Wet spring delays application of fertilizer to pecan groves

    The wet weather cycle continues with above average rainfall covering much of the Midwest. Since January 1, 2020, we have received twice our normal amount of precipitation on our farm. Needless to say, the soils in my young pecan orchard are saturated with puddles of standing water everywhere (photo at right).
    I usually make my Spring application of fertilizer during the month of March, but until things dry up a bit, I won't be able to pull a fertilizer buggy across the orchard.

    I typically watch for the first signs of bud swell to make the Spring fertilizer application. So out of curiosity, I checked bud development on some of my Kanza trees. The buds were still fully dormant (photo at left).  This means, that even if the ground was dry, I would be holding off on fertilizing at this time. Once I see bud swell, I'll spread some N, P, and K as soon as the soil becomes passable.

    The Neosho River spilled over it banks yesterday and moved into many native pecan groves in our area (photo at right).  The frequency of springtime floods in many native pecan groves is the primary reason I started recommending spreading a portion of the tree's fertilizer needs in the Fall. With fall fertilization, I can be certain that trees have enough stored nutrients to make vigorous new shoots in the spring. Then, when the soils dry out, more fertilizer can be applied to sustain both shoot and nut growth during the summer months.
      

Third flood this year on the Neosho River

   Over the past 3 weeks, we have received over 14 inches of rainfall--That's one third of our normal annual total. Within this same period, the Neosho River has spilled over it banks 3 times. Currently, the water is still rising (photo above) with the crest not occurring until sometime Friday. This current flooding event is predicted to rival the flood we had in April of 1994; the fourth highest flood on record.
    

    My pecan orchard is located over four miles from the Neosho but river water has backed up and is covering the ground under my young Kanza trees (photo above). Fortunately, pecan trees can tolerate flooding and even grow best in flood plain soils. In time, the water will recede but I'll be left with a mess to clean up. It's always amazing to see what a flood can float onto the orchard floor.  Once the ground dries up, I'll get it cleaned up with a tractor and rake. 

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.

Spring flood on the Neosho

   The entire Mid-west region was hammered by heavy rains over this past weekend. At the Pecan Experiment Field, we recorded almost 4.5 inches of rain for Saturday April 29 and Sunday April 30. With all this rainfall, the Neosho River has spilled over its banks and covered the pecan groves in the Chetopa, KS area. Today, I drove down the highway to get a good view of the flooding (photo above). More rain is predicted for this week and the river is forecast to stay flooded until Thursday (May 4th).
   Flooding is a natural part of the native pecan ecosystem. Pecan trees tolerate flooding for short periods of time (less that 10 days) but fibrous pecan roots will start to die if soils remain flooded for a long time (more that 3 weeks). 

Wednesday May 3rd update:

Another 2 inches of rain today, which means our flood will continue for the rest of the week. Below is a chart of the Neosho River level at Stepford bridge which is located just a couple of miles down river from Chetopa. When the river reaches 18 feet, water begins to cover the road to the Pecan Field. At 24 feet, we will start to get water in our buildings. This flood, at 22 feet, will cover all areas of the farm but should stay out of our buildings. Next week, we'll find out how much flood related debris there will be to clean up. 

Early October flood on the Neosho

   This week, parts of SE Kansas received over 12 inches of rain in a 3 day period. The Neosho quickly filled and has now spilled over it banks, flooding both the Pecan Experiment Field and surrounding native groves (photo above). The National Weather Service is predicting only a moderate flooding event that should last about three and a half days. Fortunately, we had not yet made our regular Fall fertilizer application. If we had spread nitrogen on the grove earlier this week, it would have ended up down in Grand Lake instead of helping our trees. After the flood waters recede and the orchard floor dries up, I'll be checking the weather forecast closely to choose the best time to spread some fertilizer later this month.

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.

Recharging the water supply

 
     Over the last few weeks, we have received an abundant amount of rainfall. So much rain fell over southeastern Kansas last weekend that the Neosho River spilled out of its banks and flooded our pecan grove (photo above).
   There are positive and negatives when it comes to flooding. On the plus side, a low level flood, like the one we are experiencing now, is serving to recharge the subsoil water supply. Every since the extreme droughts of 2011 and 2012, we have never received the surplus rains needed to completely recharge the system. This flood should get us back to full water supply.
    The downside of flooding is a loss of soil nitrogen due to the actions of denitrifying bacterial that flourish in flooded soils.  Based on predictions from the National Weather Service, this flood should last about five days. That's long enough to recharge the soil moisture supply but not long enough to throw our trees into nitrogen deficiency.

