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are the intestine
of the soil.
the future of food

Seer Centre report
rock powder
soil amendments
How to Improve Topsoil
Testing Aggregate Industry By-products
Review and comment
on USDA 3-year study of mineral fines

by David Yarrow, January 1998


In 1991, Dan Winter of Crystal Hill Farm in Eden, New York called Gernatt Gravel Co., New York's largest aggregate mining company, to order a load of mineral fines. David Hope, an Eastman Kodak biochemist, had analyzed samples of rockdust from western NY quarries and found Gernatt's Springville quarry had the best trace element analysis.

Bob Able, Gernatt's sales manager, was surprised by Dan's request, since to his industry, mineral fines are a by-product with few useful purposes. Aggregate producers crush and screen stone into three grades of gravel and two of sand. A very fine dust washes out in the screening water, which is pumped to a settling pond where it becomes "mud." Periodically the settling pond must be dredged to remove these clay-like sediments. Mostly, this fine dust is a nuisance—a waste—that must be tediously handled and carefully landfilled.

Bob asked why Dan wanted this waste. Dan explained it restores minerals lost from topsoil by constant use, fertilizers, acid rain, and leaching. A long talk revealed quarry dust can supply the trace elements needed by soil microbes to revive worn out soils. Plants grow stronger, taste better, need less fertilizer, resist pests and disease better, and store longer. At the time, Bob didn't know a microbe from a mushroom, but he knew minerals.

Bob was also New York State Director of the National Aggregate Association (NAA), the trade group for aggregate (sand and gravel) industry. NAA had just established a research foundation., and was looking for something to study that could benefit the industry.

An average gravel quarry produces 10 to 20% fines-up to 10 ton per day-half a dump truck. The entire aggregate industry generates over 200 million tons a year. At a generous 20 tons per acre, this is enough powdered rock to cover 10 million acres.

So, in spring 1992, with Bob's help, I wrote a 30-page proposal outlining an NAA investigation of using mineral fines as an amendments in agriculture, forestry and compost. In July 1992, our plan was endorsed by NAA's Research Committee.

(The next month, while visiting Wisconsin to research an article on the hazards of the electric power grid, my left hand touched a 6,000 volt power line. Unconscious, badly burned, I then fell 15 feet to the ground. The collision shattered my spine and ribs. While I recovered from this near-fatal catastrophe, the NAA-funded research effort rumbled along.)

The pace was slow while NAA finished setting up their new research foundation at Texas A&M University. National Stone Quarry Assoc. joined the research group. USDA and Bureau of Mines took interest in the research, and HUD's agency for community-scale composting , too.

In 1994, agreements were complete, and USDA's Agricultural Research Service (ARS) in Beltsville, Maryland began field trials of industry by-products. In May, ARS hosted a Remineralization conference, with talks by Remineralize the Earth editor Joanna Campe, New Alchemy's Greg Watson, North Carolina forestry expert Dr. Robert Bruck, and others. In 1995, Bob Able's own article describing the research purpose and plan was published in Pit and Quarry, the aggregate industry trade association magazine.

For three years, ARS grew a corn-wheat-soybean-wheat-corn rotation on small test plots. Each plot was treated with one of five types of mineral fines, fertilizer and "composted yard waste." USDA scientists took 42 soil samples, ran over 100 elemental analyses, and made a dozen other measures of each crop in each plot.

In March 1997, a report on this complex study was released.

Urban & Rural By-Product Utilization
1994-1996 Pilot Test Demonstration Plots

condensed from the ARS research report: February 15, 1997

This study was initiated as a demonstration trial to observe and quantify the effects of a number of industrial by-products in an agricultural situation. The trial was carried out for three years. These demonstration plots are part of a larger study on by-product utilization.

The 3-Year Demonstration Plots were designed to examine mineral 'fines,' cement washings and coal combustion bottom ash, compared either 'as is,' or combined [with] composted yard waste. [The] main purpose was to increase awareness of inorganic materials, and show that many can be used as soil amendments in agriculture.

