Phosphorous as fertilizer

Discussion in 'Fertilizer Application' started by Victorsaur, Jul 17, 2013.

  1. Victorsaur

    Victorsaur LawnSite Member
    Messages: 81

    This thread is to discuss the usage of phosphorous fertilizer and the counter-arguments involved. So far I've found the following counter-arguments to be most prevalent:

    Phosphorous is so dangerous that it should never be applied.

    Phosphorous is available in the soil and doesn't need to be applied.

    With regards to the first statement, I don't believe that never applying it can be the solution because people will apply it anyway. The purpose of this thread is to elaborate on how to best safely apply phosphorous should it need to be applied and how to minimize or even completely remove the hazards associated with application.

    With regards to the second statement: "It is impossible to tell how much calcium and phosphorus are required without a soil test. However, because most North Carolina soils are low in phosphorus, it is usually safe to add 1 to 2 lbs of P2O5 per 1000 ft^2."

    I've provided the idea that organic fertilizers may be the solution to reducing phosphorous pollution. They are less likely to cause runoff pollution, as stated here:
    The RPR (reactive phosphate rock) mentioned at the end in more detail here:

    A scholarly article would be an ideal source for proving or disproving whether rock phosphate is the best solution.

    According to a flier circling a few websites: organic fertilizers remain more stable in soil, are slower release, and are thus less likely to add to water pollution than synthetic fertilizers.
  2. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I found a few interesting articles that included paragraphs about 'P runoff'(erosion) and even 'leaching'...

    High P soils or soil that have reached their maximum capacity to hold P are at risk for precipitation(leaching) of P through the soils in soluable form...

    Pollution of P comes largely from leaves and decaying forest material under regular circumstances and from everywhere during floods...

    You can read all the scholarly articles you want but the simplest thing to do in Wisco is go to you local rivers and streams during flood stage and think for 2 minutes about all the brown water headed for the local lakes and ponds... then think 2 more minutes about all the stone walled shorelines on the lakes and compare the amount of P coming from some guy's lawn or the cubic acres of soil and plant debris washing into the particular body of water at any given Spring or even rain events upstream...

    Common sense goes a long way to analyzing the physical world but the goal of greeners, is to distort reality to fit their political agenda... unfortunately there are enough gullible true believers that worship at the feet of 'education' that will always get up in your face if the topic is even breached...
    It's like a 'greenhouse' that cools for 16 years, even though there is no structural change that would cause a green house to not be overheating like it was the previous 16 years... common sense or the indoctrination of true believers??? it is all the same argument and not worth participating in...
    I can't be proven wrong so the personal attacks always are used to 'shout down the opposition' so to speak... :)
  3. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,159

    Can we leave your personal view of politics out of this discussion?

    I agree that leaves and other organic matter play a role in P pollution. There are also many other factors involved including: inadequate drainage systems, ever expanding areas of impervious surfaces, improper use of fertilizers.

    I do not think the current trend of banning P from lawn fertilizers will have any noticeable impact on our water quality. Once more people realize that, maybe we will concentrate more on coming up with meaningful solutions.

    Meanwhile, proper fertilization begins with soil testing and IMHO adding organic matter along with required nutrients.
  4. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I didn't put politics into the discussion,,, the gov't regulation has done that... and the reason why there can never be meaningful solutions is becuz the chicken little people will never allow a meaningful discussion about it... kind of like those who shout down the opposition at town hall meetings on the subject...

    Floods mean and do a LOT MORE than,,, " a role in P pollution"....
    That one point would begin a meaningful discussion about P pollution however,,, denying the HUGE impact of it,,, makes that meaningful discussion impossible...
    It will always be political, unless we put P in its proper perspective and include the contributing factors in accordance to ACTUAL impact...
  5. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,159

    Floods mean and do a LOT MORE than,,, " a role in P pollution"....

    Agreed, which is why I listed inadequate drainage systems, ever expanding areas of impervious surfaces. There have always been leaves falling to the ground, but they did not cause a water quality issue until we changed the surface of the earth within watershed boundaries.

    The other side of the story is that science, technology and the dreaded government are making strides in this area. The Feds & several States are beginning to make changes in our infrastructure which may reduce nutrient run off.
  6. Victorsaur

    Victorsaur LawnSite Member
    Messages: 81

    Hello axe, phasthound,

    I have to agree that there are many factors surrounding phosphorous pollution. The question is finding the availability of reactive phosphate rock in order to test its viability. The article states that RPR/DAP (diammonium phosphate) blends are what they are switching to. I've already tried to find Carolinian rock phosphate with the numbers as high as or higher than shown here: but I was not able to. For practical purposes, phosphorous with analysis less than 30% will be difficult to justify using.

    Barry, are you familiar with the listed tt / available phosphorous pentoxide, the range of %, and how that would translate to standard fertilizer percentages? (The link I gave for detail on RPR).
  7. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    Up here in Wisco we have thousands of lakes and streams and many of them have been filling in and becoming swamps, hundreds of miles from your manmade impervious surfaces... streams have become hundred year old drybeds that changed direction many time over the past several thousand years...
    Erosion is not a manmade phenomena, but we can and have really sped the process up in a variety of foolish ways...
    To say that lawn P is even significant in P pollution in our lakes right here,,, is laughable... leaving the OM in the shorelines is criminal...
    As humans we have the ability to undo natural and manmade damage to our lakes and streams and that is where a REAL discussion would be useful...

    Sorry Victorsaur, but analyzing the synferts chemical makeup is not a priority for me unless there is something that I can make a difference with... I think the ferts we have are just fine... :)
  8. Victorsaur

    Victorsaur LawnSite Member
    Messages: 81

    After looking into the matter a little more myself it has been difficult to find anything besides DAP (Diammonium phosphate) or super phosphate readily available. Apparently both come from organic sources and super phosphate is merely phosphate rock treated with sulfuric acid (no residue) to make it more soluble.

    Another interesting note from Rutgers:

    "There is no difference between an inorganic and organic phosphorus fertilizer source regarding phosphorus runoff losses. In fact, the application of either source to turf compared to no fertilizer has, in some research, reduced phosphorus losses in runoff. The reason for this it that the nitrogen applied with these sources of fertilizer helps to build vegetative cover of the soil, which improves water infiltration and reduces phosphorus runoff."
  9. turfmd101

    turfmd101 LawnSite Bronze Member
    Messages: 1,376

    18-46-0 DAP 50# 23,000 sq/ft 1# of P per 1000 sq/ft. or 46,000 sq/ft per 50# at 1/2 pound of P per 1,000 sq/ft. Each rate will turn your declining turf around.
  10. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I decided to try some Triple-10 garden fertilizer for the upcoming week, then just add some N in late Sept... Probably .5#/k for now or 5# of actual product per 1000 sq.ft.

    It will be interesting to see, since I've only done N ferts and Milorganite over the years... :)

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