Thursday, October 20, 2016

Pecan maturation after shuck split

   The date a pecan cultivar splits its shuck is an important indicator of how well that cultivar is adapted to the climate at a particular location. However, pecan maturation does not stop at shuck split. A pecan does not become fully mature and achieve full flavor until the kernel dries down to under 12% moisture. To demonstrate how pecan kernels change as they dry, I harvested some Stuart and Kanza nuts (photo above). The Stuart nuts were loose in the shuck but the shuck had yet to split open. The nuts inside the Stuart shucks are still at their maximum moisture content. Kanza nuts split shuck 3 weeks ago and the nuts inside have begun to dry down.

    When I cracked open both cultivars I had lots of trouble producing full kernel halves (photo at right). Both kernels were tight against the shell so that when I  cracked the shell  I also broke the kernel. In handling both kernels, I could feel the moisture on my fingertips. The Stuart kernel was really wet, giving the kernel a sticky and rubbery feel. In contrast, the Kanza kernel was smooth but still slightly rubbery.
   The obvious difference between these two cultivars was kernel color and appearance. The high moisture Stuart nut was white and covered in brown fuzz. The shell packing material in the dorsal groves was a sticky mess. The Kanza kernel appeared to have normal color and the packing material fell free of the kernel.
    Looking at these two pecan cultivars gives us a pretty good idea of how pecan kernels mature after shuck-split. The drying process helps the kernel separate from the shell and all internal packing material. The outside of the kernel dries to a golden brown color. Full pecan flavor is achieved only when kernels dry down to less than 12% moisture.

Tuesday, October 18, 2016

Fall fertilzation

    Its finally dried up enough to allow us to make our regular Fall application of nitrogen fertilizer. The weather forecast calls for a 40% chance of very light showers tomorrow. So today, we spread 100 pounds of urea fertilizer over the entire orchard floor. One hundred pounds of urea equals 46 pounds of actual nitrogen. I'm hoping for just enough rain (or even a heavy dew) to help move the applied nitrogen into the soil profile.
   In the past, many growers have asked how I handle the fertilization of young trees. As the photo above shows, my approach has been to use conventional fertilizer spreading equipment to cover the entire orchard floor with fertilizer. Even though the trees look small on top, these 4 to 6 inch diameter trees have root systems that extend outwards twice the height of the tree. By spreading the fertilizer over the entire grove, I hope to encourage additional lateral root growth to help the tree be even more efficient in mining the soil for water and nutrients.
    Of course, the added nitrogen will also stimulate the ground cover to grow like crazy. But the way I look it, I'm actually growing a green manure crop right in the orchard. Every time I mow the ground cover, I'm adding tons of organic matter back to the soil. Soil organic matter helps build soil structure, improves water availability, and makes micro-nutrients (including zinc) more available to the tree.

Monday, October 17, 2016

Pecan cultivars ripening in mid-October

Giles, 17 Oct. 2106
    Last week the Neosho River flooded our pecan grove. As soon a the flood receded, we received a day-long rain storm. Water and mud was everywhere. Today was the first day I could get out into the field to check on nut development. Since its been two weeks since I last checked for cultivars with shuck split, I found many pecan cultivars had ripened since early October. Photos of those cultivars ripening in mid-October are at right and below.
    Note that Giles, Chetopa, Maramec, Caddo, and Dooley have scab lesions on their shucks. Scab has reduced nut size and prevented normal shuck-split of Dooley especially. Greenriver, Lakota, Oswego,  and Oconee are scab free.
Chetopa, 17 Oct. 2106
Greenriver, 17 Oct. 2016

Lakota, 17 Oct. 2106
Oswego, 17 Oct. 2106
Maramec, 17 Oct. 2016

Caddo, 17 Oct. 2016

Dooley, 17 Oct. 2016
Oconee, 17 Oct. 2016

Wednesday, October 12, 2016

Hark has a thick shuck

   Between the flood earlier this week and a soaking rain today, its been difficult to get out to the Pecan Experiment Field to check on pecan ripening. However, I was able to collect some nut samples from trees on my farm. When I collect samples, I like to pull nuts right out of split shucks to ensure that I get the right nuts in each sample bag. While collecting samples, I was surprised to find Hark has an extremely thick shuck (photo at right).

  But Hark is not the only pecan cultivar with this kind of thick shuck. I also collected nuts from Kanza and Yates 68 and found thick shucks covering both cultivars (photos at left).

    All of three of these cultivars (Hark, Kanza, and Yates 68) have a common parent--Major. The photo at right shows Major pecan also surrounded by a thick shuck. Close inspection of these four cultivars reveals other common cultivar characteristics. The nuts appear more rounded than many pecan cultivars and the outside of the shells are dotted with fine black speckles. When these thick shucks split, they do do not pull back away from the nut. This results in nuts being firmly held in the tree until a hard freeze kills the shuck and the tree is given a good hard shake.