All these demonstration plots are not replicated, therefore any conclusions drawn from the study should be considered tentative. [There are no] formal conclusions for there were no replications. Therefore, there [is] little validity in such comparisons and drawing conclusions from them

For many materials the limiting factors will be two-fold.

First, any material in agriculture must exhibit a 'beneficial use.' Many state departments of environment argue that if a 'beneficial use' cannot be established, then one is simply disposing of the material.

Second is economics. Many by-products have low value. Even loading the material onto a truck, no less transporting and applying the material, is not economically feasible.

For many by-products both limitations can be overcome by co-utilization: composting and/or blending to create a value-added material.

Any comments, suggestions or ideas for future interactions will be most welcomed.

Ron Korcak, 301-504-6591; 301-504-5521 fax

Test Materials
Glacial Gravel
Cement dust
Bottom Ash
Augusta, GA
Collins, NY
Medford, MD
Washington, DC
Chalk Point, MD
Mineral Fines: Construction aggregates are crushed, then screened to remove sand and gravel. About 15% of parent material remains as dust (200,000+ tons/year). Three types were studied:
  • Georgia Granite
  • New York Glacial Gravel
  • Maryland Meta-basalt
    Cement Residue: After a delivery, cement trucks are rinsed to remove residues. Sand and gravel are recovered, leaving high calcium material. Washington, DC metro area produces 10,000 tons annually.
    Bottom Ash: Coarse residue from furnaces burning coal for electric power generation. Source was PEPCO's Maryland facility

  • Test Crops
    3-year rotation
    (Zea mays, Pioneer 3394) planted May 13. Control got 150 lbs/acre 10-20-10 side dressed at planting. Weed control by mechanical cultivation. Harvest Oct. 5.
    Winter Wheat (Triticum aestivum; Pioneer 2552) planted Oct. 21 as winter cover; 2.25 bu./acre, with 20 lbs./acre ammonium nitrate.

    (Glycine max; cultivar Chesapeake) planted June 1. Starter fertilizer at planting (150 lbs./acre 10-20-10) Weed control by mechanical and hand cultivation. Harvest Oct. 30.
    Winter Wheat (Triticum aestivum; Pioneer 2552) no-till planted early Nov.; 2 bu./acre. Harvest late May

    (Zea mays, Pioneer 3394) planted May 5; 26,600 plants/acre. No fertilizer, by-products or compost. Pre-emergence herbicide applied; no other weed control.

    Test Plots
    Seven test plots
    7 x 24 meters.

    Five got a single test material at not more than 10 dry tons/acre. Half of each plot received LeafGro, a composted yard waste from Prince George County, Maryland recycling center at 67 tons/acre (28 dry tons).

    Two control plots got yard compost. Half of one control got fertilizer at each crop's recommended rate. The other control got no treatment at all.

    This meant 13 samples in each set of tests:

  • by-product (5)
  • by-product + compost (5)
  • compost only (1)
  • compost + fertilizer (1)
  • no treatment (1)

  • The Tests
    Early 1994: three random samples before application of materials
    Nov. 22, 1994: random cores from each plot.
    ??, 1995: ???
    October 1996: after final corn harvest.

    1994 Corn
    Tissues: Ear leaf samples, July 19; element analysis
    Yields: from four rows, bu./acre
    Grain: element analysis

    1994-5 Winter Wheat
    Biomass: May 10, 1995, 30 sq. ft. per plot
    Tissue: element analysis, stalk & head

    1995 Soybean
    Yield: Four 10-foot rows; wet & dry pod weights; dry bean weights
    Tissues: No foliar samples
    Grain: element analysis

    1995-6 Winter Wheat
    Biomass: 3 x 10 foot strips; fresh & dry weights
    Tissues: Composite element analysis.