  Update Friday May 29th: The National Weather Service  operates River Forecast Centers all across the country. If your pecan grove is in a flood plain you should go to the NWS website and find the closest reporting site on your river.  We use the data recorded just south of us on the Neosho River to predict how flooding will impact the Pecan Experiment Field. The data above is a screen shot from Friday, May 29th.  Water covers the road to the Pecan Field when the river hits 18 feet. At 24 feet, we will have water in our buildings. The biggest flood I've lived through and the second highest in recorded history occurred in early July of 2007. On July 5th, the river crested at 29.25 feet and we had 5 feet of water in our workshop.
   The rain received today will extend local flooding conditions (see chart above) and will cause some of our trees to be under water for more that a week's time. This will cause low nitrogen problems for trees in lowest lying areas. With a big crop set on the trees, I'll be adding more N fertilizer to several tree blocks once the flood recedes.  

Rain changes everything

Soil Crack, summer 2011

   The summer's of 2011 and 2012 were hot and dry. It wasn't that long ago that I was taking photos of massive cracks in our river bottom soil (photo at right). Our trees suffered through those dry years producing a crop each year, but a crop with much smaller nuts. Earlier this year it looked like we were headed for another dry summer with little or no rain falling in June and early July. We were missing every 30% chance of rain and I was preparing myself for a third year of drought. Suddenly everything changed.
  









    
    It started to rain in late July and it has continued to rain frequently ever since. We've had over 12 inches of rain during the past 2 weeks and the Neosho River has flooded over its banks twice. The ground cover under the trees is growing like its springtime and we have water everywhere (photo below).

    All this moisture and humidity has led to weevils emerging and pecan scab spreading. Unfortunately, with showers falling nearly everyday and super saturated soil conditions it has been impossible to spray for these key pecan pests. But as soon as we get the opportunity, we will be applying an insecticide for weevil and stink bug control and a fungicide for scab control.
    Today, the Neosho River is starting to fall back into it banks but more rain is forecast for tonight. Another Flood? We'll have to wait and see.

Flooding and new grafts: 2013 results

   Back on June 1, I posted a photo of a newly grafted tree surrounded by flood water (reprinted at right). Unfortunately, the water was still rising when I snapped this photo. Later that night, the graft union on this tree became completely submerged. In my previous post, I stated that a new graft will be lost if flood waters cover the union before the tree has a chance to callus in the scion. Today, I returned to this field to see what actually happened.

    At first glance , the photo at left might look like a successful graft, but all the new growth is coming from shoots that originate below the graft union. Hidden amongst the leaves is a very dead scion. This tree was completely submerged during the flood, giving my grafting effort a 0% chance of success.
   

      A hundred feet away, I grafted a tree a little higher on the stem (photo at right). This tree was also located on a little higher ground (we're talking 1-2 inches at most). Although this tree was also surrounded by flood water,  the graft union remained above the high water mark.  By escaping the flood, the graft placed on this tree remained viable and is now growing rapidly.
     I grafted about a dozen trees in this field in 2013. In every case, graft unions that became submerged in the flood failed. On the other hand, I've had great grafting success on trees with graft unions placed above the flood's peak. 
    I'll let the trees with failed grafts grow out for a couple of years, encouraging them to grow tall and straight. With a larger tree, I can graft higher on the stem and hopefully avoid future problems with floods.

Flooding and new grafts

  

    Flood water  from the Neosho River has backed up over the county road and covered a portion of my young pecan grove. Two weeks ago, I grafted several young trees in that field and I was curious to see how much of each tree was submerged in the flood. In the photo at right, you can see one of my bark grafts with all the wraps poking up through the water.  Its a good thing this graft union was not submerged in flood water. Over the years, we've learned that if a graft union is covered by flood water before the scion has callused into the stock, flood water will kill the graft. If the graft has healed and new growth had emerged from the scion, a new graft can often survive flooding (the sprouted primary bud often dies if submerged but secondary buds break on the scion once the flood recedes).
   This picture was taken during the river level's predicted high point. Hopefully, this graft will survive and sprout new growth shortly. The good news is that all the other grafts I made this year were even higher out of the water than the one in the photo. And I've learned a valuable lesson during this flood, my tree's deer cage will also serve to keep pesky beavers at bay.

Just another Spring flood

 

    Over the past two days we've had 5 inches of rain in the Chetopa, Kansas area. Two to three more inches are predicted for tonight. At this point the Neosho River has already spilled over its banks and many area pecan groves are covered in flood water (photo above). Last year, a Spring flood helped recharge subsoil moisture in our drought stricken pecan groves. In fact, the flood we had on May 2, 2012 was largely responsible for helping make the 2012 pecan crop possible during a year of record heat and drought.  So this year, we welcome another Spring flood to help fill up the subsoil water reserves we may so desperately need come August.

