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Soil sample w/ analysis for Oak fertilization

Discussion in 'Plant Health' started by coolbrze, Sep 13, 2016.

  1. coolbrze

    coolbrze ArboristSite Operative

    Mar 10, 2008
    Likes Received:
    Northern VA
    Here's another soil sample we took a few weeks back. Zone 7 if it helps. There is a very lg. / mature Willow Oak that they're wanting to fertilize if need be. What does this analysis show is needed for the Willow Oak (mainly) & the turf? Thanks for the help.

  2. ATH

    ATH Addicted to ArboristSite

    Nov 18, 2006
    Likes Received:
    2-3 lbs of N and 1/2 lb of K and 10 lbs of dolomitic lime per 1,000 sqft is their recommendation... It also says I'd find a lab that recommends based on species rather than just 'mature tree'.
    Jason Douglas and Ghillie like this.
  3. Jason Douglas

    Jason Douglas ArboristSite Operative

    Oct 23, 2016
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    Dont fertilize yet.

    Next time, run the micronutrient test (Fe, Mn, Cu, etc) as well as an OM test.
    With this soil pH, your metal micros could be quite high and your base nutrients Ca and Mg are pretty low. Thats why a dolomitic lime product was also recommended. You can also estimate N totals from % OM.

    Most importantly, how is the tree doing? Signs and symptoms? Running a tissue test earlier in the season IN CONJUCTION with this soil test is the way to go. Remember, fertilizing is like pruning: it can be the best or worst thing that can be done. Perhaps the only thing this tree needs is a bed expansion and supplemental OM applied. Since this tree is large/mature, a maintenance amount of 1 to 2 lbs N per 1000 may be all that is needed. Avoid ammonium and urea N sources as they acidify and that isnt needed here. Since it has lived this long, research the site history to see if the root zone and soil has been disturbed or damaged. If not, and the tree is doing well...dont fertilize. Mulching with compost and wood chip will basically replicate forest soil and is likely all that is needed.
    ATH likes this.

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