Flaws of super phosphate

Discussion in 'Fertilizer Application' started by Victorsaur, Nov 9, 2013.

  1. Victorsaur

    Victorsaur LawnSite Member
    Posts: 81

  2. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,938

    Applying too much phosphorus, irregardless of source is not wise. Triple superphosphate simply made it cheaper and easier to do so. I get sky high P levels on a regular basis due to past misuse of 16-15-15, 10-30-10 or 10-20-20 AG fertilizers on lawns and landscapes. That does create the micronutrient deficiencies described in that link. Do not get the idea that adding micronutrients to the soil will fix the problem. High phosphorus levels in the plant tissues themselves bind to the micronutrients no matter how much is applied to the soil. What is applied in granules with micronutrients added is a fraction of the actual need. Do you know of any granule applying the equivalent of 1 lb ferrous sulfate and 4 oz zinc sulfate at label recommended rates. Those granules are ok for maintenance of areas where there are no problems. Not so much for deficiencies and imbalances.
     
  3. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,532

    For the most part P is largely banned around here. Misplaced blame led to that.
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  4. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,938

    Has the source of P pollution in Florida been determined by a disinterested party? I think making grass starve and thin out during the wet season is hardly a way to prevent pollution. Hawaii is a little smarter. The regulators go after soil runoff entering waterways. That's right. Construction sites of any size must not allow dirt to run. There is a requirement to maintain vegetation on errodable slopes. Inspectors will respond to any reports of soil running down drains.
     
  5. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,532

    I believe so. A new house is going up across the street and the first thing in was the plastic dam and haybales around the storm drain.
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  6. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,938

    So what is the difference between excavated ground and a lawn so thin from starvation that the soil washes out? Arbitrary bans on fertilization are counterproductive.
     
  7. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,532

    Any suggestions for a substitution? I know its been largely overdone in some spots, but I'm sure some areas are truly deficient.
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  8. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,938

    Lift the bans. No substitute for N and P. I can see harm in feeding K only in isolation as is mandated by Florida laws. Remember that K and Na are not that far apart.
     
  9. Victorsaur

    Victorsaur LawnSite Member
    Posts: 81

    So GD, would you know of any alternatives to super phosphate besides DAP or what would you recommend? If I understand you correctly it doesn't matter what source the P comes from for the most part as it bonds (at a molecular level?). Another thing about phosphorous is the the issue of its' permeability, especially in clay or compacted soils, which is why I'm guessing I don't see many people going with the larger rock phosphate on established lawns. It seems like guano is a viable organic alternative. Thanks again for your valuable input and knowledge on these subjects.
     
  10. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,938

    I like MKP or else 0-60-20. Both are soluble. There is some soil bypass if applied foliar. 0-60-20 will also chelate micronutrients because when placed in water, it turns into phosphoric acid and potassium phosphate. Neither of those are to be applied unless soil testing, tissue testing, and/or visual symptoms demonstrate need. I am from the school of spoon feeding. Do not believe in huge applications of fertilizer a handful of time per year. Would never work in my area. 12 month growing season.
     

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