Phosphorus

Discussion in 'Organic Lawn Care' started by Smallaxe, Jun 25, 2009.

  1. WannaBeOrganic

    WannaBeOrganic LawnSite Member
    Posts: 90

    drug rep, maybe you are better at chemistry than me and can answer these questions.

    I think the P on the bag really means phosphorus pentoxide. Saying N-P-K is a lot easier than saying N-P2O5-K2O.

    Phosphorus pentoxide is a desiccant (drying agent) wouldn't high amounts cause other issues?

    Too much P doesn't sound good.
     
  2. phasthound

    phasthound LawnSite Platinum Member
    Posts: 4,575

    Stop obsessing about P, add organic matter.
     
  3. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Yikes! :dizzy: This could be a full time job dispelling all the inaccurate information thrown out there by our new resident "expert" who claims to understand what he regurgitates.

    The values of P and K are reported this way because historically it was how the mass fractions of P and K were determined/analyzed and reported. It has nothing to do with the actual composition of the fertilizer.
     
  4. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,080

    So what does this have to do with P in lawns. This is about solids in waste water moving with the waste water into the water table. It is already understood that if the solids they are attached to move, then we have movement of the P.

    That is why I specifically asked for peoples' thoughts. With discussion there is the need for all parties involved to understand the question and the response. Throwing out a list of papers does not require a forum, only a google.

    Will P - as a nutrient currently in the soil - leach out, disengage, break the molecular bond, of the soil? and if so how does that happen?
     
  5. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Ask yourself how P is taken up by plants and you will have answered your own question.
     
  6. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,080

    I remember the discussion about nutrients being freed up by microbes at the request of the plant. But that these microbes were everywhere and the question was - Would these microbes be releasing nutrients in the soil, where there were no plants growing?

    Turns out the answer was - Very little activity without plants.

    Anyways, a P molecule has to get into the sap stream to be transported throughout the plant. So a P molecule has to be stripped from whatever it is bound to and be water soluablized.
    That is NOT done by rain water washing through the soil and leaching into the water table. As is the case with N.

    So if a P molecule is wrestled off a Cation Exchange Site and becomes water soluable , but is not used by a plant right away -- How far can it possibly travel b4 getting bound to another CE site? Answer - Not very.

    So here the answer of my own question is that P does not leach and it is doubtful that what is applied gets beyond the layer of thatch in most lawns.
    Since nothing is out there to prove this concept to be wrong -- I will continue on as if it were true. So far as our science can tell - it is true.
     
  7. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Axe, you didn't answer the question. What is the primary transport mechanism of P from the soil to the plant?

    P can leach, in solution or by particulate matter moving through the profile. The amount of leaching that can occur is strongly soil dependent.

    My list for you. ;)

    http://www.omafra.gov.on.ca/english/crops/field/news/croptalk/2003/ct_1103a11.htm

    http://toxics.usgs.gov/highlights/phosphorous_migration.html

    http://soil.scijournals.org/cgi/reprint/64/3/1090.pdf

    http://soil.scijournals.org/cgi/reprint/68/4/1429.pdf

    http://jeq.scijournals.org/cgi/reprint/37/1/69.pdf

    http://jeq.scijournals.org/cgi/reprint/34/1/370.pdf

    http://jeq.scijournals.org/cgi/reprint/33/2/678.pdf
     
  8. drugrep

    drugrep LawnSite Member
    Posts: 44

    Kiril, If you are referring to me, I do apologize if I've ever come off that way. I barely understand this stuff which is why I am here getting opinions. I've got a lot of great information from you, smallaxe, and WBO and am trying to assimilate and balance it to meet the goals I want to meet and good technique.

    I do want to get my numbers right which is why I will continue to use synthetic for now, but I strongly believe in organic matter which is why I began mulching this year and adding protein. Trying to get best of both worlds until I can make full switch to organic.

    2 labs told me to use balanced fertilizer year round. Like 12-12-12, but I don't want the K, so I decided to use Starter. You guys have me thinking about trying to do it too rapidly, so I will probably just use starter May 1st and Sept 1 and then use things like Soybean meal rest of time.

    I value and appreciate all of your input. I may not listen to all of it even if I know you're right. I do understand some Chemistry, but am no expert. 1 Semester of General and 1 Semester of Organic.
     
    Last edited: Jun 27, 2009
  9. drugrep

    drugrep LawnSite Member
    Posts: 44

    I will say 1 thing though with conviction. Befvore I say it, let me say that I do strongly believe in feeding and nurturing microbes and doing things like grasscycling to increase organic matter. So here it is, I do think the strict organic group have overblown the effects of synthetic fertilizer. Some people need it and using it plus organic techniques is perfectly acceptable. That point I will argue until we're both blue in the face.:):drinkup:
     
  10. growingdeeprootsorganicly

    growingdeeprootsorganicly LawnSite Senior Member
    Posts: 766

    once phosphorus is ionized to a water soluble phosphate salt it has water leaching capability, the earths natural phosphorus cycle depends on it for life as we know it to exist:).
     

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