicide applicators.

The Tree-See/SmartSpray systems can be programmed to open earlier or close later, according to wind and drift conditions. The valves are controlled by pneumatic (compressed air) systems that give instant response with higher line pressures and are more durable to extended heavy cycling situations, such as close tree spacing typical of Florida.

Of course, the valves have to be told what to do and that is done by individual zone controllers on the Roper Tree-See and a computer on the Smart-Spray.

The Sprayer wheels are also sending information to the processors so that one can have data on area sprayed, GPAs, material saved vs conventional systems. The Smart Spray even has a reset program for citrus that tells the sprayer not to spray when passing mature trees.

This gives operators that ability to work an entire grove while spraying only smaller trees and resets. A hand held console allows the operator to program the machine according to what is going to be sprayed. This console also stores information and gives data on coverage, efficiency, etc., that can be used for pesticide application records.

What does all this mean?

Imagine a grove with about 30% resets. A conventional sprayer would be spraying the entire property with all of its nozzles on, except when the operator gets to the end of the row (if he remembers to turn them off or disconnect the PTO).

One of these Tree-See/Tree-Sense/Smart-Spray machines would detect the open spaces and absence of full size trees and only open the nozzles necessary to cover the resets, and not spray in the open spaces. Estimated savings: 30 to 40% -- You figure the dollars saved. The rest of us will benefit from the reduced air pollution.

There are dramatic savings in spray materials to be realized on young groves as well as new plantings. The trees occupy a fraction of the air space in the rows and these imaging systems can produce savings of up to 70% over conventional blowers in these situations.

Of course, as the trees grow, they begin to fill the empty spaces and the savings become less dramatic. However, in most mature groves, there are always empty spaces, resets and the general non-uniformity of the canopies, where savings can be realized with these "intelligent sprayers".

My direct experience has been with Durand Wayland's Smart Sprayers in two different tropical fruit operations, where I have found them to be more than worth the extra initial cost and, despite my initial fears, extremely dependable.

Down time has been minimal, considering the complexity of the system and parts availability and technical support is very good. Both growers have used the machines for over two years and practically on a daily basis in tropical conditions, mainly on Mangoes , Avocados and some citrus.

The actual savings have ranged from 60% in young groves (1 year old mangoes) to 18% in topped and hedged 5 year mangoes. Avocados have reported ranges of 15 to 30% in mature groves. Citrus (Limes) has varied between 15 and 35% - depending on the amount of resets in the field.

The manufacturers publish charts showing how the savings using these systems can return their cost in either one year or two, depending on the total amount of acres sprayed and based on average chemical reductions of 30%. The best way to calculate this is to use your own figures and consider that the costs of these systems add an average of 15,000.00 dollars to the cost of a full size blower (500 to 1000 gallons).

So, in essence, your exercise should go something like this:

Number of Acres Sprayed X Chemical Cost per Acre X .2 = Savings

And I put a multiplier of .2 to represent 20% and not 30% in savings, just to be conservative. To adapt this calculation to your actual situation you can use the following multipliers: New Plantings: .55 (55%) Young Trees: .45 (45%) Mature Trees: .15 (15%) Average: .20 (20%)

So if you spray 500 acres of young trees at 100 dollars per acre, your savings would be: 500 x 100 = 50,000.00 x .45 = 22,500.00

As you can see, these systems could produce important savings for your operation. In addition, the Roper system has been adapted to dry fertilizer spreaders, specifically for treating young trees and accurate placement. The advantage over conventional wheel driven systems is that it does not get out of "sync" with the plantings as it places the dose of material where the sensor has actually seen the target area.

These systems are also applied to herbicide applicators mainly to work with the outboard nozzle, which they will shut off when the sensor detects a tree or planting that should not be sprayed. Both the fertilizer applicator and herbicide systems are considerably less expensive and operate usually with only one sensor and can run in the $2000.00 range.

For additional information regarding specific systems and retro-fitting, contact:

AgTech Crop Sprayers
800-704-4292

Roper Growers Co-operative
800-872-5032

Durand Wayland Inc
800-241-2308

Chemical Containers Inc
800-346-7867