Research conducted in Georgia this past year shows that on average, growers could see a 300 to 400-pound-per-acre increase with twin-row peanuts compared to single-rows. But 2005 proved to be an especially favorable year for twin-rows, says Eddie McGriff, Coffee County Extension coordinator.

Research conducted at the Troy Aldridge farm in 2005 showed twin-rows had an average yield increase of 691 pounds per acre over single-rows, says McGriff. Twin- rows averaged a 71 grade compared to a 69 grade for the single-rows, with the two points meaning an extra $20 per acre for the twin-rows.

The yield and grade advantage at loan price ($355 per ton) of twin-rows compared to single-rows was $143 per acre, with the additional cost of an in-furrow insecticide deducted. In addition, there was almost three times the amount of tomato spotted wilt virus in single-rows (13 percent) as in twin-rows (5 percent). Twin-rows also were slightly earlier in maturity compared to single-rows this past year due to a higher percentage of tap root peanuts compared to limb crop peanuts, with single-rows having a higher percentage of limb crop peanuts, according to McGriff.

Producers, he says, need to consider switching to twin-rows if they plan to continue growing peanuts as a primary crop. “It would not have taken many acres to pay for a twin-row planter this year, and how many pieces of equipment pay for themselves in one year?”

When growers consider that a new six-row Monosem vacuum planter costs between $35,000 to $37,000 (a refurbished six-row Monosem vacuum planter with one year’s warranty runs between $26,000-$27,000), the additional twin-row money this past year from 252 acres (or 185 acres for a refurbished planter) would have paid for a new planter, says McGriff. An eight-row Monosem costs about $45,000 to $ 48,000.

There are other twin-row planters, he says, including Cole, Burch and Covington. “These are cheaper but they are not vacuum planters and do not plant as fast as a vacuum planter. Burch can be bought new and designed for the number of rows needed. Covington Planter Company has both the Covington and Cole planters. Covington has only two-row Covington planters in stock but will make a four-row planter on special order. Cole planters are mostly for small acreage.”

Another option, says McGriff, would be renting a Monosem planter. “We have talked to a couple of farmers who are interested in renting a planter, and there may be an opportunity of renting. Growers can let us know if they’re interested. Other options for planting in twin-rows include mounting an additional toolbar on an existing planter or double planting. Double planting is not a viable option for most growers and probably should be considered only by growers wanting to try twin-rows on a limited acreage.”

In 2005, seven peanut varieties were planted in the Coffee/Atkinson Counties Variety Trial. There were four mid-season varieties (Georgia Green, AP-3, Carver and AT-3081R) and three late-season varieties (C-99R, Georgia-02C and Georgia-01R). Each variety was replicated four times in both single and twin-rows.

Each variety was planted at three seed per foot of row in twin-row patterns (a total of six seed per foot of row) and six seed per foot of row in the single-row patterns. Five pounds per acre of Thimet 20G was applied in-furrow of the single-rows and 3.5 pounds per acre of Thimet 20G was applied in-furrow of each twin-row (total of 7 pounds per acre).

The variety trial was strip-tilled and planted under irrigation. Maturity date was determined by the hull-scrape method. The mid-season varieties were dug on Oct. 3 but due to rain and overcast conditions, they were not harvested until Oct. 14. Late-season varieties were dug on Oct. 24 and harvested on Oct. 27. McGriff recommends comparing only mid-season varieties to other mid-season varieties and late-season varieties to other late-season varieties due to the delayed harvest. The grower’s normal management practices were used on all varieties and row patterns.

The trial was planted on May 23 and by July 3 the twin-rows had completely lapped whereas the single-rows were still three weeks from lapping, says McGriff. Quicker ground cover is one of the reasons twin-rows outperform single-rows. Research has shown that quicker ground cover aids in weed control, lowers soil temperatures, conserves moisture, and helps reduce tomato spotted wilt virus.

Twin-row peanuts performed significantly better than single-rows this past year, notes MGriff. Typically, growers have seen a 300 to 400-pound per acre boost from twin-rows compared to single-rows. But in 2005, the increase was closer to 700 pounds per acre.

“We had ideal rainfall this past year when the peanuts were setting their taproot crop. Twin-row peanuts set two taproot crops — one for each row — compared to the one taproot for the single rows.”

Single-row peanuts continued to try and set a large limb crop, but seven weeks of drought beginning in August did not allow for the limb crop to completely fill out, he says. The drought’s effect on the limb crop hurt both yield and grade, but because limb-crop peanuts made up a higher percentage of the peanuts in single-rows (twin-rows had a higher percentage of taproot peanuts), single-rows suffered more.

The large limb crop this past year contributed to low grades, says McGriff. “Typically, when we set a large limb crop, grades will be slightly lower — more young peanuts will lead to more immature kernels. When we combine a large limb crop with drought in August and September, there were more immature peanuts that were not able to fill out.”

Immature or kernels that were not filled out often were classified as other kernels, he adds, and the grades were off three to five points much of the season throughout Georgia. “The grades in the official variety trials were in the high 60s or low 70s when they are normally in the mid 70s. Also, some varieties, such as AP-3, have a thicker hull so this also may have contributed to lower grades.”

Some growers are concerned that they may have dug too early, says McGriff. “If your grades started off in the high 60s or low 70s, you probably started digging at about the right time. It is important to remember that profit should be a grower’s No. 1 goal. Each grade point is worth approximately $5 per ton.

“For example, if growers had waited to increase their grades by three or four points, they could have improved their income by $22.50 to $30 per acre on 3,000 pounds per acre. At the same time, research has shown when mid-season varieties are dug 10 days late, yields were reduced by 16 percent. So, while growers may have picked up $22.50 to $30 per acre in grades, they could have lost as much as 480 pounds per acre on 3,000-pound peanuts or $85 per acre on yield by digging too late. While good grades are important and should be strived for, digging late can be devastating.”