Harvest season ends

   We worked hard during the week before Christmas to finish up our second pass over the grove with the harvester (photo above). And its a good thing we did! It started raining on the day after Christmas and continued raining for 3 days. All total, over 6.5 inches of rain fell on the Pecan Experiment Field during this winter storm. By Sunday night the Neosho River spilled over it banks and began flooding our pecan groves.

        By Monday morning, flood waters covered the road to the Experiment field  (photo above). Fortunately, our buildings and the pecans stored inside those buildings stayed well above this flood.  Once we can return safely to the farm, we will need to finish cleaning the 2015 pecan crop and get those nuts sold.

First year grafts: What can happen when you're not watching

   With all the recent rainfall, this year's pecan harvest has come to a halt. Although I'd rather be out harvesting nuts, the muddy field conditions gave me the opportunity to check on some of the young trees I grafted last spring. While most trees looked great with strong, well-calloused graft unions and a single central leader, I found two trees that got overlooked.
    The tree pictured at right was grafted during the spring of 2015.  It is clear that I made at least a couple of trips back to this tree after grafting. A month after grafting, I trimmed the scion down to a single new shoot and attached a bamboo training stick. In mid-summer, I used orange flagging tape tie the new shoot to the bamboo stick. Unfortunately, that was the last time I worked on this tree.
   In response to a summer of plentiful rainfall, this graft kept growing well into August. The new graft out-grew the bamboo support stick and produced  numerous stalked buds near scion's apex. These stalked buds began growing in late summer and created a dense cluster of foliage at the very top of the tree. All of a sudden the tree became "top-heavy" and a strong wind snapped the graft in two.
   To prevent this kind of damage, I should have returned to this tree last August and replaced the small bamboo stake with a longer and stronger stake. Also, I should have made sure to pinch off all stalked buds that kept forming the way into mid-September. For now, I'll leave this tree alone until next spring. When buds start to grow on the scion below the broken stem, I'll chose one new shoot to be my central leader and prune off the broken top.
    

   The tree pictured at left is a great example of what can happen when you simply- "graft and forget". For some unknown reason, I never revisited this tree after placing a graft on a vigorously-growing, seedling rootstock last April. The scion sprouted one strong shoot from the top bud on the scion (red arrow) and two weaker shoots from the lower bud. The stock tree also sprouted several new shoots from below the graft. Two stump sprouts (yellow arrows) grew so fast they achieved twice the diameter of the scion shoot.
    Next spring, I'll need to prune off all the stump sprouts, trim the scion to a single shoot, and place a strong stake next to the tree to help train the tree. Since the two biggest stump sprouts grew from roughly the same spot but on opposite sides of the trunk, pruning them off will leave two narrow strips of bark on either side of the trunk. Ultimately, these pruning wounds will heal over, but until they do, my pruning efforts will create a weak point in the tree's trunk. Tying the tree to a strong stake should prevent the development of fractures in the trunk.

Harvest

     Sometimes, when I see something unique in the pecan grove,  I have to stop and find a way to photograph that moment. Last week, while harvesting pecans with our Lockwood harvester, I noticed how the bright winter sun cast long shadows across the orchard floor. It is not often that I take self portraits, but I thought the photo at right was an interesting way of recording the 2015 harvest season.

Scab resistant cultivars shine in 2015

Kanza trees just before shaking, 2015

   During the rush of harvest, I've made two important observations about the impact of pecan scab on nut production.
   1. This past summer, I made the decision to concentrate the dollars we spent on fungicides to protect improved but scab-susceptible pecan cultivars such as Pawnee, Giles, and Chetopa. We made three fungicide applications on these trees and achieved good but not perfect results. This fall we were able to harvest good crops of quality pecans from most improved cultivars (Hirschi and Dooley were exceptions). In contrast, I decided save money by making only a single fungicide application to our native pecan trees in the hope we could suppress scab enough to ensure a decent native crop. Unfortunately, my gamble didn't pay off. We are harvesting far fewer native nuts that I originally expected. When I shake our native trees, I'm seeing far too many black, scabby stick-tights hit the ground. It seems that 2015 was not a good year to experiment in cutting back on fungicide costs.
   2. Once all the leaves fell from the trees this fall, I noticed that trees with genetic resistance to pecan scab tended to be the heaviest nut producers in 2015. The scab-resistant Kanza, Lakota, and Major trees all produced heavy crops of high quality nuts. Although our fungicide program provided fair scab control on scab susceptible cultivars like Pawnee, Giles, and Chetopa, yield for these cultivars were good but not great.
    The 2015 growing season has made many new believers in the need to propagate scab-free pecan cultivars in their orchards. I know I'm grafting only scab resistant cultivar on my home farm next spring.

