Watering Theory

Discussion in 'Pesticide & Herbicide Application' started by RAlmaroad, May 28, 2007.

  1. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    Mg is a secondary or Marco element of fertilizer and a SALT. Like all salts it is very Hygroscopic or attracts water. The Mg is call Adsorbent and the the hydra film is that water that coats the Mg molecule which is then called Adsorbate. To release the water or Hydra film the process is call desorption. This chemically differs from water up take by Plants which is absorption. IMHO Mg doesn't have enough Hydraulic conductivity to be of value to increase field capacity. But what do I know?

    BTW Mg is used as a drying agent in some cases.
  2. txgrassguy

    txgrassguy LawnSite Gold Member
    Messages: 3,083

    Ric, I believe what the Isreals were getting at was altering the hydraulic conductivity and permeability by effecting the base CEC of the soil profile.
    The idea being that an absorbant acts like an anion, will affect the valiance of the soil, with the idea being that with more "readily" available water, additional micronutrient input wouldn't be as necessary as leaching potential has been addressed by the Mg.
    Bear in mind the predominant soil structure is primarily calcarious sand, highly affected by leachates, and some temporary buffering and hydraulic conductivity was observed by the escalation of Mg levels which was extrapolated to infer greater amounts of absorbates.
    Additionally, this study was under taken to address the efficacy of additional amounts of Mg towards increasing crop yields which differs significantly from turfgrass maintenance practices.
    Just my 2cents though.
  3. JoeinJasper

    JoeinJasper LawnSite Member
    Messages: 173

    Thanks...Since its been a few years since I had any agronomy classes...As I understand you to say- There is such a narrow window for the proper conditions there is no practical benefit to this practice. But when dealing with both fescue and bermuda in the transition zone does this practice cause fungus to spread as we were once taught, or are these recommendations based on adherence to water restrictions?
  4. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    If anything Mg is going to help eliminate Fungus not cause it. Macozeb (a now ban) Fungicide was in fact Mg and Zinc. Of course it was ban because it was cheap and worked great.


    Where I don't follow you is on changing the valiance of the soil. The element Mg2+ would do that, but Mg sulfate which is the most common form for use in agronomy, and is in fact a balanced compound. I understand the theory, because it is the same as using synthetic glass beads to increase both CEC and Hydraulic conductivity.
  5. txgrassguy

    txgrassguy LawnSite Gold Member
    Messages: 3,083

    Joe, depending upon your existent soil conditions, excessive Mg is in fact a deteriment.
    Essentially what happens is the exchange sites are "full" and leaching of more desirable micro and macro nutrients occur as there are no exchange sites available on the soil particle.
    Admittedly a simple explanation yet after 3 + too many malted beverages this evening my mind may not be working correctly.

    Ric, as I understand the study conducted by the Isreal's, it focused on elemental Mg.
    The idea of altering the valiance of the soil comes into play when utilizing mostly IBDU forms of nitrogen in order to effect even more of a controlled, sustainable release.
    I really cannot be more specific as it has been over fifteen years since this was discussed and I can't say - with a straight face anyways - that soil chemistry was a particularly fond subject of mine.
  6. Again, a firm believer in watering deeply but infrequently! This applys to all soils, but the time it takes to reach the bottom of the rootrone in a sandy soil will be much less than a clay or silt soil. Also remember, the interval between watering will be much less with a sandy soil.

    Cool season turfgrass generally have 80% of the roots in the top 3"of the soil.

    Golf course watering...just don't have much choice but to water at night when golfers not pressent....General supt will water the highest quality turfgrass ( putting greens) in the very late morning hours, completing just ahead of maintenance crew
  7. hughmcjr

    hughmcjr LawnSite Member
    from Oregon
    Messages: 183

    ^^ Interesting. I was just going to say here in Oregon where we have clay soil, I recommend watering 20 minutes per day for two days on and then two days no water. For example, Mon., Tues. water, Wed., Thurs. off. Back to back then let the roots reach. I get excellent results. Many people think watering every other day for 15 minutes or every day for 10 minutes is good, but actually the 15 minutes a day isn't enough from June through Sept as it is so dry. Watering everyday for 10 minutes I have actually seen many lawns turn brown anyway so water is wasted and the grass is brown.
  8. Nobletoad

    Nobletoad LawnSite Member
    Messages: 8

    I have to vigorously disagree. the moisture manager product in Lesco's Ecosential line is no gimmick. It does contain a surfactant, but in addition it uses a product called Hydretain which is well-known and proven to pull moisture vapor out of the air in the soil and keep it from evaporating up and away. Instead it traps the moisture in the soil where roots can use it. I've seen demos that their reps do where the raw material (a dry white powder) is placed on a counter top and within a few minutes the powder is gone and a puddle of water is in its place. It literally draws humidity out of the air. We've used it with great success and it keeps turf and containerized plants happier between waterings and has the dual effect of preventing the soil from becoming hydrophobic between our irrigation cycles which is super important now that we are on watering restrictions. :eek:

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