A Weighty Decision

Dig at optimum maturity with the aid of a profile board.

• By Amanda Huber •

mesocarp colorDetermining when to dig is always tough. The maturity profile board, developed in 1981 by E.J. Williams and J.S. Drexler, ushered in a new era of determining how close to ready a crop was without special equipment and the destruction of the pods.

Auburn University assistant Extension professor Kris Balkcom says, “The peanut maturity profile board is a tool that helps you get an average look at what kind of crop has been set and helps determine optimum digging.”

The profile board works because as peanuts mature, the mesocarp color changes from white to yellow, orange, brown and then black. Although kernels in pods with an orange mesocarp are mature enough to be considered sound mature kernels, they continue to increase in both yield and grade by adding weight as they grow.

To use the profile board, producers expose the mesocarp using a pressure washer.

“A pressure washer in the range of 1200 to 1600 psi is sufficient,” Balkcom says. “You don’t need a bigger one. The smaller ones do a good job and keep from busting up the pods, including the immature ones.”

Start With A Good Sample

The key to getting an accurate reading on the profile board depends on getting a good sample.

“Pluck up a small bunch of peanuts from different locations across the field. Pick plants that are uniform and free of disease. Disease would affect the sample,” he says.

“Look at the pods and make sure they don’t show symptoms of disease. There could be pod rot or underneath white mold. You want to look at those pods to make sure they are good and healthy and that will give you a good sample reading.”

Balkcom also says to look at the foliage and the condition of the vines and stems.

“You want to see that the plants are in good shape and will hold onto those pods.”

When you have all the samples gathered, pick off all the harvestable pods from the plant, including fully formed pods and immatures.

“Pick off all the pods that would go into the combine basket if being picked. Continue until you have got a good uniform sample of about 200 pods. That’s the sample size you need. Like soil sampling, the goal is to get a good average,” he says.

Blast Hull To Show Mesocarp

7 days to maturityAt that point, the sample goes into a wire mesh basket, and using the pressure washer, the outer layer is blasted off.

“Do not place the nozzle too close to the pods because it could disintegrate the more immature pods. As you begin to wash and spray the outer hull and expose the mesocarp, you can see the different color underneath.”

Once you are satisfied that the hulls of the sample have been separated and the mesocarp underneath exposed, the sample is ready for grouping into colors.

“On the board, pods are placed light to dark with lighter ones being less mature and darker ones more mature.”

Shell Pods To Expose Kernel

Once the pods are separated by color, Balkcom says some peanuts grouped in the darker area should be shelled so you can see what is happening with the kernel.

shelled nuts“Pods that are completely mature have a nearly black or black hull and the seed coat is tan or copper colored.

Those pods would be placed in the three days to harvest category.

“The next group would have a seed coat that is a lighter color, but with dark oil spots formed on the surface as the peanut gets closer to maturity. The oil content increases in the kernel and comes to the surface. When you see the darkened oil spots, that generally means it is about seven days away from maturity. At 10 days, oil spots are not as distinctive as they are at seven days.”

Balkcom says many of the hulls will be dark, which is why shelling them is necessary.

“You need to take a look at what’s going on inside and look for those oil spots as a tell-tale sign of maturity progress.”

Take Two Samples For Certainty

Other scenarios producers may see are where one kernel has the copper-tinged seed coat but the other has the oil spots.

“With one fully mature and the other needing a few days to bring it along, we would put that in the three- to five-day range,” he says.

When you end up with two distinct groups on the board, it is likely because there was a drought in the mid-season.

This type arrangement presents some challenges, Balkcom says. “The risk in waiting on the crop to mature further is losing those pods that are already mature.”

To get a more accurate picture of digging date, producers should pull samples and perform the profile maturity board check at least twice. The first time should be when it is estimated that the crop is about 10 days from digging. The second check would be when the first sample said to dig.

“Two checks will give you a better chance to get the top dollar for your crop,” Balkcom says. “It’s very important when you think about selling by the ton on the grade and you get more money per point. It adds up.”

Maturity profile boards are available at county Extension offices, buying points or product sales representatives.

Performing A Maturity Profile Board Check:

• The sample must be a good representation of the field to get an accurate recommendation for digging.

• Pull a field sample and check it against the profile maturity board at least twice. Two checks offer more assurance that you are on target for a proper digging date.

NCSU Offers Updated Peanut Maturity Board

maturity boardNorth Carolina State University Cooperative Extension recently released an updated maturity profile board for Viriginia market type peanuts. It will be available through Extension offices.

NCSU Extension peanut specialist David Jordan says, “We included some images of things you might see in your crop on the profile board. The goal is to make it a better management tool and to help identify potential problems to avoid in the field.”

For many years, the North Carolina Peanut Growers Association has supported NCSU research and Extension efforts that have contributed to the information provided on the peanut profile board.