Revisiting a top-worked pecan tree

   We might be busy harvesting pecans this week but, I couldn't resist taking a photo of a tree that I top-worked back in 2012 (photo at right). Frankly, I was amazed at how well the tree had grown and was glad to see that all my pruning efforts yielded a nice central-leader tree.
    You can see how I grafted this tree and then trained the scion into a central leader by going back and reviewing previous blog posts I made about this tree. Click on the blog post titles to link back to those posts.

1. Top-working with a bark graft
2. Bark graft bursting
3. Training a new bark graft 
4. Summer training a bark graft
5. Summer pruning last year's bark graft
6. Directive pruning results

    Since I first grafted this tree, the scion has had four summers of new growth. The photos at left give you an idea how well this graft has grown. The cut surface on the stock tree has completely healed over and I now have a nice solid graft union.  In the 2015 photo, I've placed a red arrow to mark the spot where scion and stock meet. Notice the abrupt change in bark texture between the stock tree below and the scion above the red arrow.

     And finally I wanted to remind you why I needed to top work a fairly large tree in the first place. The 2012 photo at right shows the original tree before I started the top-working process. This tree had been severely damaged by an ice storm in 2007 and had grown into a tangled mess. Since the tree was originally grafted to the wrong cultivar for that location, I decided to change the tree over to the right cultivar and work on proper tree training all at the same time. By the end of the 2015 growing season, it looks like I've got a well shaped tree well on the way to nut production.

Starting pecan harvest

    We were able to start pecan harvest this week (photo above). The first trees that we were able to shake were some young Faith and Gardner trees in our "double-row" tree planting. Because we were harvesting experimental plots, we used our old Lockwood pecan harvester along with our small trunk shaker. Besides Faith and Gardner we were also able to harvest some Osage, Witte and Pawnee trees. Unfortunately, yesterday's rain showers has put a stop to our harvest for the time being.
    In cleaning the nuts we harvested this week, I noticed that the pecans were not fully dry. During the cleaning process, green shucks were knocked off nuts but that still left us with a sack full of nut that needed additional drying time. We placed cleaned pecans in burlap bags which will allow the nuts to dry down while being stored in the barn. 

A Kanza story

    Back in 1969, Dr. G. D. Madden, the USDA's pecan breeder at the time, sent a package of scions from several pecan selections to the Pecan Experiment Field for testing under northern growing conditions. Among those scions was a clone labeled USDA 55-11-11.  Back in those days, the staff at the Pecan Field grafted all new cultivars received for trial onto small native pecan trees that grew within areas of larger native trees. As it turns out, only one USDA 55-11-11 tree was successfully produced from that spring's grafting efforts and has now grown into a large tree (photo at right).
     When I first arrived at the Pecan Experiment Field in 1981, our 55-11-11 tree was already bearing regular crops of nuts. During the early 1980's, KNGA member, pecan enthusiast, and parish priest, Tony Blaufus made an annual trip to the Pecan Field to look over our cultivar collections. Tony had started a small grove of trees on his family's farm near Westphalia, KS and was interested propagating the best available pecan cultivars he could find. It was Tony that first pointed out  to me how well nuts from the 55-11-11 tree shelled out and how wonderful the straw-colored kernels tasted. That's when I decided to remove a couple of nearby native trees to give our lone 55-11-11 some more room to grow. I also started to graft additional USDA 55-11-11 trees into formal cultivar trials.

      In the early 1990's, I started to encourage the USDA to name and release USDA 55-11-11 as a new pecan cultivar for northern pecan producers.  I even suggested a name--Kanza.
    In 1996, Kanza was released and has since become one of the most popular nuts being propagated in northern pecan states. And what has happened to that single tree grafted back in 1969?  It is still standing and has grown to 25.1 inches in diameter (Photo at left).
    I have been fortunate to be able to watch a single Kanza tree grow from a young productive nut producer into a fully mature tree that reliably yields outstanding-quality pecans year after year after year. In the past, we've made cultivar choices based on the performance of young trees only to be disappointed by those same cultivars as trees mature. Too many times, I've seen cultivars that produced outstanding nuts on productive young trees only to mature into old trees with severe alternate bearing, poor quality kernels and susceptibility to winter cold damage. With Kanza, I've been able to watch this cultivar long enough (35 years) to know I won't be faced with future disappointments. 

