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paperdesk

Soil Test, Silt vs. Sand!

paperdesk
14 years ago

I was recomended by kimmsr to do a simple test to determine the composition of my soil.

I put a line 4 inches from the bottom of a quart jar, and filled up to that line with garden soil from two different parts of the garden. I filled the jars with water, shook them up and let them sit for about 2 days.
{{gwi:270605}}From Garden Soil

Sample 1. This is from the garden plot we have been using for 4 years. We've added several inches of composted manure over the years, and last year I dusted it with activated charcoal.
{{gwi:270606}}From Garden Soil

Sample 2. A garden spot we started using last year for the first time. We only added a trace of composted manure and nothing else.
{{gwi:270607}}From Garden Soil
{{gwi:270608}}From Garden Soil

Both samples have a lot of sand or silt on the bottom, and virtually nothing else apart from the oraganic matter floating on top. I cannot tell if large layer on the bottom is silt or if it's sand. I'm posting photos in hopes someone can help me out. Also I find it is interesting to see that one jar has clear water and one doesn't.

Ted

Comments (26)

  • Laurel Zito
    14 years ago

    I try to think did a river run through where your house is located or are you located near the ocean like myself?

  • docgipe
    14 years ago

    Here are the basics that you are sure not finding in your soil structure. My comments are based on a 1000 sq. ft. patch. Starting in early fall add a pick up truck heaping load of manure. That will be about three inches over all. Add a truck load of leaves. Till this in with twenty pounds of organic low number fertilizer like 4-2-4, ten pounds of Ironite for trace minerals and lime based on a soil test need to work towards a goal of a PH 7. Rake this roughly and seed with five or six pounds of rye grass.

    Very early in the Spring add another half load of manure, twenty more pounds of low number organic fertilizer, ten more pounds of Ironite and till everything into the soil to make a seed bed. Save the lime additive for fall applications.

    This is serious soil building. Do this for three years. Your organic content should be ten percent or better, The tilth will be excellent. After the third year cut your manure to half a pick up truck load but maintain all other additives. You may wish to have another soil test at this point but I doubt it will be of much value. You will already have built one of the finest gardens in your area.

    If you care to make it as good as it can be consider and use Mycorrhizae.

    Any compost you happen to have or care to make will support the total but your whole garden should be in very good condition with just tons of worms working and becoming more in number each year.

    There is just no better way to arrive with healthy soil and happy healthy plants.

  • paperdesk
    Original Author
    14 years ago

    @Tropical_thought

    I am on top of a hill with vallies all around, however we are right next to the Columbia river, so it is feasible that many years ago the area property was part of the river.

  • paperdesk
    Original Author
    14 years ago

    Docgipe

    Thank you for weighing in on this! Sounds like you are onto something that has worked really well.

    I just realized I mixed up my photos! My description of sample one should go with the photos for sample 2 and vice versa. Wow, I can't believe I did that.

    I have added a lot of composted manure in the last couple of years to sample 1, but not sample 2. I'm not sure if you were referring to both or not in your suggestion.

    I'm a little dubious about the whole heavy metal thing in regard to Ironite, but I'm not going to discount it's use for others based on my very minimal understanding. I just don't feel comfortable myself.

  • gargwarb
    14 years ago

    In your jars there, it's tough to tell how much sand, silt and clay you have. Ideally, the sand will settle out first (bottom layer), then the silt (middle layer), and finally clay (top layer). Of course, some of the smallest clay particles will remain in suspension for a long time and won't end up as part of the "clay" layer. That, along with some organic material, is why it stays a little cloudy.

    One important step that often gets skipped in a jar test is to add calgon or table salt before mixing. Those materials will keep clay particles from sticking together. If you don't add something to get the clay particles to deflocculate (sorry, Dan) they will stick together and form clumps. Those clumps will settle out with the sand and silt particles, which makes it look like you have more sand and/or silt than you really do and less clay than you really do.

    By the way, a three inch layer of manure over 1000 square feet would be roughly 9.3 cubic yards of manure. You better have a pretty big truck. ;) If you use a regular pick up truck load, it will be about 1 cubic yard or so.
    I would hold off on adding any fertilizers until you know if you need them or not. You might already be sufficient and the manure will provide some of those nutrients.
    I also share your concerns in regards to ironite.

