Wednesday, November 15, 2017

Harvesting Pawnee pecans

    We've been working our way through harvest picking up nuts in a various research plots. Last week we harvested Pawnee (photo at right) and I was pleased to see that summer shaking really paid off in terms of nut quality this Fall. This year's Pawnee nuts are some of the best we've every raised.
    Pawnee has become a popular cultivar in northern pecan states because it ripens early and it produces large, thin-shelled nuts. With a good scab control program and crop load management, Pawnee can be a reliable income producer.  
     However, we have experienced one problem in growing Pawnee that is rarely if ever mentioned--Pawnee nuts do not fair so well when harvested mechanically.


    The shells of Pawnee nuts are so thin that they often get cracked during harvest operations. I collected a few nuts from the cleaning table to show you what I mean. The majority of Pawnee nuts come through harvest fully intact (first 3 nuts in top row, photo above). Many nuts get cracked but the shell still covers the nut meat (top right nut, above). However, about 5% of the Pawnee nuts that come across the inspection table are cracked open, exposing the nut meat inside (nuts in bottom row, above).  Sellable pecans must have intact shells to protect nut meats from contamination. When we sort our Pawnee nuts, any nuts with exposed kernel are thrown off the table.
   Although consumers prefer nuts with paper-thin shells, they also demand a clean wholesome product. I have come to the realization that pecan cultivars that produce nuts with greater than 56% kernel will suffer signicant nut losses due to mechanical harvest using current equipment.  This observation is something I'll keep in mind when evaluating the nuts produced in our breeding program.

Thursday, November 9, 2017

A mild freeze and pecan leaf fall

Kanza pecans, 2 Nov. 2017

   I don't think I've ever seem pecan trees hold on to their leaves like this year. During most years, we get a hard freeze in early November that causes pecan leaves to drop off the tree in just a few hours. Not this year.
    Temperatures dropped to 27 degrees (F) on a couple of occasions in late October which froze leaf blades but did not kill leaf rachii (photo above). The result of this weather pattern has been that shucks have opened up but the leaves have remained in place (even with frost burned leaflets).
    We have harvested several pecan cultivars this week but have found that the semi-green leaves that cover the ground after tree shaking has made harvest by machine a lot less efficient. It seems that the machine is having a hard time digging out pecans from the still leathery leaves.  After a hard freeze (less than 26 F), leaves turn crispy dry and are ground up by the harvester.
    In time, our harvest problems will pass as colder temperatures are surely on the way. However, a second trip over the orchard with the harvester later this fall will yield far more nuts than in previous years.  

Wednesday, November 8, 2017

Who's eating my pecans?

   While harvesting this year's pecan crop, I spotted a few nuts that had their shells broken open by one of the many critters that feed on pecans (photo at right). By just looking at the damaged nuts, I can tell the which pest caused the damage.
    A woodpecker caused the deep narrow hole in the nut labeled "A".  With their sharp, narrow bill, woodpeckers punch a hole through the shell  and feed on the kernel inside.  Woodpeckers carry off small native pecans and cache them in tree voids for later consumption. Since they can't carry off large, thin-shelled nuts they simply take a quick bite before getting back to work stealing native pecans.
   Mice will climb up into trees and start gnawing into pecans as soon as the shucks split open. You can always spot a mouse damaged nut by the neat round hole they chew into the side of the shell (pecan "B").  They usually make the hole just large enough to poke their head into the shell and clean out every morsel of pecan kernel.
    A nut with a large irregular cracked hole was attached by a bluejay or crow (pecan "C"). These birds have large beaks that they use to pound open the shell. Often the nuts are broken in several pieces but they always eat the entire nut kernel inside.
    Wildlife can eat a significant proportion of a pecan crop so its always important to harvest as quickly as possible. The list of critters that eat pecans include not only the three pests described above but also includes squirrels, raccoons, deer, coyotes and turkeys.   

Monday, October 30, 2017

The 2017 harvest begins


    After a couple of hard frosts over the weekend, we began harvesting pecans today (photo above). Although the shucks of all our cultivars have split, only the earliest ripening pecans were dry enough to harvest. Pecans, like all grain crops, should be less than 12% moisture at harvest so that they can be stored without danger of molding. Pecans harvested at a higher moisture content must be dried with forced air to prevent spoilage (again just like grain crops).
   Today we harvested Osage, Jayhawk, Shepherd, Norton, Henning, Grotjan, Canton, and USDA 64-11-17. The tree being harvested in the photo above is Osage. All of the cultivars harvested today split their shucks a month ago in late September. The first day of harvest is also a good day to work out potential problems with our harvesting equipment. Thankfully, everything ran smoothly!