When soil tests are done, one recommendation will be adding limestone (calcium) based on pH. (I think every soil tests I have seen recommended two tons to the acre, so it may be programmed into the system.)

In his book "More Food From Soil Science: The Natural Chemistry of Lime in Agriculture" Dr. V. A. Tiedjens makes a rather compelling case pH, by itself, is not a good indicator of the need for soil for calcium. For example, in some trials he applied what would be a hugh amount of limestone to an acre and pH actually went down. He maintained in a standard soil test results the need for limestone is understated by half or more.

He considered calcium to be just as important fertilizer as NPK.

Basically he said a far better indicator than pH was the base saturation of calcium, which should be at least 85%. Once that level is reached, good things start to happen.

This was his calculation, as a starting point, for the amount of available calcium needed per acre foot in pounds per acre: Sand - 400-800, loamy sand - 800-1,600, sandy loam - 1,600-2,400, silt loam - 2,400 - 3,600, clays - 3,600 - 4,800, clay loam 4,800 - 6,000 and muck soils - 6,000 - 10,000. For soils with low organic matter levels, use low end of range. For soils with high organic matter levels, use high end of range. The finer the grind the more quickly it will become available to plants.

Note these recommendations were for available calcium, not pounds of limestone. A ton of high calcium limestone adds 600-800 pounds of calcium to the soil in the carbonate form.

Locally limestone is around $20 ton delivered and spread and local trucks hold about 16 tons.

Say your garden is 1/4 acre and you want to put on 4,000 pounds of available calcium before spring tilling. Use 700 pounds of available calcium per ton. For an acre that would be about six tons of limestone. Dividing this by four (1/4 acre) you would need to apply a bit over one ton of limestone on the garden. What you could do is to order a truck load, have most of it spread on a field, then (when the truck is lighter) have the amount desired spread over the garden. You can largely offset the cost by not applying NPK that year since high levels of calcium will help make what is already in the soil more available.

The next time you have a soil test done also ask for base saturations of various trace minerals. If your base saturation of calcium is lower than 85%, considering adding limestone, as required.

Dr. Tiedjens is one of the founders of Growers Fertilizer Solutions, which produces water soluble fertilizers for spraying on plants (foliar feeding). It is considered to be far more effective than application in grandular form. (And calcium can also be foliar fed by disolving calcium nitrate in water.)

Dr. Tiedjens book is still available from Growers Fertilizer Solutions, 321 Huron Street, Milan, OH 44846 (419-499-2508 - area code has probably changed). Last time I ordered the book cost $18. I have extra copies on hand and will send a copy for $20 postpaid (my cost) while supply lasts. (Ken Scharabok, 1645 West Blue Creek Road, Waverly, TN 37185.)

If you are willing to think outside the box on fertilization, I highly recommend Dr. Tiedjens' book.

-- Ken S. in WC TN (scharabo@aol.com), September 12, 2000

Answers

In the above post I should have noted there are two types of limestone, calcitic and dolomitic. Do not use dolomitc unless your soil is deficient in magnesium as it can run up to 35% in the limestone. Excess magnesium can cause more problems than increased calcium will solve.

Some advantages of liming with calcitic lime (from Growers): 1) it makes the soil looser, and thus easier to work, 2) it mellows soil to a much greater depth, 3) it improves drainage, 4) it speeds up oxidation, 5) soils will dry much quicker in the spring, 6) it can reduce the need for weeding, 6) dry weather will not be as much of a problem as excess water will be stored in the sub-soil to provide moisture when needed, 7) it helps prevent erosion by the soil holding more moisture, 9) increases quality of plants by increasing protein and miners, 10) reduces the need for nitrogen and potassium, 11) helps prevent winter kill of alfalfa, 12) tremendous boost to microorganisms and worms in the soil, 13) crops mature earier and dry down quicker, 14) hay dries much faster, 15) improves palatability of forages, 16) helps produce healthy plants which insects and pests will not eat and 17) increases the germination of seeds by up to 30%.

I have seen #16 mentioned numerous times in testimonials on the benefits of maintaining the proper level of calcium in soils. Basic comment was their neighbor's crops were being eaten up while theirs were being left alone.

If limestone is spread on fields and not tilled in, it will progress downward at the rate of about two inches per year, depending on how dense the soil is.

-- Ken S. in WC TN (scharabo@aol.com), September 12, 2000.

Another P.S. Put a layer of limestone between layers in your compost bin. It will not only improve the compost, but will also help to keep down odors.

-- Ken S. WC TN (scharabo@aol.com), September 13, 2000.

Thank you for the great article. I think many of us small farmers neglect the need for calcium in our soil, not only for our plant health, but also the health of our grazing animals, especially those who produce milk and eggs.

In my neck of the woods, the most valuble farming wisdom is, "You can never add too much lime." While I cannot get a truck to bring it in, I do buy it by the Subaru load.

-- Laura (gsend@hotmail.com), September 15, 2000.

While you probably cannot overlime, after you achieve and maintain 85% base saturation, any extra application will probably not be cost effective.

-- Ken S. in WC TN (scharabo@aol.com), September 15, 2000.

I have a question on this, Ken. If you are trying to improve soil, is there any information as to whether adding calcium itself or doing a couple of successive cover crops and tilling it in is better? On a large scale I am positive it is much more cost effective to add the lime, but on a smaller scale, I am curious as to level of benefits.

Thanks for taking the time to post this info, your ag expertise is appreciated!

-- Doreen (liberty546@hotmail.com), September 17, 2000.

When you till in cover crops basically what you are providing is organic matter in a readily available form. While it might provide some elements (in particular nitrogen) and trace minerals, they won't be much. IMO you would be much better off to apply an ample layer of limestone, and compost bid contents, before the cover crop is tilled in.

-- Ken S. in WC TN (scharabo@aol.com), September 17, 2000.