Electronically-Controlled Tree-Fertilizing Trailer Outperforms Eight Human Workers

Electronically-Controlled Tree-Fertilizing Trailer Outperforms Eight Human Workers WAGONS/TRAILERS Miscellaneous 25-4-4 When fertilizing plantation or nursery trees, you can broadcast or inject materials between the trees and hope the roots extend far enough to pick up the nutrients, or you can do what Randy Thompson does and apply fertilizer close to the trees where you know the roots can find it. Of course, putting fertilizer in just the right spot can be difficult and time consuming. Thompson, who raises fast-growing Paulownia trees, says most growers hire people to do the job. He built a machine to do it. "A crew of eight people, applying about 1/2 lb. of fertilizer per tree, can cover about 10 acres a day," he says, noting that for best results, Paulownia trees need fertilizer three times a year. Thompson knew he couldn't fertilize his trees by himself in a timely fashion, and he was reluctant to hire a crew to do it, so he went to work on a machine. Paulownia trees are planted in rows 12 ft. wide, spaced 12 ft. apart in rows. What he wanted to do was fertilize two rows of trees at once. He started with a single-axle dual-wheeled military surplus trailer - the kind used behind 2-1/2-ton trucks. He removed the truck-type ring hitch and added a clevis-style hitch so he could fasten it to the drawbar on his tractor. On the trailer, he mounted a stainless steel hopper-bottomed fertilizer mixer tank. He wanted to use stainless steel augers to distribute the fertilizer out each side of the tank, but found that a pair of augers would cost $3,000. After an extensive search, he found some at a feed store which had been special-ordered for a customer who later changed his mind. Each auger has its own hydraulic drive motor, so it can run independently of the other. That way, he can fertilize a tree on one side without dumping fertilizer out the other side. However, Thompson needed a way to turn the augers on and off. With the help of the Rural Development department at the Ag College, Tifton, Georgia, he found an electronic system that uses infrared sensors to "see" the trees and turn the augers on and off. "They helped me design the system and ordered the sensors and controllers for me," he says. "I'm not putting on a lot of fertilizer per tree, so the augers are only on for about .35 seconds per tree. I can run down between the rows at 4.5 mph, with the augers constantly clicking on and off," he says. "Obviously, there's no way I could go this speed if I had to control the augers manually." Thompson says one person can fertilize 4.5 acres an hour with his system. In an eight-hour workday, that's 36 acres, in contrast to the 10 acres of trees an eight-person crew can do in the same time. Except for the electronic technology, the trailer was relatively inexpensive. "I paid $425 for the trailer from a local salvage yard. It's built heavy enough to handle the load, and the 12-ply tires on it were in good shape," he says. He paid $125 for the tank. And his good fortune in finding the augers helped keep the cost down. The sensors and controllers, however, made it a bit more costly. Originally, he pulled the trailer behind a tractor with limited hydraulics, so he installed two hydraulic pumps on the trailer, too. "The pumps are still there, but I'm using a newer tractor on it, so now we can hook directly into hydraulic remotes," he says. He says the technology could be used for any widely spaced crops, such as in tree and shrub nurseries or in tree fruit, berry or nut production. Contact: FARM SHOW Followup, Randy Thompson, 8794 Denham Road, Sycamore, Ga. 31790 (ph 229 831-4795; E-mail: dianet@surfsouth.com).

To read the rest of this story, download this issue below or click here to register with your account number.