Monday, October 31, 2016

Making plans to thin our Kanza block

    Readers of this blog may recall that we have a block of Kanza trees at the Pecan Experiment Field. In 2012, I drew up a tree thinning plan to remove a portion of the trees in this orchard to allow the remaining trees more room to grow. We took a progressive approach to thinning the orchard. We removed trees gradually, several each year, in areas where trees were beginning to crowd.
    This Fall, when I walked out to the Kanza orchard to check on tree spacing, I noticed that most areas that have not been thinned yet had limbs that were beginning to touch (photo at right).  Following the 2016 harvest season we will be taking out more trees, this time more trees than we had in previous years.

   I also checked areas in the Kanza block that had been thinned in previous years. Here I found the trees to be well spaced with plenty of light penetrating all portions of the canopy (photo at left). Eventually the entire block of Kanza trees will be thinned to this spacing (43 feet by 43 feet).  

Sunday, October 30, 2016

We need a good freeze to advance harvest

    Today, I walked out to my Kanza trees to check on the progress of the crop. Kanza shucks split open a month ago but I found most shucks still look like they did in late September. The split shucks are still green and still completely covering the nut inside (photo at right). A good hard freeze (26 F) would kill these green shucks, cause nuts to open up, and allow the pecan to finally dry.
   However, the forecast for the first week of November does not include any freezing temperatures.

   In the absence of a hard freeze, Kanza shucks will slowly start to dry and pull away from the nut (photo at left). This shuck drying process is painfully slow and occurs at varying rates both within a nut cluster and between clusters on the same tree.
    I like to wait until all the shucks are open and the nuts are fully dry before I start shaking Kanza. By waiting, I can shake once and get the entire crop on the ground at one time.

Monday, October 24, 2016

Testing out our harvest equipment

    Last summer we made some improvements to our harvesting equipment. To test how those mechanical modifications would hold up during harvest, I decided to shake some early maturing cultivars that had already dropped a large portion of their crop on the ground (photo at right).  We started with Colby trees today, and will move on to Osage and Canton tomorrow.  

    My main concern was to make sure the harvester would pick pecans the way we designed the machine (photo above). As many growers have seen during field days, we have modified our 8090 Nuthustler pecan harvester by making major changes to the drive line, nut elevator system, cross auger, and cleaning chamber. We even added a sweeper wheel to the harvester. This year we replaced the conveyor chain inside the machine. Rather than use the webbed chain as provided by the manufacturer, we inserted what is known as welded selvage belting in its place. We are hoping the selvage belt will last longer than the original chain and help sift out some of the dirt picked up by the harvester.

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.

Friday, October 7, 2016

Early October flood on the Neosho

   This week, parts of SE Kansas received over 12 inches of rain in a 3 day period. The Neosho quickly filled and has now spilled over it banks, flooding both the Pecan Experiment Field and surrounding native groves (photo above). The National Weather Service is predicting only a moderate flooding event that should last about three and a half days. Fortunately, we had not yet made our regular Fall fertilizer application. If we had spread nitrogen on the grove earlier this week, it would have ended up down in Grand Lake instead of helping our trees. After the flood waters recede and the orchard floor dries up, I'll be checking the weather forecast closely to choose the best time to spread some fertilizer later this month.

Tuesday, October 4, 2016

Pecan cultivars that ripened in early October

Major, 4 Oct 2016
    I was back out in the orchard looking for more cultivars with split shucks. Today, I found just three. Major is one of our standard northern pecan cultivars and a cultivar that has been around since 1908. Jayhawk is a seedling of Giles and Yates 68 looks to be a hybrid of Major and Posey.
   The shucks of a Major nut split along the suture lines but hardly open up  (photo at right). It will take a hard freeze to kill the green shucks before Major nuts are released from the tree.
Jayhawk, 4 Oct 2016

    Jayhawk and Yates both yield well but their kernels have major defects. Jayhawk kernels are often mottled with light brown spots over the straw-colored nut meats. Yates 68 kernels turn dark quickly after harvest in a fashion similar to Posey.
Yates 68, 4 Oct 2016

Monday, October 3, 2016

A tree can produce too many pecans

     Precocious and Prolific--Two words that pecan breeders like to throw around in describing their new pecan cultivars. A precocious pecan cultivar is one that starts to bear nuts at a young age. A prolific pecan cultivar produces a lot of pecans. The tree pictured at right is currently known as USDA 75-8-5. This clone has been touted as both precocious and prolific and you can see by the drooping limbs that this young tree is loaded down with nuts. However, excessive crops present their own set of problems. 

    In previous years, we have attempted summer tree shaking this cultivar as a method to reduce the excessive crop load. Unfortunately, summer shaking does not work well with this clone. In the photo above-left, note that the nut crop is held on the ends of long slender shoots. During a summer shake, these limbs just dance around and very few nuts are dislodged.

   The problem with over production becomes evident at harvest. For the photo above, I cut open three nuts pulled from the USDA 75-8-5 tree and compared them to three nuts harvested from a nearby Kanza tree. Both these cultivars ripened at about the same time but the cross-sections of the USDA 75-8-5 nuts reveals the impact excessive cropping has had on kernel fill. The USDA clone has thin kernels, lots of internal air pockets and the kernel was unable to fully compress the partition between kernel halves. But the real troubles will come this winter and next year. 75-8-5 has set itself up to be damaged by cold winter temperatures. If not damaged by cold, the tree will be unable to set a full crop of pistillate flowers next spring.
   The moral of this story is that heavy nut yield at a young age usually precedes a future of alternate bearing and cold injury. In testing new cultivars, I look for a tree to start bearing early but to build yield slowly always maintaining excellent kernel quality.