    1996 Corn
    Yield: fresh weights & percent water
    Grain: element analysis

    Test Results
    On average: pH 6.4
    high Mg & P; low K; moderate Ca
    CEC 7.4 meq/100g
    2.7% organic matter
    trace elements Cu, Mn, Zn in normal ranges

    Soil Samples
    pH: cement dust increased most; compost lowered
    compost elevated extractable Mg, P, K, Ca, CEC, Cu, Mn, organic matter, soluble salts, B, SO4-S, Zn

    pH: all soils increased; no consistent effect from compost
    cement dust caused highest pH; bottom ash reduced pH
    compost elevated Mg, P, K, Ca, B, Mn, Zn, and organic matter more than any fines.
    little effect on Cu or soluble salts

    pH: all soils increased; no consistent effect from compost
    generally, compost elevated Mg, P, K & Ca.
    many minerals raised above pre-treatment levels

    1994 Corn
    Tissues: Ear Leaf elemental analysis
    N: all low
    P: all adequate
    K: generally all compost plots adequate, non-compost low
    Ca: .40%
    Mg: .20%
    Mn & Fe: elevated by compost
    Zn & Cu: little difference
    Boron: compost increased
    As: no differences;
    Cd, Cr, Al, Ni, Pb: little difference in fines, compost highest, higher in meta-basalt.

    All materials increased yields
    Highest for compost plus fertilizer
    Compost increased vs. fines alone

    Grain: elemental analysis
    N & P: little differences
    K: all compost higher
    Ca & Mg: depressed by compost
    Mn, Fe & Na: elevated by compost
    Cu & B: no difference
    Al, Zn & Cd: highest in compost, with & w/o fertilizer
    Cr & Ni: slightly high w/ metabasalt
    Pb: some differences

    1994-5 Winter Wheat

    compost + fertilizer produced most
    compost + any fines increased
    compost increased vs. fines alone
    compost + glacial fines produced most among fines

    Stalk: elemental analysis
    compost increased P, K, Cu, B, Al, Zn, Mo
    Cd & Co higher with compost only
    all other elements showed no trends

    Head: elemental analysis
    compost co-applied increased Cu, Zn, Na, and Mo; decreased Ca
    no differences in P, B, and Pb
    all other elements showed no trends

    1995 Soybean
    metabasalt granite w/ fines, glacial w/ or w/o compost, cement, ash increased vs. compost only or control
    Overall, compost effect inconsistent, dependent on by-product

    elemental analysis
    N tended lower w/ compost + fines.
    P & K tended higher with compost
    Fe higher with all fines vs. compost only, or fertilizer
    Al: no trends, bottom ash highest
    Mo & Co inconsistent
    Ni: metabasalt highest, grain lowest

    1995-6 Winter Wheat

    generally lower than 94-5, low seed germination
    fines+compost out-yielded fines only
    granite w or w/o fines yielded same

    1996 Corn

    inconsistent w/ fines + compost
    Compost + fertilizer out-yielded compost + fines
    Cd, Pb and Ni lower in grain

    The Data (available as 18 tables on 5-pages of Excel spreadsheets)

    my turn
    The Emperor's New Fertilizer
    Needed: a closer look, a broader view

    by David Yarrow

    This isn't just another experiment with "mineral fines," but the first USDA look at using rock powders as mineral amendments. This USDA study offered us perhaps the most intensive scrutiny yet of effects of rock powders on soil and crops grown in that soil. The complex sets of samples and extensive tests were expensive, precise, tedious, and require a professional skill and funding far beyond the simple pot tests Remineralize the Earth has urged for years. These kinds of comparisons of several materials could give us insights into the interactions in soil that transform mineral into vegetable.