  • paperdesk
    Original Author
    14 years ago

    @Gargwarb.
    I didn't know about the salt, how much do you use?

  • gargwarb
    14 years ago

    About a teaspoon or so should do the trick.

  • Laurel Zito
    14 years ago

    I guess you have silt then, but of course, deserts have sand. I have wondered if my small grain sand is just like silt then the treatment would be the same for each case? It would not be be so important to know if was sand or silt as long as one knew the proper treatment for soil reformation if the treatment was identical. Besides organics I added small amounts of clay and large grained horticultural sand, but not very much, because I don't know if I am doing the right thing. You can buy the sand from in a cactus planting mix or sometimes they just sell sand for people to mix their own mixes for planting cactus. I had decided to try some succulent plants, but the plants didn't do very well in my climate, which is why I added the sand.

  • ericwi
    14 years ago

    You are on a hill near the Columbia River. I suspect that you can see two or three volcanoes, on a clear day. You might have soil that contains significant volcanic ash. It might have pH below 7. On the other hand, your garden site could have been subject to soil erosion, given its location, and the topsoil might be gone. Do you have trees, flowers, grass, or vegetables growing in your yard?

  • Kimmsr
    14 years ago

    As described in the written part of the simple soil tests the heaviest soils particle, sand will settle on the bottom. Since silt is smaller and lighter and clay is smaller and lighter yet they settle above that. Now if your soil does not have one or another of those soil mineral particles they will not settle out so maybe, possibly if your soil is clay (Most of the soil tests I have done in Indiana and Ohio are only clay, no sand or silt) that is all there will be. When I test here I get nothing but sand and organic matter.
    While it might be good to know for sure just what the mineral portion of your soil is, how much of each type is there, the most important part of that test is organic matter, the stuff on the top of everything else. Very few will get an optimal results, ie. 45 percent sand, 25 percent silt, 25 percent clay, and 5 percent organic matter because that will only be where the soil is loam.
    Since I have no idea where in the United States you are and the pictures of the jars are very small it is difficult to say for sure what is there. Adding salt or a water softening substance is not necessary and in fact can skew the results.

  • piedmontnc
    14 years ago

    Since I have no idea where in the United States you are and the pictures of the jars are very small it is difficult to say for sure what is there. Adding salt or a water softening substance is not necessary and in fact can skew the results.

    WHAT???

    The whole point of the salt/water softener is to keep the clay dispersed so you DO get an accurate picture.

  • gargwarb
    14 years ago

    (Most of the soil tests I have done in Indiana and Ohio are only clay, no sand or silt) that is all there will be. When I test here I get nothing but sand and organic matter.

    I would guess that you're not seeing any layers because you're not adding anything to disperse the particles, resulting in precisely the problems I've described above.

    Also consider this. If adding a deflocculating agent skewed the results, it probably wouldn't be a integral part of both USDA and ASTM methodology for soil texture analysis.

  • idaho_gardener
    14 years ago

    Please do not use Ironite in your soil. It contains lead and arsenic. I have surfed over to the Ironite company's web site and look at the various products to see how much toxic metals they contain. Do the same before using Ironite.

  • Laurel Zito
    14 years ago

    I found a simple test for clay. After a heavy rain, if you can pick up a clunk of soil and begin to make a clay rabbit with long ears and it all stays together to make the rabbit ears that is clay. So, it's easy to tell if you have clay, if you don't it's sand or silt and I think the treatment for both being the same or similar you can go from there.

  • docgipe
    14 years ago

    It is indeed a sad day when the issues in California can and have spread worthlessly through the internet's social sites including this one. Most if not all other state's have ignored California's stance against Ironite. My state Pennsylvania threw the case out of court. Reason: Very simple the true claims were insignificant. For instance the claimed problems were almost immeasurable. Other sources of the same contents were far more significant while causing no proven problems.

    There are other trace mineral sources. Azromite, greensand either Eastern or Texas variety, granite dust.

