Much has been said and written about last year’s phenomenal peanut yields — a U.S. record-breaking average of more than 2 tons per acre.
Obvious factors contributing to such an astounding production include improved varieties and ideal weather conditions. A less obvious factor might be the increased use of GPS-based auto-guidance systems to harvest peanuts.
Some Alabama producers already are using the technology to enhance their yields and others are seeing the benefits as proven through research conducted at Auburn University.
Brenda Ortiz, Extension agronomist and assistant professor at the university, presented an update on the research at this year’s American Peanut & Research Education Society held in north Georgia.
The research is based on the premise that increasing the peanut digger efficiency by accurate placement over the target rows could minimize damaged pods and yield losses. Producers have traditionally relied solely on tractor operator skills to harvest peanuts. However, as peanut production has shifted to new growing regions in the Southeast U.S., growers face difficulties digging peanuts under conventional and new management schemes.
Current research is aimed at 1) determining the effect of row deviations from the target row on peanut yield and quality; and 2) determining the economic value of using auto-guidance systems to avoid tractor deviations during peanut harvest.
“During the last decade, the peanut production area in Alabama has expanded from the traditional region in the Southeast (with Coffee, Geneva, Henry and Houston counties providing 67 percent of the total production in 1999) to the central and southwestern part of the state, including Baldwin, Mobile and Monroe counties providing 18 percent of the total production in 2008. That means we have probably new peanut farmers and tractor operators with less experience harvesting peanuts,” says Ortiz.
New producers, inexperienced operators
The expansion towards non-traditional peanut production environments, in addition to the increased number of new producers, has partly influenced producers’ decisions to adopt new technologies such as GPS-based auto-guidance systems to improve field operations, management practices and ultimately, profitability.
“Experienced and new farmers face these two scenarios: a complete canopy cover at the time of digging, which makes it difficult for the tractor driver to properly find the target row, and rolling terrains in some fields that add even more complexity to the situation. We believe that if the deviation of the planter and the digger are more frequent under this scenario, then yield losses also could be higher. Also, the time required for digging might increase,” says Ortiz.
Before the introduction of GPS-based auto-guidance systems, peanut producers relied on skilled tractor operators to plant and then accurately harvest peanuts. However, inexperienced tractor operators — which is common today with the scarcity of labor — or producers farming rolling terrain can find it difficult to keep the peanut digger positioned over the rows.
The recent adoption of twin-row planters has increased the adoption of GPS-based auto-guidance systems throughout the Southeast.
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“Without an auto-guidance system, a tractor operator can find it difficult to center the equipment on the target rows because the canopy covers almost the entire ground, making the rows less visible at harvest.
“In addition, new peanut varieties with more disease tolerance are harder to dig even for experienced machine operators, because rank peanut vines remain green even at maturity. The green vines make it difficult for an operator to stay immediately over the row and invert peanuts properly.”
GPS-based auto-guidance on tractors might help producers when adopting these new management practices. It allows the operator to place the tractor to within one inch of the desired center line. When used for deep tillage, planting, spraying and digging, auto-guidance systems have the potential of eliminating producer concerns about properly centering the equipment in a completely closed canopy, especially when crops are planted using contour farming.
A two-year AU research study was conducted in the traditional peanut producing area of Alabama to evaluate the potential of adopting GPS-based auto-guidance systems for peanut production.
Yield differences that occurred during peanut digging as a result of deviation of the target row (3.5 and 7 inches off) with respect to exactly over the row (aided by RTK guidance) were evaluated in both conservation tillage and conventional tillage plantings.
“Studies conducted in Alabama under straight-row conditions showed that yield losses increase as the digger deviates from the target row. Net returns also decrease as the digger deviates from the target row. Our data indicates that row deviations of approximate 1 inch might result in yield losses of 166 pounds per acre,” according to Ortiz.
Peanut yields on conventional-tillage were 600 pounds per acre higher than strip-tillage with twin rows yielding more than 472 pounds per acre over single rows.
“We looked at the yield differences between RTK (real time kinematic) auto-guidance and manual guidance at two farmer fields in Georgia and three fields in Alabama. Significant differences between both guidance systems were observed on the two fields in Georgia, with higher yields from the RTK auto-guidance systems.
“When we looked at net returns, between both systems — RTK auto-guidance and manual guidance — higher net returns were observed on the RTK auto-guidance treatments. Higher yields also were observed from using the RTK auto-guidance treatment.
“In one field the farmer perceived net returns of $23,000 for using RTK auto-guidance systems.
In summary, says Ortiz, higher yields and net returns resulted from using the auto-guidance system to harvest peanuts.
“Overall, yields were higher for the conventional tillage and twin-row pattern treatments compared to the other treatments. The use of an auto-guidance system will allow growers to capitalize on the increases in yield potential by implementing changes in tillage and row patterns as those evaluated in this study.”
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