The productivity of fields in California's Imperial Valley is well known around the U.S. sugarbeet industry.
Average yield for the valley's 2011-harvested beet crop was 44.6 tons per acre; that of the 2012-harvested crop, a record 46.5 tons. Portions of individual fields have run well into the 70s-even above 80 tons on occasion-per acre. A long growing season (up to nine or 10 months), coupled with plenty of irrigation water, ample fertilization and mega heat units, combine to lay the groundwork for such high yield levels.
One of the challenges stemming from such yields, however, is the sheer size of sugarbeet roots, come harvest time. Individual roots-especially toward the latter part of the long Imperial Valley harvest-can commonly weigh 10 to 15 pounds, have a crown diameter between four to six inches, on average-and protrude several inches above the soil.
"These beets get so big that they hit the bottom of the strut with a 28-inch wheel," affirms Brawley grower Von Medearis. "Sometimes it's to the point where the digger just can't lift them, so they'll tend to pile up and fall out the front. Depending on how bad the situation is, there's potential to lose as much as 10 to 15 percent [of the roots] because you can't get them into the digger."
And that doesn't include any losses due to tail breakage, he adds.
As new sugarbeet varieties have been introduced into the Imperial Valley market, raising the tonnage bar even higher, Medearis began thinking about how to alleviate the problems with feeding those ever-larger roots into his beet digger. His conclusion was two-fold: (1) use 32-inch-diameter pinch wheels instead of the standard 28s, and (2) develop an "open-throat" strut configuration to provide more clearance in the middle.
Medearis' initial need-the 32-inch wheels-was first addressed a decade ago with the help of Kurt Piel of P & S Machine in Worland, Wyo., who manufactured a set of the larger-diameter wheels for the Imperial Valley grower. Medearis installed them on his WIC 826C harvester and used them up through the 2011 harvest season. In that year, Medearis sat down with John Lane of Stiff Equipment in Brawley.
Lane also had been mulling over the large-root-feeding issue and was open to input from Medearis and other area beet growers. Incorporating their suggestions, Lane produced AutoCAD designs for an open-throat setup, consulted again with Medearis and others, incorporated revisions-and then fabricated a prototype.
Medearis explains the difference:
"My old-style lifter struts had the two spindles mounted in the centerpiece. Then the pinch rows were fastened one on the left, one on the right.
"With this open throat, we now have an independent strut, an independent spindle-and hubs on the left and on the right. The paddle shaft comes through with its paddles, and the wheels lift the roots. With the open throat, we have plenty of clearance for those huge roots since we've eliminated that centerpiece. We're not striking the center of the beet prior to where the lifter wheels are able to grab it, pinch and lift it. That was the point where we had the problem before."
The strut system is held in place by a couple setscrews with a groove cut.
"If we do have bearing failure or a seal goes out, we just unscrew and pull them out; you don't have to replace the entire strut," Medearis explains. Adjustment is easy, too-which is particularly important in the Imperial Valley, where the drawn-out harvest season (April through late July or early August) results in significant differences in root size.
"Down here, we have to continually increase our pinch point" as the harvest progresses, due to the ever-increasing size of the beets, Medearis notes. During May, June and July, "we're changing our spacing at least every two to three weeks because the beets are constantly growing.
"We have a ratchet jack attached and loosen one side to move our row spacing. There's a reference line, and we've learned to open each side about a half inch each time. Button everything back up, and you're on your way. We can perform that whole operation in about 15-20 minutes."
Because the custom-built "Imperial strut" has a different hub, the original 32-inch wheels from P & S Machine did not interchange. In 2012, Medearis ran 28-inch wheels with the open-throat setup. But he and Stiff Equipment found that even with the open-throat, some roots were hitting the strut when operating in mega-high yield areas. "So for this year I had Stiff make me a set of 32-inch wheels for use with the Imperial struts, and the system is working great," he says.
Medearis, who custom digs for five other Imperial Valley sugarbeet growers in addition to his own acreage, says going with 32-inch pinch wheels on the Imperial struts this year did require a couple modifications.
"We had to move our paddle shaft back and also scoot back the apron shaft," he says, "just because the 32s are a little different `animal.' They lift the beets up in more of a gradual arc" than do the 28s.
Digger ground speed in the Imperial Valley is typically slower than elsewhere, Medearis adds, due to the sheer volume of beets being lifted.
"When you start getting into 50- or 60-ton beets-or higher-the harvester can only clean them so fast and get them onto the truck. So we have to slow down."
A true test of the open-throat system occurred during the 2012 harvest when Medearis was digging a field located next to a feedlot. A lot of manure had been dumped there through the years; plus, the grower probably over-fertilized.
He also ended up with an excellent plant stand. Parts of that field, Medearis affirms, ran more than 90 tons per acre.
"Those beets were monsters," he quips. "We were actually having some clearance problems, but we got through it. We wouldn't have, though, without the open throat." (That was the field, however, that convinced Medearis he had to go with 32-inch wheels, as they were hitting the struts with the 28s.)
All Imperial Valley beets are on 30-inch rows-a key to the feasibility of the open-throat strut.
"This probably wouldn't work out in 22s," Medearis says. "With our 30-inch row spacing, we're not worried about not having enough clearance between the hubs."
The open-throat struts are starting to attract more attention from other Imperial Valley growers. Medearis is aware of at least a half dozen operations utilizing them in 2013, and both he and Stiff Equipment's John Lane expect that number to grow in the future.
Source: www.sugarpub.com