Which Fall Fertilizer Should I Use?

Discussion in 'Fertilizer Application' started by joed, Sep 7, 2012.

  1. BTC

    BTC LawnSite Member
    Posts: 150

    I believe everything leaches, but nitrogen much more so than the other macro nutrients.
     
  2. turfmd101

    turfmd101 LawnSite Bronze Member
    Posts: 1,268

    Most Fl palms show P deficiency. A pretty yellow - orange.
    Posted via Mobile Device
     
  3. turfmd101

    turfmd101 LawnSite Bronze Member
    Posts: 1,268

    Posted via Mobile Device
     
  4. Skipster

    Skipster LawnSite Bronze Member
    Posts: 1,074


    We'll see about that.


    From Chapter 5 Phosphorus from Soil Fertility and Fertilizers (7th ed.) by Havlin, Beaton, Tisdale, and Nelson:

    "When H2PO4- is bonded through one Al-O-P bond, the H2PO4- is considered labile and can be desorbed from the mineral surface to the soil solution. H2PO4- bonds to Al, which is bonded to the cation exchange site. In acid soils, P adsorption also readily occurs on the edges of clay minerals. In alkaline soils, H2PO4- bonds to Ca or Mn and remains part of the labile pool on the surface of soil minerals.

    Only at excessively high P concentrations do these compounds precipitate."


    Sorry. Again, the textbook says that P bonds to elements on the cation exchange sites and only precipitates when P concentrations are excessively high.

    That's why I linked it with CEC -- most guys on this board understand CEC and P bonds to elements that are on CE sites. More CEC = more opportunities for P to bond. Less CEC = less opportunities for P to bond. I didn't think everyone else wanted a chemistry lesson, so I simplified it. Maybe it's not precise, but it gets the job done.

    Perhaps you need to review your soil chemistry again.
     
  5. turfmd101

    turfmd101 LawnSite Bronze Member
    Posts: 1,268

    Posted via Mobile Device
     
  6. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,081

    OK thanks... I got the general idea... I was taken aback at first when K was mentioned as NOT leaching but I guess at the tune of 50 to 100 inches of water needed to move it 10 inches, for all practical purposes there's not much to worry about... :)
     
  7. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,298

    And what does this have to do with the P bonding to the cation exchange sites per your statement? What you have quoted here is an incomplete explanation of pH dependent protonation/deprotonation reactions with O and OH groups on layer silicates and metal oxides and how solution P reacts with those groups. This in essence is anion exchange and it is not synonymous with K reactions with the cation exchange complex as you indicated. Nice try skip, you are indeed a world class back peddler.

    It does not say P bonds to cation exchange sites which is what you stated. You can "skip" around that fact all day long, but in the end your statement is still incorrect.


    P is not held on cation exchange sites skip ..... end of discussion.

    And you did so incorrectly. If you can't speak with accuracy, don't speak at all.
     
  8. Skipster

    Skipster LawnSite Bronze Member
    Posts: 1,074

    All my textbooks and all the soil P research I've found say the same thing -- soil P binds to ions that are attracted to CE sites. Thus, they are linked to CE sites such that fewer site means less P bonding and more sites means more P bonding. You have not refuted this.

    Sure, P does not attract to CE sites by itself, but it DOES bond to ions that attract to CE sites. So, instead of trying to confuse everyone, I simplified the issue, and in doing so left out some info. However, that doesn't change the final message about P immobility in soils and you have provided no evidence to refute my conclusion.

    I get that you're trying to nitpick so you can remain the king of some obscure internet message board, but there are no prizes for Message Board King here.
     
  9. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,298

    You confuse people by not providing the correct information. Either the information you present is correct, or it is not. Your information was not correct, so let me repeat myself.


    P is NOT held on cation exchange sites skip ..... end of discussion.
     
  10. Skipster

    Skipster LawnSite Bronze Member
    Posts: 1,074

    So, now the correct information is out. I was not wrong when I said that soil P binds to ions that are attracted to CE sites.

    BTW, you should apologize for this statement, b/c the textbooks and research say that this is largely not true -- it only happens at excessively large P concentrations.

    You're going to have to go back to school for soil chem, too.

    Those who want to throw stones shouldn't live in glass houses.
     

Share This Page