    Test results themselves are positive and gratifying. While the sheer mass of data generated by such a complex study can obscure the obvious, a few simple truths come clear. Overall outcomes repeat what we've read and said for years. Specifically, general data trends reveals that:

  • Mineral fines only work almost as well as fertilizer
  • Mineral fines plus compost work better than fertilizer
  • Soybeans—a microbe-sensitive crop—responded best to mineral fines and compost.
  • No measurable increased uptake of biotoxic heavy metals

    Yet, after waiting over four years, the outcome of this USDA study is disappointing. What seems obvious is that USDA scientists don't yet understand mineral fines, trace elements, composts, or microbes as foundations for soil fertility. Since I wrote the original proposal that instigated this inquiry, it is my right and duty to scrutinize and judge the consummation of my initiative. And since the urgency that sparked this investigation is how to heal a badly damaged planet, what I look for isn't more favorable results, but shifts in thinking to a new awareness of the web of life, and changes in soil fertility strategy.

    Regrettably, the scientists keep their narrow-vision, double-blind "skepitcals" tightly on. So, while the researcher sees this as only one unreplicated experiment, it joins dozens of studies, reports and testimonials in our files, many tracing back over a hundred years. The consequence of this near-sighted mindset is a failure to rediscover basic principles shown and known in earlier decades and centuries.

    The research design itself shows narrow conception and shallow insight, and fails to focus on key links in soil nutrient cycles. The (lack of) response and recommendations indicates failure to grasp connections between mineral fines and human health, and the dimension of our endangered ecosystems. While every cautious investigator refuses to draw conclusions based on one experiment, I hoped for a more sensitive, sensible design, and a more thorough, thoughtful discussion of results.

    This is only a test....

    While there is much to criticize about this study, I certainly hope USDA and NAA will pursue further research into the use of mineral fines. Julius Henzel, John Hamaker, Walter Ruegg, George Earp-Thomas, and others in the past who investigated minerals and microbes in soil ecology all performed tedious, repetitive tests—not to prove a theory or fertilizer, but to understand how and why remineralization works. So, I urge any future USDA researchers to look more deeply into this subject. There is more here than chemicals and crops, and there is more at stake than disposing of industrial wastes.

    The experiment is mired in a "materials" mindset that fails to see the chain of life that weaves mineral into microbe, and then into plant. The focus is on the mineral fines, not the processes and players that participate in this transformation. These researchers seem to have no clue how particles of rock are transformed to wheat straw, corn stalk, or bean bush.

    Granted, the appointed task was to test by-products, not study and recommend remineralization strategy. Yet, a rule of both science and divination is that to get clear answers, you must ask clear questions. Ask ambiguous questions, and you get vague, opaque answers. Ask narrow questions; you get thin answers. Ask the wrong question, you get misleading answers. Don't ask a question, you get no answer.

    Comparing Bananas to Beef

    First, it is dubious design to compare mineral fines with chemical fertilizer. Comparing apples to oranges has more validity. These materials aren't equivalent as fertilizer, so comparison isn't appropriate or logical. While rock powders can reduce the need for chemical fertilizers, mineral fines can't substitute for the big three nutrients.

    These two types of soil amendments aren't at all interchangable, but complementary. They provide different nutrients (1, 2, 3 below) by different strategies (4 & 5).

  • Conventional fertilizers supply major minerals (N-P-K)
  • Cement dust (limestone) supplies Ca and Mg.
  • Rock powders supply minor and trace elements (Fe, Cu, Zn, B, Se, Co, Mo), plus more whose role in soil, microbes and plants is poorly understood, if at all.
  • Conventional fertilizers rely on solubility to supply nutrients to plants via the "soil solution.".
  • Rock powders require soil microflora to digest minerals into protoplasm, and then feed them to plants.

    A more valid approach would be to test mineral fines with and without fertilizers. More appropriate would be to compare chemical fertilizers against compost, with and without fines.

    Second, spraying soil with herbicide is contrary to understandings of how rock powders become plant foods. Creating fertility isn't a mere matter of pumping chemicals into plant roots, but nursing and culturing a stable living community of interacting soil organisms. Herbicides subject soil organisms to harsh, toxic chemicals that can seriously disturb and weaken this fragile community. Many herbicides are broadly biotoxic, outright kill microbes, thereby interrupting the digestion of minerals into protoplasm..

