Fall flooding delays fall fertilizer application to pecan groves

    In early October, I was trying to decide when to make my annual fall application of fertilizer to my pecan grove. At the time, daytime temperatures were still reaching the low 80's and the soil was dry. The combination of dry ground and hot temperatures is a sure way to lose soil applied urea (nitrogen fertilizer) to volatilization. So I waited for better weather conditions.
   It is now mid-October and the weather has turned wet and cool. Good conditions for fertilizing except for one thing. We've had a little too much rain and the Neosho River has spilled out of its banks (photo above). It is by no means a major flood. Portions of many pecan groves have anywhere from a few inches to a foot of water while other areas are just water soaked. 
    I am glad I waited to fertilize this Fall. If I had rushed to get the fertilizer on earlier this month, all my fertilizer dollars would have washed down the river. Now, I'll need to wait until the ground firms up before running a spreader over the grove. I definitely don't want to cut ruts in the orchard floor by dragging a fertilizer buggy over water-soaked soil.  
   Fall fertilization is an important part of my normal pecan management program. Applying fertilizer both Fall and Spring have helped to reduce alternate bearing in my grove. I'll be sure to post when I make this Fall's application including types of fertilizer and quantity applied.

Why is the date of shuck split important for pecans?

Yates 68, 5 Oct. 2018

   Every fall I have spent a lot of time in a hydraulic lift inspecting pecan cultivars for their date of shuck opening. Over the years I've created a photographic record of this important event for dozens of cultivars. Just today, I noted that the cultivar Yates 68 had just split open (photo at right).
    But why is nut maturity date such an important cultivar characteristic? In northern pecan areas, only cultivars that split shuck before the average date of first fall freeze should be grown. Too often, I have come across folks in the Midwest that plant pecan cultivars advertised in flashy nurseries catalogs that never reveal that a cultivar requires a much longer growing season to ripen their nuts. It is only after 15 years of tree growth that they discover their tree only produces black stick-tights every fall. (Desirable and Western are two prime examples of cultivars not adapted to northern pecan areas).

KT255, 24 Sept. 2018

   Now that I've retired from Kansas State, my focus has shifted from taking notes on established cultivars to recording maturity dates for the trees in the breeding project. In breeding pecans for our northern area, maturity date is of prime importance. And we have found some early ripening clones. KT255 and KT307 both ripened by Sept. 24th this year. That's really not surprising since both of the trees are the results of a cross between Pawnee and Greenriver. In addition both clones have good nut size, high percent kernel and are not prone to pecan scab infections.

 Please Note.  These clones are still under test and I am not in the position to supply scions at this time. When the time comes for a new cultivar release, I'll announce it on the blog.

KT307, 24 Sept. 2018

   

When is shuck split?

   While looking over trees in my orchard, I came across a young tree grafted to USDA 64-4-2. This is the third year after grafting and this tree was already setting on nuts. So I pulled down some lower limbs in the hopes of determining a shuck split date for this clone. However, I found two clusters in very different ripening stages. One cluster was fully open and appeared to be well on the way to shuck drying and nut release (photo above). Another cluster just one foot away on the same trees had not yet split shuck. Now, I was curious. Which cluster is more typical for the clone USDA 64-4-2?

USDA 64-4-2 not split yet

   I drove down to the old experiment station to check on the development of this clone on a more mature tree. On this tree, the shucks had yet to open (photo at left). I used my pocket knife to peel off the shuck and found that USDA 64-4-2 is very close to popping open. Last year this clone ripened just 2 days after Kanza. This year it will probably be closer to 4 days after Kanza.
   My observations on USDA 64-4-2 this fall confirms my long held belief pecan trees need to gain a little maturity before their true phenological characteristics become consistent and typical for that cultivar.

Pecan cultivars ripening by October 1

Kanza, 1 October 2018

    On the first day of October I found three cultivars on my farm with split shucks. The first cultivar I checked was Kanza (photo at right). When Kanza splits shuck, the green shucks just barely pull open. Kanza will remain held in these green and split shucks until a hard freeze kills the all green tissues. Once the shucks are killed, Kanza finally opens up fully and the nut can be easily shaken free.

Hark, 1 October 2018

     Hark was also ripe by October 1 (photo below, right). Hark mimics Kanza in how shucks barely split open then remain green and closely cupping the pecan. I first noticed this type of shuck opening years ago on the old northern pecan cultivar, Major. Both Kanza and Hark have Major parentage.

Jayhawk, 1 October 2018

    The final pecan I found ripe today was Jayhawk (photo below right). Jayhawk is a Giles seedling but has the advantage of pecan scab resistance. Unfortunately, Jayhawk produces pecans with mottled kernels which is the reason that I have only one Jayhawk tree on my farm.