     Kanza originated from a hand pollinated cross between Major and Shoshoni made by Louis Romberg in 1955. Louis was the USDA's first pecan breeder hired way back in 1931. The objective in making a cross between a northern cultivar (Major) and a large, thin-shelled cultivar of southern origins (Shoshoni) was to develop a new pecan cultivar with large nut size, thin shell and early ripening. The photo at right shows a Kanza nut and its shuck. When I look at Kanza, I can see characteristics from both parents. Kanza inherited the tear-drop shape, thin shell and excellent shelling ability from its Shoshoni parent. From its Major parent, Kanza inherited scab resistance, a thick firm husk, early ripening, and great kernel flavor.
     In the 1960's, many pecan "experts" judged USDA 55-11-11 not worthy of propagation. The nut produced was deemed too small for modern commercial orchards that only had room for cultivars that produced mammoth sized nuts.  At that time in our history, it didn't seem to matter if those big pecan produced kernels that tasted like cardboard. But times change, and consumers are becoming more concerned with kernel quality and flavor rather than just a big shell.  

    Kanza is among the best shelling pecans that can be grown. After cracking, Kanza nuts produce over 95% intact kernel halves (if the cracker is set properly). The kernels are golden in color and very attractive (photo at left). Get a customer to taste a Kanza kernel and you'll have them asking for the nut by name from now on. 

Waiting for harvest

   

    Over the past week I've noticed a major change in our pecan grove--the trees have taken on their fall colors (photo at right). Pecan trees never develop flashy fall color but, as the trees prepare for winter dormancy, leaves will yellow then turn quickly to brown before falling from the tree.

   The trees pictured above are grafted to the Gardner cultivar. I walked up to the nearest tree to check on the condition of the nut crop. Even though Gardner nuts has been shuck split for about a month now, the shucks were still green, almost completely covering the nut inside. Sure I could shake the tree at this stage, but that would force me into dealing with green shucks on the cleaning table and a bin full of wet nuts.

  With green shucks still covering the shell, pecans don't dry well. I harvested a couple of nuts and pulled back the shuck to reveal free moisture on the outside of the shell (Photo at left). A quick taste of the kernels inside these damp shells revealed that the nut meat was rubbery and "green" tasting (both indications of high moisture content).
   Harvesting pecans with high moisture content runs the same risks a harvesting grain before fully dry. Wet nuts can mold, heat up, and destroy pecan kernel quality.  If pecans are harvested with high moisture content, they must be dried using a forced air system to remove kernel moisture as fast a possible.
   At the Pecan Experiment Field, we don't have the time or resources to dry large quantities of early-harvested pecans. So we wait for nature to dry the crop. What usually happens is that a killing freeze in early November will kill green shucks. This allows the shucks to finally dry, pull back away from the nuts, and the nuts will dry on the tree.  So for now, we'll wait.

Mid and late October ripening pecans

Chetopa, 19 Oct. 2015

     I've been so busy collecting nut samples in our pecan breeding block that I almost forgot to record photos of some mid and late October ripening cultivars. I completely missed the actual date when Giles and Chetopa ripened but from the photos I took on 19 Oct. 2015 it looks like they had split at least 7 days earlier (photos at right and below). In comparison, Maramec, Oconee, and Stuart have split during the third week of October (photos below).
   In looking over these nut photos, note that Giles, Chetopa, and especially Maramec have scab-infected shucks. Fortunately, the level of scab infection on these shucks did not prevent shuck-split. Oconee and Stuart nuts were free of scab.

Giles, 19 Oct. 2015

Maramec, 19 Oct. 2015

Oconee, 19 Oct. 2015

Stuart, 19 Oct. 2015

Hand harvesting nut samples

    Over the past week, I've been harvesting nut samples from each of the trees in our pecan breeding block. This is a slow but exciting process. Because the trees in the breeding block are planted fairly close together, I harvest samples before nuts start to drop to make certain I collect the right nuts for each tree. This means getting up in our hydraulic lift and pulling off nuts still inside their green but split-open shucks. By harvesting nuts this way I have the opportunity to take important notes on scab resistance.

