CEC and Compaction

Discussion in 'Turf Renovation' started by Smallaxe, Mar 14, 2013.

  1. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,080

    As we read this article, can we assume that the "Flocculated" clay particles are the cation exchange sites???

    http://soils.missouri.edu/tutorial/page9.asp

    "... Aggregation begins with flocculation of clay particles (platelets) into microscopic clumps called floccules; the cations that are caught between two platelets attract the negative charges on both platelets, binding them together..."

    Is this the chemistry that makes humus/som/silt cation exchange sites???

    "... The polyvalent cations (including Ca2+, Fe3+ and Al3+) may also attract and bind with hydrophobic (water repelling) humus molecules allowing them to bind to clay surfaces. These clay-humus particles bind with each other and with grains of silt to form the smallest of the primary aggregates, perhaps as small as 0.01 mm. ..."

    Does this process help to access these aggregates for the roots as they endeavor to extract nutrients for the CE sites???

    "... As a soil dries out, the clay platelets move closer together and cause shrinking in soil volume. Cracks will form along tiny zones of weakness, and over the course of several wet/dry cycles this network of cracks becomes better defined. Plant roots, as they repeatedly remove water from the same vicinity, reinforce a drying pattern and contribute to physical aggregation of the soil. The process of freezing and thawing in the soil also contributes to the drying process as ice crystals form. And shrinking and swelling that results from wet-dry and freeze-thaw cycles creates tiny cracks or fissures (shrinking) and pressure (swelling) that break apart structureless masses of clay to eventually form soil peds or aggregates."
     
  2. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Your answer is NO to all the points/questions you presented.
     
  3. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,080

    You said earlier on a different thread that the CEC notations are meaningless on the Soil Test Results...

    Could you elaborate???
     
  4. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    No I didn't. I said CEC is highly variable, a comment in relation to the inaccurate information posted in that thread

     
  5. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,080

    OK, I mis-spoke,,,

    Perhaps you could explain to us the general principle about the chemistry of CEC in a soil in laymens' term that make sense to us...
    The many and sundry variables can be added later,,, I'm just curious where is the 'Starting Point', in which the interested LCO might find the info useful... otherwise there are no interested LCOs...
    And plz give a laymen's point of view, rather the a list of URLs...

    Thanks for any help you may be able to contribute... :)
     
  6. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    I already have on several occasions, and in threads you have participated in, why the need for the repetition, over and over again?

    A "simple" layman analogy I have posted before.



    Imagine a playground (soil) with 20 kids (solution ions), 5 of which are bullies. This playground has 10 swings (exchange sites).

    Everyone wants a swing, however the bullies always get them first (selectivity). So we have 10 swings with 10 kids (exchangeable ions) using them.

    Then a bus pulls up with 20 more bullies (fertilizer with irrigation), so now the 5 swings that could be used by the other kids get taken by the bullies (activity, concentration, selectivity). As a result, some of the kids leave the playground (leaching).

    Then a trailer pulls up with 40 portable swings (organic matter addition). Now there are enough swings to go around for everyone (increased buffering capacity).

    The above is an over simplification of a complex process, and doesn't take into account solubility, pH dependent charge and reactions, differences between cation and anion exchange, solvation, chelation, sieve action, etc... but you get the gist it.​
     
  7. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,080

    Thanks for that,,,

    Now we hear the fee-fi-foe-fum and the giant(root hair) is reaching in amongst the swinging kids and grabbing himself some snacks...
    Out in the open playground he's got plenty of room to get his wrist positioned for angling his fingers in order to grab the child he wants(soil structure)

    So we have the swings(colloids or exchange sites) evenly spaced about the playground in little groups of 3... inbetween one group there is a merry-go-round and another group(floccule) is over there beyond tether ball posts...

    When the truck comes in with more swings(CE sites), they for the forklift to unload the truck and the children climb onto them and pack themselves onto the thoses swings that do not move at all(platy structure) and the giant is only able to get a few of the chidren and ends up by-passing the majority of the truck and reaches for some more on the other side of the playground...

    Can the CEC accurately be measured as far as usefulness to the plant if all we count are the swings on the truck???
    My belief is that if you have compacted soils that the CEC is ONLY relevant to the point that the roots are able to feed... :)

    Also,,, Was the group of swings, portrayed as a floccule, an apt description in this context???
     
  8. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    I don't know what you just wrote as it makes no sense. Mass flow, diffusion, interception ..... look it up.
     
  9. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,080

    It makes no sense to you, because you may be over-thinking aspects that are NOT relevant to the subject matter...

    In starting with the "FLOCCULES" introduced in the article,,, the continuation of your analogy,,, makes perfect sense... When you understand the concepts of building soil structure which is the subject of the article then you'll see the picture of the giant's hand reaching into the truck where all the swing sets are packed together...
    If you can't see the problems with root hairs pushing their way through compacted clay,,, then you shouldn't be commenting on this article at all... the subject is compaction and how it relates to accessing CE sites... Perhaps you missed that because you seldom are able to connect up with what is ACTUALLY being discussed...
    So unless you are willing to discuss what this article is talking about, then you should have courtesy to to leave it alone...
    Your agenda becomes transparent when you say, * "... Mass flow, diffusion, interception ..... look it up. " * when the article is actually discussing those very things,,, only NOT in a way that's comfortable to you becuz you've NOT made the connection between what is written in the article and HOW that's related to your distraction...
    The subject of soil structure is so simple and yet you make it so far out and try to associate it with things irrelevant... you need to stop and think about what is really happening in the soil and its reaction to water,,, but you'll only "Fly Off The Handle", as it were,,, and demean, belittle, spew at, name call, and express every childish emotion that you can, sentence by sentence and ridicule the meaning of every line, becuz it DOESN'T fit into yourway of thinking...
    There's a reason WHY people don't think along the same lines you do,,, and that's becuz they can read a simple little article like the one presentted and make sense of it... and I'll never adapt your anti-rational, feelings based, psuedo-reality... so I'll be ignoring the rest of this thread as well...
     
  10. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    It makes no sense because it is nonsensical.

    Don't continue my analogy, especially when you do it incorrectly.

    Ummmmm, the subject of the article is "Soil Structure - Physical Properties". In case you missed it, it is in big bold font at the top.

    I didn't comment on the article, but rather your incorrect reproduction of it.

    Accessing by what?

    Again, I did not comment on the article.

    My "agenda" is providing people who browse this forum accurate and actionable information, something which you seem to care little about. But heh, since you feel relevance is important, why don't you speak on the percentage of nutrients obtaining by a plant root via exchange with a soils exchanger. Be sure to include references.

    I think you are talking about yourself again axe .... see above for example

    Try again, that is unless you speak for the whole of the scientific community and real industry professionals. Oh and FYI, I didn't read the article.
     

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