    If you are in the Mt. Hood fallout area you may have many of the elements in Ironite or other trace mineral sources. Incidentally I did test Mt. Hood fall out and found the items challenged in Ironite. I saw the recovery areas both in an outside the fallout patterns. The fallout areas recovery were then and are now impressive over areas that did not get the fallout. The test materials were collected personally. The garden got all two pounds of it I drug home just to play with.

    Those Ironite questions are totally insignificant except in California. This relates more to political baloney than agricultural biology or science.

    The only reason I mention Ironite is that it is easy to find and use in most states except California. If you still have reserve use any one of the remaining trace element sources. There are I believe 67 known trace elements. Very few if any will show on any soil test that an average gardener would purchase.

  • gargwarb
    14 years ago

    I understand where you're comming from docgipe, I really do. I tend to go off the handle a bit when I see fear mongering based on hearsay. It discredits the whole organic movement.
    However, the jury is still out on Ironite.

    From the EPA:
    "Earlier research sponsored by the producer of Ironite® identified the arsenic-bearing phase as arsenopyrite, with the conclusion that arsenic in that form does not pose an ecological threat. However, a closer look with Extended X-ray Absorption Fine Structure (EXAFS) has concluded the arsenic phase within Ironite® to be scorodite-like. Scorodite is more soluble than arsenopyrite; in fact, the dissolved arsenic released from scorodite can exceed the U.S. standards for drinking water. In addition to the data collected at Argonne National Labs in February 2005 that identified arsenate sorbed to iron oxides as the dominant arsenic bearing phase, secondary identification techniques are being used to confirm this finding such as thermogravimetric analysis and Mössbauer spectroscopy."

    How likely is it that is arsenic going to leach into the groundwater? Nobody's sure yet. They're still looking into it.
    If it does, how likely is it that enough will be applied to be problematic? Or, is it virtually nothing at the end of the day? That hasn't been studied yet either. The lack of information is reasonable cause for cautious concern.

    If Ironite was the only game in town, then I just might say to go ahead and use it but, as you noted, there are plenty of alternatives that don't have the same issues.

  • Kimmsr
    14 years ago

    When you are testing your soil you should not want to have the various soil particles to remain dispersed in solution if you are interested in knowing the percentage of clay in that soil. Where I have tested the soils in Indiana and Ohio there is no sand, however if I were to get closer to Lake Michigan or Lake Erie there would be sand in the soil and the closer I would get the greater the amount of sand I would find.
    As I stated adding a water softener or soap to that soil test is not necessary and could give skewed results.

  • gargwarb
    14 years ago

    When you are testing your soil you should not want to have the various soil particles to remain dispersed in solution if you are interested in knowing the percentage of clay in that soil.

    From the best I can tell, that statement came from outer space; somewhere in the gamma quadrant of Centaurus A, if I'm not mistaken. It's a place where the local inhabitants have replaced the study of physics with a bi-monthly "pull my finger" tournament.

    Honestly, I have no idea how to respond to that comment. It's like trying to explain that one plus one equals two, rather than seventy four and a half. It really is a very simple concept and if you truly need an explanation, do read my first post in this thread again.

  • piedmontnc
    14 years ago

    When you are testing your soil you should not want to have the various soil particles to remain dispersed in solution if you are interested in knowing the percentage of clay in that soil. ...As I stated adding a water softener or soap to that soil test is not necessary and could give skewed results.

    You sir, do not know what you are talking about.

    The salt/softener is not to keep the clay in solution but to keep it from flocculating so it does not form larger aggregates which settle out with the sand and the silt (see Stokes law of settling), which if it does settle out with the sand and silt DOES SKEW the results. Dispersing the clay first gives ACCURATE results.

    What part of that is so hard to understand?

  • Lloyd
    14 years ago

    I've said it before, I'll say it again, one of the first steps for getting out of a hole is to stop digging.

    Lloyd

  • rott
    14 years ago

    ..
    Learning a lot here. Thanks for the inputs from ALL on this thread.

    Arsenic - strikes me as ubiquitous from the get-go. How much is too much? I would think I'd have more to worry about from all the crud the sub urban traffic spreads just outside my house. I can hear the freeway at night.

    How different is flocculating clay from sand?

    When testing something, isn't it counter-intuitive to introduce additional ingredients?