    Compost is not Waste

    The issue of compost highlights the confused, incomplete thinking underlying this study most of all. Repeated reference to compost as "yard waste" is an obvious symptom of a blind mindset—a choice of words that undercuts its true value, and underplays its role in soil fertility. This "soil conditioner" doesn't even rate an elemental analysis alongside mineral fines.

    Compost isn't waste, but a seriously deficient—often desperately needed—soil resource. One clear study result is that compost plus any other amendment increases yields and minerals. Yet, these scientists seem to see compost as little more than a sterile potting medium, like peat moss or perlite. The notion compost is a nutrient isn't considered at all; its role as microbial inoculant isn't stated, or designed into the study.

    Nor is there recognition of compost quality, yet the potency of composts varies greatly. The raw materials incorporated in a compost heap significantly affect the fertility and vitality of the finished fertilizers. For example, biodynamic composts are carefully made by precise methods with special ingredients, and "potentized" by inoculants to rapidly infest a fermenting pile or field with mineral-hungry microbes and digestive bacteria. Compost from "yard waste" probably has little of this extra kick.

    The idea that compost might be made with mineral fines in the mix isn't mentioned or tested. Yet, a compost pile's plentiful populations of microbes are an ideal environment to digest raw rock minerals and mobilize them to root hairs. While the suggestion of "co-utilization" could include mixing mineral fines in compost blends, the report fails to identify this possibility or discuss it.

    Whither the Microbes?

    The agriculture scientists still treat mineral fines as a plant nutrient, ignoring the complex interactions that occur in healthy, living soil. In the entire study, there isn't one reference to soil "bacteria," "microbe" or "fungi." They make no effort to detect soil microbes, or measure this soil biomass.

    Yet, it is micro-organisms that really benefit from rockdust. It remains our belief that it is microbes that consume primary rock minerals and package them for feeding to plant root hairs. For two decades we insisted "feed the microbes"—they feed the plants, and everything else that lives in, on and from soil.

    Granite and basalt are igneous rock, with dense, crystalline molecular structure. To transform these hard, insoluble stones into nutrients fit to feed plants requires the digestive abilities of microbes. Conventional fertilizers bypass this biological feeding chain to inject soluble salts right at roots. Feeding salt fertilizer to plants short circuits the natural, biological processes—like raising a kid on candy, cake and ice cream.

    It is ironic that while Biotechnology engineers microbes to eat oil spills, manufacture drugs and engender herbicide resistance, little recognition is bestowed on ordinary microbes that digest rock to make minerals available to plants and synthesize special biomolecules, including enzymes, vitamins and hormones. More tragic is the fear that enables companies to sell household products as "anti-bacterial" while pushing food irradiation to reduce risks of bacteria contaminating food.

    Meanwhile, agricultural science continues to ignore the role of microbes in soil and plant nutrition. So, even as "a prophet is without honor in his homeland," it seems bacteria are invisible and ignored in their one true arena: the foundation of the food chain—where geology meets biology.

    Dust is Dust, but Ashes are Ashes

    Including cement dust and bottom ash is regrettable. Neither is a natural rock powder, but are significantly changed by artificial processes. Glacial gravel, metabasalt and granite are natural stone, but cement and ash are changed by heat, which alters their chemical state and biological effects. While is isn't wrong to compare them all together, the choice blurs important qualitative distinctions that can confuse public perceptions.

    Notably, elemental analysis for bottom ash is missing from test data. Of all the by-products, incinerator ash is most likely to contain toxic contaminants, and the most variability in chemical composition. So omission of this data is a glaring deficiency.

    Today there is growing concern about farmland being poisoned by dumping hazardous wastes from industry and mining into fertilizer mixes. To include ash and cement in this study creates a dangerous potential for confusion. And to leave the ash analysis out compounds this risk of confusion. There's no comment on these issues—another serious oversight.

