Let's talk soil chemistry

Discussion in 'Organic Lawn Care' started by Elden, May 1, 2008.

  1. Elden

    Elden LawnSite Member
    Messages: 137

    I just got back 3 soil test I sent off. It was from a yard that was hydroseeded about a year ago.

    The first one was a soil crust that had formed all over most of the yard about 1/4" thick. Here are the results

    P = 7lbs/A
    K = 108lbs/A
    Mg = 52 lbs/A
    Ca = 231lbs/A
    pH = 5.0
    Buffer pH = 7.8
    CEC = 2.5

    The Second sample was of the soil excluding the crust

    P = 5lbs/A
    K = 40lbsA
    Mg = 17lbs/A
    Ca = 115lbs/A
    pH = 4.8
    Buffer pH = 7.75
    CEC = 2.4

    And the third was of the soil and the crust sampled together

    P = 5lbs/A
    K = 60 lbs/A
    Mg = 33lbs/A
    Ca = 189lbs/A
    ph = 5
    Buffer pH = 7.8
    CEC = 2.5

    I am fine w/ the pH, buffer and CEC, But what I find confusing is that in the top 1/4 inch of soil there is double the calcium and triple the magnesium
    In the top 1/4" the Ca/Mg ratio is 1:4.4 and in the regular soil w/o the soil crust is 1:6.7
    Potassium is more than 2 and a half times higher in the soil crust than in the regular soil.

    Could this hydroseeding mix have caused this issue?

    What element or elements or ratios there of, are causing the soil crust to form?
  2. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,334

    Perhaps dolomite?
  3. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    That is interesting.
    Are certain elements in the soil - hydro-sorted? More easily than others?
  4. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    I think Kiril is saying that someone may have applied too much of a good thing, dolomitic lime which has Mg in it. Calicitic lime does not have much Mg in it.

    I would like to see the readings instead of the suggested applications rates to correct the top 6 inches of soil.
  5. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,334

    Yup. :) :clapping:
  6. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    That makes sense.

    I just looked at the elements went with their constiuent inorganic soil. So as the clay sifted to the top the elements that liked clay went with it. But I don't even know if that's true. :)
  7. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    I am not following you at all on this, please explain

    Could you post the actual readings of the soil? I am not really interested in what they suggest
  8. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I was speaking general terms.
    Whether anyone know if minerals hydro-sort the way mineral sands hydro-sort. i.e. Sand separating from clay overtime. Particularily, in the occurance of 'puddling', due to over-irrigation.

    But as was stated - in this particular case it was likely a topdressing that changed the crust.
    Good idea on Elden's part to do that. :)
  9. Elden

    Elden LawnSite Member
    Messages: 137

    There was nothing incorporated into the soil it was simply hydroseeded the guy who did it is supposed to be a degreed agronomist. He didn't say anything to the guy about how poor the soil was because he did not pay the soil consultation fee only for the hydro seeding (if you ask me that is horrible business. You know its not going to do good but you go ahead and do a $1,700 job anyway to put money in the bank. But that's another issue)

    Those were the actual readings.

    Base Saturation of the soil crust was 5.5% K, 8.6% Mg, 22.8% Ca, 63.2% H

    just soil was 2.1% K, 2.9% Mg, 11.9% Ca, 83.0% H

    Soil and Crust was 3.4% K, 6.0% Mg, 20.7% Ca, 70.0% H

    Oh and I for got to post the SOM reading, It was 0 on all 3 test
  10. treegal1

    treegal1 LawnSite Gold Member
    Messages: 3,911

    wow no SOM, that not good. this sounds like a basket case. my recommendation, start over with some new every thing. this is a shame to say but wheres the good in this story. poor silly customer, save a buck and spoil the yard. I would perhaps re test with another test co. if you are not really confident of there results.

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