    I'd look some things up but from the discussion, I'm not sure what exactly to start searching on. If anyone wants to feed me keywords or just get into the details, I'd really really appreciate it.

    Thanks in advance
    ..

  • piedmontnc
    14 years ago

    How different is flocculating clay from sand?

    It's still clay, in that it's a chemically reactive surface whereas sand isn't. The only difference between flocculated clay and unflocculated clay is that the clay will settle out with the sand and silt mineral fractions skewing your results if you do a settling test.

    When testing something, isn't it counter-intuitive to introduce additional ingredients?

    Depends on what you're trying to accomplish with the test, in this case, the dispersing agent remains dissolved in the water and only affects the results by giving you a more correct reading of your clay composition.

    Personally I skip the jar test since I can classify texture by the ribbon method

    http://www.mt.nrcs.usda.gov/about/lessons/Lessons_Soil/feelmethod.html

    which is much quicker (then again I map and classify soils daily for my job) and as equally accurate as any home jar method.

    Here is a link that might be useful: Here's a similar method with dispersal agent

  • Kimmsr
    14 years ago

    If the soil you have does not have any clay in it the jar test will not show any. If the soil you are testing does not have any sand in it the jar test will not show any. What the jar test is mostly for is to see how much organic matter is in your soil and help guide you in getting a good amount into that soil.
    Since I have never had to add anything except soil and water to the jar to get a good and accurate result, and since the professor of soil science I long ago got this simple test from stated that nothing exceopt the soil and water needed to be added to get a good result, I see no reason to add anything to flocculate or hold in suppension any part of the soil and that could skew your results if you did.

  • piedmontnc
    14 years ago

    Again, you don't know what you're talking about, it's as simple as that.

  • gargwarb
    14 years ago

    piedmontnc summed things up rather nicely but I'll just chime in with this:
    When testing something, isn't it counter-intuitive to introduce additional ingredients? :

    Actually, the majority of lab work is done by adding other ingredients. As we've been discussing, a deflocculating agent is added for the textural analysis. In regards to the chemistry portion, the lab has to knock stuff off of the surface of soil particles so that they can be measured by machines, which is done by adding a lot of different stuff, depending on your needs. Sometimes it's an acid, sometimes it's a chelating agent, sometimes is bicarbonate, sometimes it's a cocktail of reagents,etc.
    Many times, something is detected and measured through a titration in which you keep adding a chemical to a solution until you get the expected reaction and the amount of the chemical that you used tells you how much of the thing you are looking for is in the solution.
    Lab work is all about adding stuff to what you're testing.

    Arsenic - strikes me as ubiquitous from the get-go.
    Yes, it is.
    How much is too much?
    That's the sixty-four thousand dollar question and the answer depends on a number of factors. Are you concerned with human exposure to the soil? Plant toxicity? Toxicity to you due to uptake of arsenic by the plants? Ground water contamination? All of the above? Because they will all have different thresholds.
    Then the answers depend on a whole slew of things including, but not limited to, depth to the water table, soil texture, organic percent, soil pH, the form that the arsenic is in, what you're growing and on and on.

    Again, I don't think that every time someone uses ironite an angel cries or anything. I just think that there is an, as yet to be determined, potential for crossing one of those thresholds. When there are other options available, I tend to take the cautious route. That's just how I roll.

    kimmsr
    and since the professor of soil science I long ago got this simple test from stated that nothing exceopt the soil and water needed to be added to get a good result
    I've met some brilliant soil science professors, some that pretty much know what they're talking about and some that I have an urge to call after every good rain just to make sure they didn't drown while looking up to see what was falling on them. Don't be too star struck by the title "professor".

    I see no reason to add anything to flocculate or hold in suppension
    I know ya don't, buddy. I know ya don't.

  • Laurel Zito
    14 years ago

    But, I want people to know you can buy other brands of Iron and avoid Ironrite if you really think you need to add iron. I had bought some lily miller iron in a shaker can, but then I found out the yellowing of the camilla was due to a lack of nitrogen in the winter. I did not feed it in the winter and got yellow leaves, but on subsquent years I gave it low amount of nitrogen in plant foods and avoided the yellowing leaves. The only reason to add iron is you are trying to correct a problem called chlorosis in your plants.

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