Soil test results...Lime recommendation doesn't seem right

Discussion in 'Pesticide & Herbicide Application' started by ThreeWide, Oct 7, 2004.

  1. ThreeWide

    ThreeWide LawnSite Bronze Member
    Messages: 1,116

    Recently did a soil test for a client. pH was 5.4

    In north GA, we have clay soils. However the recommendation was to add 25 lbs of lime per thousand. All of my other reference material says for clay soils it should be 75 lbs per thousand to raise pH by a whole point.

    This lawn was topdressed last year with mostly sand. Is that throwing off the soil test recommendation? Not sure which way to go here, because underneath the sand its all clay.
  2. Rtom45

    Rtom45 LawnSite Senior Member
    Messages: 456

    I can't answer your question about the PH, but I will suggest that you don't topdress clay soil with sand. Tests at Penn State show that any combination of sand/clay less than 80% sand is actually worse than either "pure" sand or "pure" clay. The current recommendation is to topdress clay soils with organic soils (compost,...).
  3. Luscious Lawns

    Luscious Lawns LawnSite Member
    Messages: 133

    I've never gotten a soil test back listing more than 25 per 1k. I think GDA suggests no more than 25# per1k per app to prevent the top layer of soil having too high ph. We never add more than 25 per 1k without winter being between apps. The freazing and thawing tends to incorperate the lime into the soil. If it is still low, in the spring we make 1 more app.

    ThreeWide likes this.
  4. turfsolutions

    turfsolutions LawnSite Senior Member
    Messages: 853

    Put 50 lbs per thousand now, and 25lbs per thousand in the spring. We use only pulverized lime. Comes out a powder, fast, very dusty, but good stuff. Wear a dust mask at least. Make sure you are using the correct type of limestone (calcium based or Mag. based.)
  5. hymark

    hymark LawnSite Member
    Messages: 1

    And for all growing crops, of course. My business specializes in soil fertility and what works for corn and wheat and other grasses works well in turf.

    I would apply 100 pounds of high calcium lime per thousand and 1200 pounds of gypsum or gypsum pellets per acre and whatever that is per thousand. This will balance the soil pH, make the fertilizer and herbicides work more efficiently and greatly increase air and water infiltration.

    If you need, help, don't be afraid to email me.
  6. heritage

    heritage LawnSite Bronze Member
    Messages: 1,351

    Turf unlimited,
    Take another soil sample and take plugs to a 6" depth. 1st test sounds very much off.

    Pete D.
  7. muddstopper

    muddstopper LawnSite Silver Member
    Messages: 2,341

    First off, your soil test recommendation is meant to incorporate the lime into the soil to a depth of 6 inches. When topdressing you are not incorporating anything, you are simply applying it to the top layer of the soil. Lime does not readly translocate into the soil. The amount of time it takes the lime to translocate is dependant on the partical size of the lime. The smaller the particals the faster it will work its way down into the soil. Lime has the capacity to neutralize approx a 1/4in radius of acidic soil in relationship to each partical of lime. A two inch thick layer of lime will still only neutralize 1/4in below its surface. The rest will just lay ontop of the soil until it eventually works its way down below the soil surface. Using smaller particals of lime will speed up this neutralization as long as proper moisture is available to help the lime translocate into the soil. For this reason it is best to apply lime in low rates several times instead of one heavy rate at one application.
    Your soil test results could have been altered because of prior applications of lime in the past. Your goals should be to provide proper ph in the layer of soil that the roots of the plant are living in. That might be six inches or it may only be two inches. For every inch of reduced root zone, (below 6 inches), or soil incorporation, you need to reduce your soil test recommendations by approx 15%. For surface applications of lime, such as topdressing, rates can be reduced by as much as 70%. With the remaining recommendation amounts applied in seperate applications. While it is not as critical on older established lawns because of the deeper root zone, on new lawns or new seedings, (overseeding) over applications of lime can slow and reduce seed germination and plant establishment.
  8. turfsolutions

    turfsolutions LawnSite Senior Member
    Messages: 853

    So if I have a soil test read 5.0 ph, then applying pulverized lime at a rate of 50lbs per 1000 square feet will slow seed germination and plant growth?? I disagree. I've been applying lime at those rates for 10 years on highly acidic lawns with very good results. If you apply 10 pounds or less per thousand, expect to take 10 years to adjust the ph to an optimum level. If you want the lime to reach deeper levels of the soil, then aerate prior to applying.

    my 2 cents
  9. muddstopper

    muddstopper LawnSite Silver Member
    Messages: 2,341

    Areateing is helping to incorporate the lime into the soil. My suggestions are simply meant for topdressing with lime when no soil disturbance is done. Lime rates should be adjusted for depth of incorporation. While heavy rates of lime wont necessary stop seed germination for new seeding or hinder already establish plant growth, it also doesnt promote fast germination or growth. Considering that the lime will only neutralize a 1/4in radius around the lime particals and the amount of time it takes for the lime to translocate into the soil. You could in effect raise the soil ph from 5.0 to 8.0 at the level that the actual seed is located and the actuall surface of the soil. Will this stop seed germination, no, but it isnt the 6.0 to 7.0 that we are looking for either. While not as critical on older established lawns, that is simply because the root zone is below the surface that the lime is applied to. Time and translocation will determine when the lime actually balances the soil ph at the root zone. Moisture levels determine how fast the lime will translocate as well as the lime partical size. Areation helps open up the soil making it easier for the lime to translocate to the root zone. My own experiences with new seeding, and I live next to the Ga state line altho I dont know how far from the orginal poster, is that lime rates over 35lbs per 1000 will actually slow seed germination and establishment. I have better success with rates as low as 10lbs per 1000. This is in spite of the fact that I have never had a soil test report indicate that I need less than 50lbs per 1000. Most places test recommendations call for 100lbs or more per 1000. This is when I am simply seeding on top of the surface and appling lime and fertilizer to the top of the soil. Whenever I am incorporating the materials I will adjust my rate to the depth of incorporation. You are correct that it can take years to adjust the ph of the soil to depths of 6 in or more when applying lime to the surface, but then again, do you really need to adjust the ph of the soil outside of the root zone.
    I suppect that the soil test that was taken by the original poster is probably acurate, altho a lot of varible exsist. The soil had a top dressing of sand applied last year. The lime will translocate thru the sand faster than it would thru the clay soil. Probably resulting in a stratisfication between the sand and the clay. Lime was probably added at the same time as the sand. The residual lime is probably what is makeing this test vary so much from previous samples. We also have no way of knowing if the person taking the sample used a clean core tool or to what depth the sample was taken. To simply suggest that he apply x amount of materials without taking some of these varibles into account doesnt lead to good advice, same for telling someone to use Calcitic based lime verses Dolomitic lime. We havent seen the soil test results so such suggestion are inappropriate. In the North Georgia area this person is more likely to need dolomitic lime because of the Magnessium deficiency in this area. But I wouldnt want to suggest that he use those materials without seeing the soil test results. Taking another sample to varify results is a good ideal but, if one is wanting to go ahead and do the work while he is waiting on the test results, using the minumim amount of lime would seem to make more sense. You can always come back and apply more lime but the stuff is pretty hard to remove. You could end up having to adjust the soil ph in the opposite direction.

    I am not doubting your success or even suggesting that your methods are incorrect. I am simply trying to help someone that had a question about his soil test results.

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