Confused about when to fertilize

Discussion in 'Fertilizer Application' started by Victorsaur, Jun 21, 2013.

  1. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,162

    Did she give you any explanation as to how this happens?
  2. turfmd101

    turfmd101 LawnSite Bronze Member
    Messages: 1,376

    I was discussing with Lee in mid 2010, that since 2007 when Lesco started blending P free ratios (2-0-1's). (Lesco was always the for front of compliance.) I had been studying an average of 12 soil sample results per week from all areas of central FL sent back to me from CLC labs in Ohio. Prior to 2007 P was always surplus guaranteed it was a given. From 2007 to 2010 I saw a trend that ended with P showing LOW consistently. Mostly sandy soils. I was always told it was locked up and not available for plant uptake. Not what I saw. In 2007 to current year Fl weather is only record breaking not normal. Its either, record rain, record drought or record cold. One to the other and the other to the one. Turf grass is suffering and not only slow but hard to recover. Turf damaging pest (not just BUGS) cause more severe damage. In early 2010 I introduced 18-46-0 (DAP) to my customers. I have always been a promoter of 0-0-62 frequently when poor conditions are present and my favorite blends 5-10-31 w/10%Fe & 9-2-24 w/6%FE 2%Mn 2%Mg. both SOP. My customers took 18-46-0 to their most troubled lawns they had been fighting since 2009 and had a rapid complete recovery. Not only recovered but the continual record changing conditions caused little effect. No stress no chinch no fung no stress. They were and are believers. I was even told by my superiors and piers that blend was stupid, not worth blending (because I was the only one ordering it in Fl). It was because of low margins but results mattered to me more. Im a Nature Mechanic. Shortly before I left in Late 2010. Lee mentioned to me after our discussion about my studies that an intern at UF was studying milorganites possibility to free locked P from the soil and initial results were promising. I left Lesco and never got to follow up. I passed this on to my customers and I still consult with most. They still follow my blend recommendations and have more powerful lawns and agree strong heart idly with my program. They would not call me 3 years later to always say thanks if not. I wish I knew the UF results I have not followed because I just always believed. I do know it took a lot of milorganite and a long time to break out P. So I went for (DAP). Typing is not my best way of expression. Feel free to call. 407-580-2314. I'm not shy. My vocals are much more expressive than my keyboard fingers. :drinkup:
  3. foreplease

    foreplease LawnSite Silver Member
    Messages: 2,062

    Thanks Skipster and turfmd101 for your most generous and intelligent discourse!
  4. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I concur... If I've had a misconception about AMF it is good to know that...

    The How and Why Milorganite is able to free bound up P would be an interestting process to know about as well...
  5. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082
    "... The influence of different forms of P present in soils on the availability and uptake of P from natural and fertilizer sources remains the subject of active research (B√ľnemann et al., 2011). It is generally accepted that AM and NM plants access the same forms of inorganic soil P, including P that is reversibly adsorbed to various soil minerals and exchanges with the soil solution (Marschner, 1995; Frossard et al., 2011). Many AM plants can acquire more total P than NM plants from the same soil, which is thought to involve increased spatial exploitation by hyphae in soil (Marschner, 1995). The competition for P in soil between AM fungal hyphae and roots has already been raised as a possible explanation for reduced uptake via the direct pathway, but it is hard to accept in situations where plants are poorly colonized and root and hyphal length densities are low."

    That paragraph agrees with your point, but notice from the following,,, it does not stop there... So let me rephrase the question about soil tests... Does the test report "poorly available P" or "organic P", as is refernced in the following statements???
    If all bases are covered and the test is for turf,,, with an understanding that it is likely AM innoculated(naturally) then perhaps there are P deficient soils,,, especially,,, on lawns that bag...

    "... Positive mycorrhizal growth responses can increase if poorly available P is applied to soil, even for plants that show little or no positive response at low P. This finding shows that AM plants can access poorly available P more effectively than NM plants, but the mechanisms by which they do so are not well understood (Bolan, 1991). There is some evidence that AM fungi can exploit sources of organic P in soils, but the quantitative contribution of this process to the supply of P to plants is probably small (Joner et al., 2000). Higher exploitation of poorly available soil P by AM plants is increasingly important in the contexts of understanding AM responsiveness and the utilization of poor-quality fertilizer sources. All these uncertainties require investigation if we are to understand the soil-AM plant continuum relating to P uptake. "
  6. ruchtisprayer

    ruchtisprayer LawnSite Member
    Messages: 1

    one important thing, is to use a low nitrogen fertilizer during warmer weather. its one of the main things brown patch, and fairy wing diseases feed on.
  7. Victorsaur

    Victorsaur LawnSite Member
    Messages: 81

    Great to see this thread turning into a good discussion. An article written by NCSU (NC State) states that :

    Phosphorus and calcium move very slowly through the soil profile so to be most effective they should be incorporated into the top 6 to 10 inches. These elements can be surface applied but the nutrients will not be as readily available to the plants and will be less effective. 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 P505 per 1000 sq. feet. For soil incorporation of phosphorus, triple superphosphate (0-46-0) is recommended. For 1 to 2 lbs of P505, incorporate 2 to 4 lbs of triple superphosphate per 1000 fe of bed area. Diammonium phosphate (18-46-0 or 16-48-0) is the most soluble phosphorus source and should be used if phosphorus is applied to the surface. For 1 to 2 lbs P205, apply 2 to 4 lbs ofdiammonium phosphate per 1000 ft2 of bed area. This will also supply 0.4 to 0.8 lbs of nitrogen per 1000 sq. feet.

    So the argument remains that what this article states is innacurate given that there is already a lot of P available in the soil? Perhaps it varies from soil to soil? The "Tree Doctor" who has been working for huge businesses like the Biltmore estate also says that soils around here are so naturally devoid of Phosphorous that they can usually be amended with a granular application, particularly DAP, but it can take some years to take an effect on the soil.
  8. turfmd101

    turfmd101 LawnSite Bronze Member
    Messages: 1,376

    Thanks for all the article quotes. I've never read a study. I believe we will be switching from annuals to perennials for food crop production so the food crops can continue to grow their roots deep enough as to tap into the nutrients deeper in the soil and so we stop erosion of the surface soil and continually depleting surface nutrients we have to continually replace with additional nutrients. Which is over fertilization. The majority reason for run off.
    Last edited: Jul 13, 2013

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