    Facing the Dragon

    In his extremely sparse comments on the study, Ron Korcak identified to main obstacles to wide use of mineral fines as fertilizer. The first is political: threading the needle of state fertilizer regulations. The other is economic: whether it is cost effective to transport and spread these minerals. While both issues are genuine and pragmatic, such a narrow analysis is a great disappointment. Such values may satisfy the concerns of industries seeking markets for their by-products, they are insufficient to the concerns that first stimulated this research.

    The first purpose of remineralization is to revive worn-out, depleted soils, not to replace or be interchanged with chemical fertilizers. Nor to boost productivity and profits. Pampered soils at USDA's Beltsville Research Center don't compare to thin over-extended and sterile soils of farmers struggling to maintain profitability in an unfriendly marketplace.

    The truth is that, while this strategy of mineral fines-into-fertilizer may not turn waste in wealth for industry, the real issues are health and survival—human, ecosystem and planet. We need new fertilizers much less than we need a new value system, priorities and sustainable technologies. "Sustainable" is another watchword that fails to appear in the text.

    The depletion of farmland by abusive, extractive farming practices in recent decades—including soluble salts and toxic chemicals—is one of the sleeping issues of our age. The exhaustion of soil by excessive use, deforestation and air pollution are global urgencies. Right up there with global warming and nationalistic war. This USDA study gives not the least hint of recognition of this context.

    What's also missing are visual images and personal impressions—subjective observations of experimenters. I mean, no one reports how the corn, wheat and soybeans taste. Data alone can be incomplete, even deceptive. Most of all, we know remineralization works—not because we read nice numbers in research data, but because we saw how rock powders affect soil, plants, earthworms, compost, and entire eco-community. The very idea of putting little bits of this and that on tiny postage stamps of soil denies the truth that "everything is connected."

    If we don't see the problem, we'll never find the solution. Even if it's right in front of us. To have our brave new world, we must be brave and big-hearted enough to face our dilemma's true dimensions. Government regulation and cash flow are speed bumps in the road to sustainable agriculture and society.

    So hope of favorable results is reduced to another round of spiritless, mechanical treatments. And soil remains a dumping ground for industrial chemicals, not a living matrix that must be built, nursed and sustained. Especially maddening, because our urgent need to remineralize is precipitated to significant degree by the chemical mentality that designed this study.

    I certainly urge USDA scientists and industry to pursue further inquiry into the use of rock powders to restore worn-out soils, and to improve the quality of crops. But I equally hope the next field trials will be designed to really see and study what happens to transform mineral into microbe into plant.

  • see also
    Soil Remineralization
    future market
    for aggregate industry fines
    Robert J. Able
    Pit and Quarry, June 1995
    see also
    Soil Remineralization
    aggregate into agriculture
    Mark Kuhar
    Pit and Quarry, January 1998
    Missing Element
    in the Climate Change Equation
    September 2005

    how a single trace element in topsoil essential to a single enzyme in one bacteria can exponentially accelerate removal of carbon from atmosphere, and thus slow global warming and climate change

    Recycle the Sea

    "My research clearly indicates Americans lack complete physiological chemistry because the balanced, essential elements of soil have eroded to the sea. Consequently, crops are nutritionally poor, and animals eating these plants are, therefore, nutritionally poor.

    From the start, my sea solids experiments produced excellent results, and it conclusively proved that the proportions of trace minerals and elements present in sea water are optimum for growth and health of both land and sea life.

    "We must alter the way we grow our food, the way we protect our plants from pests and disease, and the way we process our food."

    Dr. Maynard Murray
    Medical Research Doctor
    Sea Energy Agriculture

    The Earth Renewal and Restoration Alliance — www.ancientforests.uswww.carbon-negative.uswww.nutrient-dense.info2/14/2009