Saturday, November 22, 2014

Kanza performance 2014

2014 Kanza crop
   If you have been following this blog for some time, you know that I have been documenting the yield and performance of a three acre block of Kanza trees. This year we harvested a good crop of nuts, averaging 1268 lbs/acre (see table below).  
     In looking over the records for this block of trees, it is interesting to see the impact of below-average rainfall on tree performance. During the years 2011, 2012, and the first half of 2013 the trees suffered from serious water shortages. Drought conditions impacted tree grow rate, nut weight, and yield. In 2013, mid-summer rains helped to increase nut size but yield had already been impacted by the previous season's drought. You see, each spring's pistillate flower production is largely determined by growing conditions during the nut filling period the previous summer. 

   

Cracked Kanza nuts, 2014
    In 2014 tree grow rate responded to better soil moisture conditions and total pecan yield increased. However, the dry spell we experienced in mid- summer decreased nut size and increased the number harvested stick-tights.    
    Over the years, we have progressively thinned this Kanza block as trees begin to crowd. The thinning plan for this orchard and our tree removal progress has been posted to this blog. When planted, this block of trees contained 144 trees spaced 30 feet by 30 feet. So far we have removed 17 trees but the thinning plan calls for the eventual removal of 72 trees in total (resulting in a 42 ft. x 42 ft. spacing). However, by taking a thin as needed approach to tree thinning,  we have maintained total block yield despite experiencing problems with drought.

Tuesday, November 18, 2014

Grafts survive cold snap

    When I woke up this morning the temperature outside had dropped to 6 degrees F (-14 C). For mid-November that's pretty darn cold. When I drove by some of my young pecan grafts today, I noticed some of the leaves were still frozen on the tree (photo at right). These leaves had frozen back on November 4th during our first hard freeze, but when leaves remain on the tree it indicates that those branches had not fully hardened off in preparation for winter before the cold weather hit. With the extreme cold this morning, did my young grafts suffer cold injury?


   To check for winter injury, I took my pocket knife out and cut into the main stem of the graft and peeled back the bark. Winter injury on pecan first appears as brown streaks in the  inner bark. The inner bark of this tree was healthy and green (photo a left). The two small, circular, brown spots you see on the inner bark are wounds caused by insects that feed on the stem last summer. 
    This young graft had several, small-diameter shoots at the top of the tree (see photo above). These shoots had developed in mid-summer as a result of a second flush of vegetative growth. This was also the portion of the tree that was still holding on to its frozen leaves.
    Were these shoots injured by the extreme cold? To check, I cut into the wood for look at the inner bark (photo at left). I found nice green inner bark. At this point in time, this Kanza graft looks in good shape.
   Early this year, I decided to top-work a few Jayhawk pecan trees to some new cultivars. When you graft such large trees, the scions grow extremely fast and tall. Vegetative growth can continue late into early-Fall and that new tender growth can be prone to winter injury. The photo at right is one of the top-worked trees I grafted last spring. The graft union is painted white and the scion grew a healthy five feet in height this past summer. Note that the branches below the graft have lost all their leaves while top of the new graft has leaves frozen in place. I needed to check this graft for cold injury.

   I cut into the stem of the new graft and peeled back the bark. The inner bark was still green and healthy (photo at left). No cold injury here.
  

Monday, November 17, 2014

Winter arrives in mid-November


    Last week we harvested a lot of pecans despite the below normal temperatures. Conditions were dry and the harvest machinery was working great. Unfortunately, 3 inches of snow fell yesterday and the grove was blanketed in white (photo above). It will take some time before the snow melts and the ground dries enough to resume harvest. In the mean time, we'll be in the barn running harvested nuts through the cleaner.  

Saturday, November 15, 2014

Kanza, stick-tights and crop load regulation

  Kanza has become a very popular pecan cultivar because no matter the weather, Kanza always seems to produce a quality kernel (photo at right). Over the past four years, I've been watching our Kanza trees closely and I think I've  discovered one of the ways these trees preserve kernel quality even when faced with stressful weather conditions.  It looks like Kanza trees self thin a portion of their nuts to ensure full kernel filling for the rest of the crop.

    We recently harvested a block of Kanza trees and had dumped a load of nuts into the pecan cleaner. When I looked at the nuts swept up by the harvester, I noticed a large number of stick-tights. The photo at left shows an example of field run Kanza nuts before cleaning. There were plenty of good Kanza nuts mixed in with a few sticks, leaves, and dirt clods. But what stands out are the nuts trapped in blackened shucks.
   It turns out that about 12% of Kanza nuts collected by the harvester this year were stick-tights. Just looking at the photo it seems like the percentage should be higher but a nut stuck in the shuck takes up a lot more space than a nut out of the shuck. 
   I separated out several of the stick-tight pecans, peeled the shuck off, and cracked open the nuts. In every case, I found a brown, paper-thin kernel inside. It looks like each of these stick-tight pecans stopped kernel development at the water stage leaving only the seed coat inside the shell.
   The question becomes--"Why did these nuts stop developing during the water stage?".  During the summer of 2014, we experienced an extended period of dry weather that started during the final stages of nut sizing and continued until late August. In addition, our Kanza trees had set an above-average crop. Most pecan cultivars react to these circumstances by aborting a portion of their crop in what is commonly known as a water stage drop. Nuts dropped in mid-summer often disappear by harvest as they decompose in the ground cover.
   Kanza is different. A Kanza tree stressed by drought and crop load turns off the nut development process during water stage for a portion of the crop but those nuts remain on the tree until harvest. 
   The good news is that Kanza seems to do an excellent job of regulating its crop load to ensure that fully ripe nuts are well filled. The bad news is that cleaning the Kanza crop following a mid summer drought will take a little more time to remove numerous stick-tights.