    As I harvest each nut sample and remove the nuts from the shucks, I think about the potential for that tree to become a new pecan cultivar. In selecting nuts for future testing, my priority is to find new pecan cultivars that have good resistance to scab and excellent kernel quality. Nut size is important but if we have learned anything from our experience with Kanza, customers can appreciate a good tasting medium-sized pecan over a large nut that tastes like cardboard.
     The photo above shows some of the nuts I collected late last week. In the top row I have two Pawnee nuts followed by two Kanza nuts. Pawnee and Kanza are the standards by which I measure all potential new cultivars. Nuts from ten different trees in the breeding block are shown in the middle and bottom rows. These ten were among the numerous trees that showed good scab resistance in a year with heavy scab pressure. As you can see the nuts come in all sizes and shapes. Still to be determined is how well these nuts shell out and the quality of the kernel inside the shell.
     

Dooley and Hirschi crops destroyed by scab

    Thirty years ago, the Dooley pecan cultivar was the nut prized for home consumption by all the workers at the Pecan Experiment Field. Although not a large nut, Dooley shells out in halves producing a beautiful light colored kernel with outstanding flavor. However, over the years this cultivar has become increasingly susceptible to pecan scab. In 2015, our Dooley trees received the same three applications of fungicide that we sprayed on all of our pecan cultivars. Somehow, Dooley nuts still became covered with black scab lesions (photo at right).  This year, the Dooley crop will be 100% stick-tights and we'll suffer a total crop loss on this cultivar.

 

  Hirschi was another cultivar that suffered from extreme scab infection in 2015.When I inspected the crop on our Hirschi trees, I found that some shucks had split in spite of a 100% scab infection. The photo at right gives you a good idea of how scab effects nut production. The Hirschi nut cluster on the left side of the photo was photographed in Illinois and was largely free of scab infection. The scab covered Hirschi cluster came from our trials in Kansas. Nut size is significantly smaller for the Kansas grown Hirschi pecans where shucks are covered in scab.
    The difficultly we've experienced controlling scab on Dooley and Hirschi in 2015 has also occurred in previous growing seasons. Our inability to control scab on these two cultivars means that I definitely won't be grafting any more Dooley and Hirschi in the future.

Pecan cultivars ripening during first week of October

Caddo, 8 Oct. 2015

  Yesterday, I took a quick tour of our research trials to find pecan cultivars that ripened during the first week of October. I found that Caddo, Chickasaw, Greenriver, Jayhawk, Lakota, Niblack, and Oswego had split shuck since the last time I checked our cultivar trials on September 29th (photos at right and below) . Judging from the crop loads I'm seeing on all trees, both improved and native, 2015 will be an excellent harvest year.

Chickasaw, 8 Oct. 2015

Greenriver, 8 Oct. 2015

Jayhawk, 8 Oct. 2015

Lakota, 8 Oct. 2015

Niblack, 8 Oct. 2015

Oswego, 8 Oct. 2015

Fall nitrogen fertilization

  

Since the weather forecast calls for a 60% change of light rain tonight, we decided to apply our fall fertilizer today (photo at right). Hopefully, a light rain will fall over night, melting the fertilizer pellets  and washing the nitrogen into the soil.
    Our fall fertilizer program calls for the application of 100 lbs./acre of urea, which amounts to 46 lbs./acre of actual nitrogen. We broadcast this fertilizer over the entire orchard using a standard buggy we rent from our local fertilizer dealer.
   This fertilizer application is timed to coinside with the fall flush of pecan root growth that occurs as the trees start to prepare for dormancy. Actively growing roots are far more efficient at taking up soil nutrients than roots that are quienscent.

Nut shape defines kernel characteristics

   The other day I was cutting pecans in half to check on kernel quality when I made a simple observation. Nut shape has a huge impact of a couple of important pecan kernel characteristics.
    As I walked down one of our tree rows, I came across three early-ripening cultivars; Faith, Gardner, and USDA 75-8-5. In cross-section,  Faith and Gardner have a similar nut shape--nuts are wide and seem flattened on the suture side (photo above). In contrast, nuts of USDA 75-8-5 appear narrow when viewing the nut from the suture side but are wide in the opposite direction.
    When kernels are extracted from these nuts Faith and Gardner kernels will appear much larger than the 75-8-5 kernels simply because they will be much wider. Now, look at the shell packing material that fills the space in the dorsal grooves of each kernel half. Note that the packing material forms a wide "V" shape in the Faith and Gardner nuts. In comparison, the USDA 75-8-5 nut has narrow fingers of packing material inside deep dorsal grooves.  Narrow dorsal groves often trap bits of packing material in kernel halves making the shelling process more difficult. The "V" shape of the dorsal grooves inside Faith and Gardner nuts will mean that all fragments of packing material will fall free from the kernels during nut cracking.
     

