he says this fertilizer is "CRAP"

Discussion in 'Fertilizer Application' started by americanlawn, Jun 14, 2018.

  1. Delmarva Keith

    Delmarva Keith LawnSite Senior Member
    Messages: 493

    To put a finer point on it, same thing happens at low ph — actually it’s worse at low ph; P combines with primarily iron and aluminum at low ph and with calcium at high ph. Another problem with high ph is additional P release from naturally occurring or applied rock phosphates in the soil which can then go on to fixate with the noted nutrients and create sort of a vicious circle. At any ph, P can fixate with plant nutrients (somewhere between 70 and 90% of phosphate fixates just about the moment it hits the ground — the lowest P fixation does occur at ph just below 7.0 but still a very significant percentage) and as a result, hyper-excessive P can cause deficiencies.

    So that’s sort of where we are with excessive P.

    Now to turn to ph, if you see iron deficiencies at high ph, it’s likely not caused by P fixation (unless P is ridiculously excessive as noted above). Iron readily oxidizes in high ph soil, converting to the ferric form which is not plant available. Maybe you meant low ph? — P fixates strongly with iron and is basically completely insoluble in very low ph soil (like 4.0).
    Last edited: Jun 20, 2018
    hort101 likes this.
  2. greenfire

    greenfire LawnSite Senior Member
    Messages: 387

    Are you familiar with "ALL N" by TCS? Does this contain DCD?
  3. Eric Miltner

    Eric Miltner Sponsor
    Messages: 53

    I am not familiar with that product. I would suggest you search TCS's website which has an extensive list of their products.
  4. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Messages: 9,844

    Controlled release N, whatever form that may be, behaves just like straight urea during typical summertime weather. In other words, it don't do crap. Only time I would put down crn, rxn, nutrisphere, etc would be late fall when breakdown of N is slow to nil.
  5. Eric Miltner

    Eric Miltner Sponsor
    Messages: 53

    You may be confusing CRN (Controlled-Release Nitrogen) with Stabilized Nitrogen. The two animals are completely different. Confusion may stem from inaccurate labeling (as in the product first discussed in this thread) or from inaccurate info from other sources.

    CRN refers to coated products, primarily polymer coated urea (PCU). The other products you mentioned above are not CRN or PCUs, they are forms of stabilized nitrogen.

    CRN works by protecting urea with a polymer coating. Nitrogen is released slowly, diffusing across the polymer membrane. CRN products do release nutrients more quickly under warmer temperatures versus cooler, but the mechanism is still slow and controlled.

    Stabilized N works by introducing additives to urea that impact how the urea is broken down in the soil. Some stabilized products have only one additive, a urease inhibitor (usually NBPT), which limits N loss due to ammonia volatilization. NBPT does not significantly change the longevity of N availability (it does not act like slow-release). Some stabilized products contain another additive, a nitrification inhibitor (usually DCD), which helps retain N in the ammonium (NH4+) form, rather than it converting to nitrate (NO3-). Ammonium can be held on soil exchange sites, extending how long N is available (acts like a slow release).

    For products with NBPT only, you may not visually see the results, but N loss due to volatilization should be reduced. This is good, becuase more N can get into the plant. If you are expecting extended N response form Stabilized N, make sure your product contains the nitrification inhibitor DCD. Read the label, and ask your supplier. In addition, it needs to contain enough DCD to do the job. If the DCD was added by spraying it in the surface of the urea, there is probabaly not enough there to help much. Again, ask your supplier.

    CRN (PCU) will result in extended N availability compared to regular urea to regardless of the season. These products are available in various longevities, so match the product to your needs. There are products available that will allow you to fertilize as little as one time per year when used correctly.

    You can find a lot more general educational information on various fertilizer technologies at Kochturf.com. This is not a sales pitch. There are just not a lot of resources out there that explain how all these different technologies work. This knowledge is critical in using products correctly, and getting the results you expect. It's hard to dig up a sprinkler head with a popsicle stick.
  6. sprayboy

    sprayboy LawnSite Senior Member
    from Indiana
    Messages: 998

    So what are you putting down in the summer? Straight urea?
  7. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Messages: 9,844

    No, would not touch stabilized N during the hot months. Use poly coat urea.
    I apologize, yes I was referring to stabilized N in my post above.
  8. Eric Miltner

    Eric Miltner Sponsor
    Messages: 53

    Just one more note. If you use Stabilized N, the stabilizers that are added to the urea do not change the salt index of the fertilizer (the biggest determining factor in "burn"). In other words, it does not change the burn potential of urea. So apply as you would straight urea. It is ok to use Stabilized N in summer, you just have to be a little more cautious. Under summer conditions, I would recommend relatively low rates (0.75 lb N/1000 or less) and water volumes of 2 gal/1000 or higher if spraying. And water-in if possible.

    As noted above though, polymer coated or polymer-coated-sulfur-coated urea is an excellent choice for summer.
    greenfire and Delmarva Keith like this.
  9. Delmarva Keith

    Delmarva Keith LawnSite Senior Member
    Messages: 493

    Yes, sufficient water after application is very important detail (don’t ask me how I know that) :).
  10. Dan Lee

    Dan Lee LawnSite Member
    Messages: 1

    Perhaps spread it using an over-lap and then cross ways to ensure that all lawn areas are covered? Just saying. Also, does the mfgr say it is a homogenous blend? If it is not homogenized then the prills may be inconsistent and cause streaks. Homogenous means the nutrients are completely consistent with each prill. Thats good.

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