Site selection, water, and pecan performance

    This morning I cut nut clusters from two trees (photo above). Both clusters were cut from 'Faith' pecan trees, and both were taken from trees that have grown to about 5 inches in trunk diameter. The cluster on the left has been shuck split for quite some time and the nuts have decent size. In contrast, the cluster on the right is only now starting to split open and the nuts are tiny, about the size of a small native pecan. What caused this difference in tree performance? Location, location, location.
    The cluster on the left was collected from a tree growing in the Neosho River flood plain growing in Osage silty clay soil. The cluster on the right was collected from a tree growing in Cherokee silt loam soil which is a "second bottom" soil found adjacent to the Neosho River flood plain.
    Small nut size and a delay in maturity is caused by an extreme shortage of water.  Both Osage and Cherokee soils are deep, heavy, and poorly drained. Although Cherokee silt loam has a somewhat lighter texture than Osage silty clay and primary difference between these two soil types in terms of pecan performance in 2012 was position in the landscape. When the Neosho River runs over its banks Osage soils are flooded. Cherokee soils haven't been under water since the melting of the glaciers at the end of the last ice age.
    This past spring we had a flood on the Neosho River which covered all the pecan groves growing in Osage soil. That flood recharged the subsoil moisture lost during the 2011 drought and provided valuable moisture for the 2012 crop. The tree growing in the upland position (Cherokee soil) was not flooded and did not receive enough rainfall during the season to recharge the soil's moisture reserves. As a consequence the tree growing on the upland suffered greatly during our second dry summer in a row.
   When it comes to pecan tree performance,  the importance of good site selection can never be over-emphasized.

A good flood

     Pecan trees are native to the flood plains of major rivers in central and southcentral U.S. These trees are adapted to periodic flooding, and along the Neosho River we seem to have at least one flooding event per year.
     Last Monday night, the area around Chetopa, KS received over 10 inches of rain in a three hour period, swelling creeks over their banks and rapidly filling the Neosho River.  The river spilled out onto the flood plain on Tuesday and peaked on Wednesday.  This flood looks to be a fast rising and relatively fast falling event.
    A flooding event has both positive and negative impacts on the pecan grove. Floods can kill the groundcover and promote denitrification (loss of soil nitrogen). But floods also bring a layer of nutrient-rich silt to the orchard, recharge the water supply deep into the soil profile, and wash away any old pecans left on the ground following last year's harvest.
    This week's flood is high enough to cover the entire orchard but not high enough to cause damage to machinery and buildings.  If we have to live with flooding on the Neosho, this flood was a "good" flood.

Drought is broken

Cattle continue to graze in a partly flooded pecan grove near Chetopa

  Last summer we suffered through heat and drought. In several posts, I shared photos of the soil in our pecan grove cracked open by dryness.  After a warm and dry winter, it has rained every day for 5 straight days dumping around 7 inches of rain on the Pecan Experiment Field and the surrounding area. The heavy rainfall has caused our first flood of 2012 (photo above). As floods along the Neosho River go, this week's "average" flood is more of a nuisance than a disaster. I'm just glad, I was watching the long range forecast and made the decision to delay our March fertilizer applications. With urea costing over $600 per ton, I wanted to make sure our trees received the fertilizer rather than watch all that nitrogen wash down stream. Once things dry up next week, we will get the fertilizer buggy rolling.

Native groves flood

 

     Spring floods are a normal occurrence in native pecan groves. Yesterday, 4 1/2 inches of rain fell over a period of about 36 hours causing flash flooding on many small streams in the area. As Fly Creek ran over its banks, the native trees pictured above became flooded. Pecan trees can withstand a moderate level of flooding, however floods that last more than 2 weeks will reduce tree vigor. In addition, flooding during the growing season (when trees are in full leaf) is more stressful to pecan trees than if the flooding event occurs during the dormant season.

     In flooded soils, soil oxygen reserves become depleted causing two major problems. Without oxygen, tree roots can't respire (breath) and they stop taking up water and nutrients. During extended flooding events, trees will actually suffer from a lack of water being transported up to the leaves.

    The lack of oxygen in flooded soils also causes microorganisms in the soil to steal the oxygen from nitrate molecules causing soil nitrogen to become depleted in a process called denitrification. I have seen pecan leaves yellow during flooding events due to a lack of nitrogen.

    There is not much we can do about flooding in areas where native pecans grow--it is going to happen. What we can do is ensure that the water moves off the field a quickly as possible by improving the surface drainage within our groves.

      There is one more observation I've made about flooding and pecans.  On a section of my own farm I have allowed native pecan seedlings to sprout up where they wish. What's interesting to me is the distribution of the seedlings across the field follows the flooding patterns I see every time we receive heavy rains. Even though the entire field is located in the Neosho River flood plain, seedling trees seem to be clustered in areas that have a little better drainage (photo at right). The "wet" spot in this field has few or no seedlings volunteering to become a part of my future pecan grove. So it seems that pecans can tolerate floods but don't thrive in soils that are excessively wet.