Pecan cultivars spliting shuck in late September

Waccamaw, 28 Sept. 2015

    Over the weekend six more pecan cultivars started to open their shucks. Pictured at right is a seedling cultivar of unknown parentage that originated outside of Golden City, MO. The tree's owner named the tree Waccamaw, after a native American tribe that once inhabited coastal South Carolina. The Waccamaw River flows from North Carolina into South Carolina running parallel to the eastern seacoast. The Waccamaw produces a nut slighty smaller than Pawnee and yields 54% kernel. Waccamaw is scab susceptible.

City Park, 28 Sept. 2015

 

   





     Another seedling pecan we have under trial is "City Park". Years ago, we planted a Giles seedling in Chetopa's Riverside Park. Eventually, the tree started to bear nuts. I was so impressed by the size of nuts produced by this tree that I grafted scions from the original tree into field trials at the research station. The grafted trees of 'City Park' have now matured enough to allow us to get a good read on it ripening date--about the same time as Kanza.

Kanza, 28 Sept. 2015

    Speaking of Kanza, our heavy crop of Kanza nuts have begun to split shuck. Spotting shuck split on Kanza is a little difficult. The shuck separates down the sutures but remain fairly tight around the nut. It will take a killing freeze to really open up the shucks and release the nut inside.

Hark, 28 Sept. 2015

     Like Kanza, I have a strong suspicion that 'Hark' has Major as one of its parents. As a result, the shucks of Hark split down the sutures but the shuck remains tight around the nut until frost.

Posey, 28 Sept. 2015

   















      Posey has a very distinctive shuck that is characterized by a rough surface texture and prominent wings along the sutures. At this time Posey nuts are about 10% shuck split.

Yates 68, 28 Sept. 2015

   Yates 68 looks to be a Posey seedling and shares Posey's dark shell color and tendency for kernels to turn dark quickly after harvest.  Yates 68 was selected from a group of seedling trees planted by Ed Yates on his farm in Southern Indiana. 

Scab on 'Mandan' pecan

    The cultivar release notes published when Mandan was first made available to the public claimed that nuts produced by this tree are resistant to pecan scab. Although not extremely susceptible to scab we have found Mandan shucks infected with the disease.
    This past season we applied a fungicide three times to our Mandan trees during the months of June and July. For the most part, we have kept the shucks mostly clean with only a few small scab lesions appearing by late summer (photo at right).

   However, where we didn't get good fungicide coverage on the nuts, I found several clusters of Mandan nuts covered with scab lesions (photo at left). Mandan also seems to be susceptible to powdery mildew.
    While taking this photo of scabby nuts, I found a crab spider resting on one of the nuts. Crab spiders are a common insect predator in pecan tree canopies with female spiders often hiding their eggs at the base of nut clusters.

More pecan cultivars ripen in late September

Colby, 25 Sept. 2015

    This morning I took a ride in our hydraulic lift so I could get up into pecan tree canopies to check on nut ripening. I found that 10 more cultivars had split shuck including; Colby, Gardner, Goosepond, Major, Mandan, Pawnee, Peruque, Witte and two USDA selections 63-16-182 and 64-11-17 (photos at right and below).
    Among the cultivars I photographed today only Major is resistant to pecan scab. While most cultivars in our trials received 3 fungicide applications, our Goosepond trees are located within a native grove and receive only a single spray. As a result, all the Goosepond nuts were covered with scab. What I found interesting was that many Goosepond nuts still split shuck and will release a smaller-than-normal but sale-able nut.
   Colby and Peruque nuts exhibited high levels of scab despite receiving 3 doses of fungicides. The difficulty we have controlling scab on Peruque and Colby is just one reason among others that these northern cultivars are no longer being grafted into new orchards.

Gardner, 25 Sept. 2015

Goosepond, 25 Sept. 2015

Major, 25 Sept. 2015

Mandan, 25 Sept. 2015

Pawnee, 25 Sept. 2015

Peruque, 25 Sept. 2015

Witte, 25 Sept. 2015

USDA 63-16-182 ('Eclipse'), 25 Sept. 2015

USDA 64-11-17, 25 Sept. 2015