PH Ruminations.

Discussion in 'Organic Lawn Care' started by Organic a go go, Jan 14, 2008.

  1. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    If we keep our feet firmly planted on the ground and look at this.

    In an environment where my company or golf course is on a typical fertilizer, pesticide, regiment PH is something I need to track as it is the only way that these chemicals will be available to the plant and I will need to adjust the PH to make them available. albeit fertilizers are plant available in a wide range of PH, I still need to make sure they the soil does not move too alkaline or acid because the turf likes a slightly acidic environment to grow in. Its been done for a long time with good to great results.

    If you move to sustainable ways (this IS the organic lawn care forum) to take care of turf do we still have to monitor PH, sure but as a tool in our arsenal of tools. As a car mechanic do I use my allen wrench set every day, probably not but its nice to have when I need it.

    Gerry's quote from Elaine brings a couple things to light. For over 450,000,000 years (or more) plants have set up the capability to grow in the soil and work in conjunction with what is around them. Plants have places in their roots where they exude, carbohydrates, sugars and proteins (exudate's). Different plants exude different "flavors" or combinations of these substances. They all exude these flavors and attract different types of beneficial microorganisms. The types of beneficial microorganisms that they attract are plant dependent, in some cases the plant may be lacking in some nutrient and will exude a protein to attract a certain type of beneficial to supply the nutrient lacking. I am not saying that plants can think, it is just that they have been doing this for a long time and kind of have it figured out by now.

    This symbiotic relationship is happening right next to the root of the plant, as the plant grows and the roots reach deeper into the soil the "beneficials" follow and literally coat the root and the area around it with bacteria, fungi, protozoa, nematodes, etc. This is almost a living cocoon encasing the plant root. Guess what types of beneficial a plant attracts? the kind that it likes and the kind that make the environment around the root beneficial to the host. The most fertile place in the soil is at the tip of a root

    But wait a minute!!!! who is adjusting the PH??? don't we need someone to adjust the PH so all of this will be OK??? is it the the lawn guy putting down lime making all of this happen??? I don't think so.

    The plant and the beneficial microorganisms are the ones controlling which input is eaten or left alone and which output is provided to the soil and plant root. This area around the root where all of this happens is determined by the availability of nutrients and organic matter. There maybe all kinds of food in the soil but is it the right food to support the types of beneficials your are trying to promote. The turf appreciates a bacteria to fungi ratio of about 1 to 1, often a little more bacterial (around here because the soil is slightly acidic).

    What is that telling me? as Elaine said in Gerry's post,

    "Aerobic bacteria make alkaline glues, slimes and waste products. They push soil alkaline, to the point that nitrifying bacteria will do the job of converting ammonium to nitrate. But remember, when nitrifying bacteria make nitrate, they merely remove the hydrogens from the N, and replace them with oxygen. The bacteria do not take up that inorganic form of N. They only do an oxidation - reduction reaction. They take a mineral form of N and convert it to another mineral form of N."
    So the bacteria push the soil slightly alkaline and make a food source for the nitrifying bacteria which keeps the balance, so simple its wonderful.

    I told you I could go on and on, done for now though
  2. Tim Wilson

    Tim Wilson LawnSite Senior Member
    Messages: 795

    I think you have expressed/interpreted this fairly well. It's interesting that a similar discussion is on the compost tea forum. It has been my experience that microbial amendments do 'self-regulate pH over time in test beds. Tim
  3. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,335

    I want to add that we need to be careful not to look to closely at one particular factor of the system. While biology (in particular biology found in the rhizosphere as Bill pointed out) plays a very important role, we need to understand how that biology fits into the entire system.

    Considering water is the primary driving factor of any biological system, we look at how water relates to and moves through that system in order to gain a better understanding of the system as a whole, or in this particular case, plants & nutrients. This relationship (or pathway) is known as the Soil-Plant-Atmosphere Continuum (SPAC) and it involves several scientific disciplines.

    So I guess what I am trying to say is try not to look too closely at any one particular part of the system, like pH, and attempt to manipulate only that part of the system without understanding how it fits and works with all the other parts of the system.
  4. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    Good point, these are systems and we do need to keep our distance and look at the entire matrix of events that are going on. I was trying to explain why not to chase PH and the reasoning behind it.

    Tim, You caught me red handed, that was me that started that thread. Who better to ask than the people that have been doing it for 20 or 30 years. I was trying to get some clarification on a subject I had not commented on for some time.
    Elaines comment was: "The "old pH and nutrient availability charts" ignore the effect of microorganisms in the soil. In fact, I'm fairly certain that the research done to show the changes in nutrient availability had to have been done in soil that were so hammered biologically that there was, essentially, no biology present in the "soil". So of course, it wasn't actually soil that they used to do those studies. " But DIRT (my comment)
  5. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,335

    I would agree with that. Those charts largely show the chemical relationships between pH and the mineral fraction of the soil, so with respect to that, the chart is still useful as a field diagnostics tool. However as pointed out, biological activity and other factors of the system can alter those relationships drastically, so once again, we need to keep the big picture in our minds eye. :)

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