Saturday, August 23, 2014

GPS Steering and Plot Work

Auto-steer has been around for a while in the more expensive tractors.  I remember the first time I saw someone making vegetable beds with a GPS system and auto-steer—WOW!!  Traditionally, a farm would have one guy—a Prima Donna usually—who was the Lister Driver (a lister is the shovel implement which makes beds)... and this guy was revered for being able to drive straight and with consistent guess rows. 

Guess Rows are the bane in row crops… a guess row is the space between implement passes… Let’s say you have an 8 row Lister, which means it has 9 identically shaped shovels spaced EXACTLY the same distance apart, and at exactly the same depth mounted on a perfectly level tool bar.  So those 8 rows are all the same.  Same height, and of course, all the same distance from peak of the row to the peak of the adjacent rows.  In our case with vegetables, that peak to peak distance is 42.0 inches. 

So you make a pass and you have 8 beautiful beds…you get to the other end of the field and then you get ready to drive back.  In the old days we used a marker.  The marker was a shank with a small shovel of some flavor which was set so that it was in the middle of the next pass with the tractor.  The idea being that you would drive over that line and everything would be straight and even.  And this is where the “Lister Driver” excelled… he could drive that line straight as an arrow, and be only an inch or two off.  And he was king.  Everything else hinged on his straight rows.  The cultivating, the spraying, harvesting all went much better when the rows were straight and even.

So our mystical Lister Driver would make his turn and then get lined up on the mark… usually requiring a couple of backups and pull forwards to get this 28 foot implement mounted on a 300 horse tractor exactly right.  The advent of GPS accuracy, brought about after President Clinton, (during lulls between sessions with Monica) signed the bill which removed the distortion from the navigation satellites and allows sub-inch precision with the right receivers.  So now most anyone can drive a lister, do a better job and be quicker.  Why? Because when you make your turns, you don’t have to line up adjacent to the previous pass, you can make a broader and easier turn, kick on the auto-steer when you are close and the machine takes over and puts you right where you want to be.
4 Little Devils Farming's 28 foot Lister completing
 a pass in an RD4AG field soon to be in Lettuce.  Take a
tape, every bed is 42.0 inches apart

Back when, the suggestion that you could list 28 feet, move over 112 feet, and have that pass end up being in the right spot, and I mean DEAD ON, was the dream at beer bashes and whiskey parties.  And today, most anyone can do it. But these systems work best at 3 mph plus and they are a 30-50 thousand dollar add on to the hydraulic systems on to a new or used tractor.  And they don’t really put them on small tractors like we use in research. A few years back Trimble decided to appease the Tulip growers in Holland, designing a system which would be accurate at the 2 kph (1.2 mph) speed they used when transplanting.

But those are still expensive ad ons—to do the plumbing into your existing tractors hydraulics was pushing 20 grand, plus another 10 for the GPS system.  For most of us, that would more than double the tractor value!  We have been working with our friends at Triangle Ag in Fort Benton, Montana on this for a while.  DeImna worked in research while getting her degree at University of Idaho, so she was sympathetic to our issues, and she made the error of not hanging up on me the first time I called…

With her help, we found a good used Trimble FMX GPS machine and then we bought the components to put Trimble’s gear based steering wheel auto steer system.  It still cost us 10 grand but we felt like this was a bargain for technology we needed as the precision required of us gets tighter and tighter each season.  We have been playing with this for the past couple months, and we are finally getting it dialed into where we want.  The first tries found the machine not sure which line it should be taking… we are doing passes of 5 or 6 or 7 feet at 1.5 mph when planting, and that takes different settings than 28 feet at 5mph… but as you can see from the photos from yesterday’s corn planting, we are getting the hang of it.  Our guess rows are 41-42-43 inches, on a nominal 42, so things are good.  And this makes such a huge improvement in the other tasks later…  
Straight rows... Magical!  The angled dirt ridge is from a previous operation.
Those are Medjool Date palms in the back ground.

Our Excellent SRES Runabout Research Planter

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