Shuck split date and young pecan trees

    For northern pecan growers, the date of shuck split is one of the most important cultivar attributes we measure. Pecan cultivars that are well adapted for production in our area, split shucks at least one week before the average date of first fall freeze.  Late ripening cultivars usually suffer from poor kernel fill, fuzzy kernels, or "stick-tights" (pecans frozen in the shuck).
    In testing new cultivars, we are always anxious to discover the average date of shuck split. However, we have learned to be a little patient before coming to any conclusions about ripening time. In the photo above, you see two clusters of pecans. Both clusters were collected on the same day and from the same cultivar--Lakota. The cluster on the left was taken from a young tree (4 inches in diameter) while the one on the right was taken from a tree 28-years-old (12 inches DBH). In previous posts, I've talked about tree age and drought stress and how pecan trees grow to dominate the landscape. Here is another example of how young trees can differ from mature trees.

     Lakota pecans taken from the mature tree have been split for a good two weeks. Note the browning of the shuck near the tips and along the edges of each shuck quarter (pecan on right). In contrast, only one of the 5 nuts in the cluster cut from a young tree shows any signs of shuck split (pecan on left).

      Break off the shucks and you can see further evidence that pecans produced by young trees have delayed nut maturity. Full shell color has not yet developed (nut on left) as compared to the pecan collected from the mature tree (nut on right).
    It is no wonder why it takes so long to develop and test a new pecan cultivar.  Only trees that have grown large enough to "dominate the landscape" provide reliable nut size and maturity date information.

Harvesting intercrop soybeans

    Today we harvested the soybeans planted in our intercrop study. If you've been following this blog, you know that I've described the double-row intercrop system  in a previous post and also posted photos of this Spring's soybean planting. Like every field crop planted in SE Kansas this year, our soybean crop suffered from a lack of water. Yield was well below normal for full season beans. The final tally was 23 bushels/acre sold at $11.62/bu.

Pecan cultivar performance in the Bootheel

   Several years ago I started a cooperative pecan cultivar trial with Rick and Cindy Faulkner down in the Bootheel of Missouri. This fall, the young trees in the trial have started to bear a healthy crop of nuts. Pictured at right is a USDA clone 75-8-9 which bore a light crop and showed only a touch of scab.  Of all the cultivars under test at this location, Lakota, Kanza, Gardner and USDA 75-8-5 were the first cultivars to bear full crops with nuts hanging throughout the canopies.

    I visited the Bootheel in early October and found that Lakota was fully shucksplit (photo at left) at that time. That's great news for SE Missouri pecan growers.  It looks like scab-resistant Lakota will be well adapted to the SE Missouri growing season.

      Kanza is another scab-free cultivar that is doing well in the Bootheel (photo right). However, an increasing  problem facing pecan producers in the Mississippi Delta are the many species of kernel feeding plant bugs that attack pecan. In the photo at right, a leaf-footed bug is feeding on a Kanza nut even at shuck split.
    Plant geneticists have created genetically altered cotton and soybeans cultivars resistant to boll worm and pod worm. This has dramatically reduced the amount of pesticides applied to these crops in the Bootheel. However, with fewer sprays, plant bugs flourish and multiply in cotton and soybean fields. When these field crops mature, plant bugs look for alternative plant hosts on which to feed and pecan fits the bill.

Drought effects pecan nut shape

    Its interesting how our different cultivars react to drought stress in terms of nut shape. To document these changes in nut shape, I've collected nuts from several cultivars then arranged them in order of increasing drought stress.

  As drought stress increases, all pecan cultivars produce smaller nuts. However, there can be other changes as well. Note that the base of Giles and Maramec nuts get narrow as compared apex of the pecan. A nut with a strongly tapered base means that the kernels inside will also be strongly tapered. In comparison,  Kanza and Major nuts just seem to  shrink, turning into smaller, rounder pecans.  

     Kanza looses its distinctive "tear drop" shape as the prominent nut apex disappears in nuts made smaller by drought. In contrast, the "pinched" apex of Lakota can be recognized regardless of nut size or shape. Interestingly, I found Lakota nuts that had narrow bases and nuts that turned shorter and rounder all on the same tree.

    Because Major is a small nut to start with, this year's drought seems to have caused minimal changes in nut shape. Maramec, on the other hand, is a large pecan that suffers greatly from water stress. It is easy to see that Maramec nut size and shape are greatly impacted by lack of  soil moisture.

The Glory of Fall

    Pecan trees are not known for brilliant fall color. During normal years, pecan trees hold their green leaves up until the first killing freeze. When the freeze comes, pecan leaves turn brown and fall from the trees almost over night.  But this year's drought has changed everything. Pecan trees are shutting down early and putting on a beautiful display of golden leaves.

Time for Fall fertilization of native pecan groves

 
    Today we applied 100 lbs.of urea per acre (46 lbs N/Ac) to our pecan grove (photo above). Fall fertilization has proven to be a good way to build nitrogen reserves in native pecan trees, boost yields, and reduce alternate bearing. We generally make this fall application soon after Oct. 1 but wait to time the application to coincide with a rainfall event. This morning, we had a brief shower (.11 inches) so we decided to rush over to the COOP and pick up a load of urea. The ground was still damp when we applied the fertilizer allowing the urea to melt into soil almost immediately.
    Next March we will make another fertilizer application but will add potassium to the mix. Our normal Spring fertilizer application is 150 lbs. urea and 100 lbs. potash/ acre  (69 lbs. N and 60 Lbs. K).

2011 Pecan Harvest Walk

Pecan Experiment Field
Tuesday Oct. 11
1:30 PM

When the 2011 growing season began we originally had planned of holding a full day pecan field day at the Pecan Experiment Field. And then the hot, dry summer hit. At several times during the growing season, I was afraid that this year’s pecan crop would be a total failure. No rain, 100 degree temperatures, and gaping cracks in the soil all combined to make our trees look terrible. By the end of August I decided that 2011 was not a good year to promote pecan culture. Area farmers were disheartened by a dismal corn crop, poor stands of soybeans and a total lack of forage for cattle. Everyone was worn out by the oppressive heat. So I cancelled our field day plans.

Fortunately, in mid-September we had some much needed rain. That one rain event turned a poor quality pecan crop into a good quality crop. However, by the time things turned around it was too late to get a full field day put together.

Since we haven’t had this kind of drought since 1980, I think we have a great opportunity to see how the numerous cultivars we have under test have fared under drought stress.  This year is a good time for a Harvest Walk.

The Harvest Walk will be held at the Pecan Experiment Field, located 2 miles East of Chetopa, KS on US HWY 166 and 3/4 mile south 120th Street. We will be holding this meeting rain or shine so come prepared for the weather.  All are welcomed to attend.