Forest Soil Improvement
a simple experiment
David Yarrow, January 2002

BACKGROUND
Today's soils—both forest and farmland—are weak, damaged depleted. Over-intensive use, clear cutting, farming with plows, and accelerated aging from air pollution, especially acid rains, have exhausted the fertility of our topsoils. Early settlement land clearing and plowing caused humus-rich virgin forest topsoils to rapidly erode and oxidize. Most forests in today’s New York were once cleared farmlands. The industrial era brought precipitation with declining pH, and acid rain and snow increase the rate metallic elements leach from soil.

In a soil system, heavy elements—the trace elements—dissolve most rapidly, leaving the lighter, major minerals. In biological systems (plants and animals), the trace elements have far greater effect—out of proportion to their quantity—because they are chemical keys to create regulatory molecules such as enzymes, hormones, vitamins, and specialized proteins.

Ecosystem restoration and forest regeneration must begin with serious efforts to renew topsoils by restoring minerals, especially alkaline minerals and trace elements. Soil improvement must address three primary factors:

1. minerals (elements)
2. organic matter (carbon, oxygen, nitrogen)
3. microbial activity (micro-organisms and insects)

This experiment focuses on the first and most fundamental of these three—soil minerals—with a particular focus on micro-nutrients—the trace elements. The assumption is made that the forest soils in this test already have adequate supplies of organic matter and microbial activity, but are running out of primary minerals.

GENERAL PLAN
The plan is to compare the effects on forest flora of four different rock powders, each applied at three different rates.

This experiment will supply minerals to soil in the form of natural rocks, finely ground to powder consistency. Rocks are the original source of soil minerals. Minerals in rocks are essentially insoluble (less than 1%), and only made available to plant roots through digestion by bacteria and other micro-organisms. When ground to small particles, the surface area of a rock increases exponentially, thus the rock is exposed to more rapid digestion by bacteria, quickly assimilated into soil, and its minerals are made available to plant roots.

PLAN DETAILS

1. Test Site: The experiment will be conducted in the old growth area, because this allows observation of effects on an entire forest ecosystem, including large trees, small trees, seedlings, shrubs, and ground-level plants. The goal is to assess soil improvement in forest regeneration strategy, not just stimulate growth in trees.

   Testing on trees is more difficult than annual crops because tree roots spread out much more, requiring larger test plots, and making complete plot isolation impossible to achieve. Also, trees permit more limited methods to measure biomass and mineral uptake.

2. Test Plots: Minimum plot size is 50 feet square; 100 feet would be better, but requires more space and labor than is easily available. For demonstration purposes, 50x50 will be sufficient.

   Easiest plot layout is a square grid, shown at right, above. With 50 foot plots, the entire experimental site is a 100x100 foot square. This is divided in four quadrants—one for each test material. Each quadrant is further divided in four 25x25 foot sections.

   Four middle sections are untreated (0x) to form a large control area at the center of the site. The outer three sections in each quadrant are treated at different doses (1x, 2x, 3x). This allows easy visual inspection of the test area.

   If a contiguous square 100x100 feet cannot be designated, a 50x200 foot test plot can be laid out.

   

   Alternately, the test plot can be circular (shown at right, lower). Again, inner four sections are untreated controls, while four materials at three doses are applied to outer sections. All sections have the same area. This circular plot layout is even easier to visually inspect, but hard to layout amid trees and shrubs.

   Careful intelligence must guide selecting the old growth area, to assure the site chosen can elicit significant responses that can be both measured and compared.

3. Test Materials: Four different rock powders will be spread on four test plots. Materials are selected for their capacity to supply trace elements. From my experiences with agriculture, I recommend three with good confidence:
   • Planters 2: a “gypsiferous shale” from a fossil mineral spring deposit in Salida, Colorado. Marketed for 60 years for agricultural use as "trace element fertilizer” and feed supplement. (cost: maybe $25 per 50 lb. bag; 3 bags required)
     See: How to Make Topsoil
   • Azomite: a “montmorillonite clay” from central Utah. An ancient sea floor sediment (geological compost) from areas adjacent to the Great Salt Desert. Marketed for 75 years as a colloidal trace element soil amendment. (cost: maybe $35 per 40 lb. bag; 3 bags required)
     See: Trace Elements, Trees and Tomatoes
   • Glacial Gravel Dust: a locally abundant by-product from sand & gravel mining of glacial till. The Valente quarry on Route 66 in Wyantskill has suitable material, at a cost of maybe $10 per ton*. Most of the cost is for transport. The proposed experiment won’t require a full ton of glacial gravel dust. I suggest acquiring a truckload, usewhat is needed for the forest soil experiment, and incorporate the remainder into gardens, where it is sure to have beneficial effects.
     See: Stone Age Agriculture
   • fourth material, not yet chosen: several other materials are available to test, including granite dust, Summa minerals, Strite’s dust, sea solids, Volcanite, Blacksand, or Greenrock. My advice is to select a local or regional material with high paramagnetism, or dense crystalline structure, or both.
4. Soil Tests: Before any materials are applied, representative samples of topsoil from six inches deep in each of the four quadrants will be collected. Three tests will be done of each sample:
   • Simple home lab tests by Niskayuna High School students to measure pH, Nitrogen, Phosphorus, Potassium
   • County Cooperative Extension tests for pH and major minerals ($5 per test; 4 samples = $20).
   • Cornell University tests for major minerals and trace elements ($12 per test; 4 samples = $48 + shipping)

   Additional soil tests can be taken at six month intervals if this data seems useful. Generally, tests of soil chemistry and their interpretation provide limited insights into soil fertility, versus observations of plant behavior, but these analytic methods can identify deficiencies and confirm significant changes in some elements.

5. Application Rates: Each 50x50 test plot is subdivided into four 25x25 subplots. One fourth of each plot—the central section—will be left untreated as a control. The other three one-fourth sections will receive amendments applied at three different rates: 1x , 2x and 3x (or: half bag, full bag, 1½ bags = 3 bags per test plot). In agriculture, application rates for Planters 2 and Azomite are at least 250 lbs. per acre. In a forest, a lighter application will be adequate.

   Care must be taken to assure a uniform distribution of the materials over each the 12 test plots. Materials must be spread by hand, so a suitable procedure to apply them evenly and precisely must be devised. Because these materials are so fine, they must be spread carefully on a windless day to assure each material settles only on its targeted section.

   If a fourth bag of each material can be purchased, application rates can be set at: 1x ( ½ bag), 2x (one bag), 5x (2 ½ bags). This combination of light, moderate and very heavy applications may highlight dosage differences and yield better insights. The goal of this soil improvement process is to restore soil minerals to pre-colonial levels. This may be accomplished in one application in a single year (5x), or a series of smaller applications over a few years (1x).

6. Baseline Data: Before applying any amendments to test plots, specimen trees and other notable plants in each quadrant will be marked, counted and measured. Best done in early October, before leaf drop makes identification difficult and uncertain. Ideally, if test plots are setup, baseline data is recorded, and amendments spread in late autumn ({October), minerals will be digested through the winter and ready for the spring growing season.

   Specific numerical data will be collected on these features of each section:

   • Tree Inventory: A detailed inventory of all trees in each 25x25 test section will be taken. Significant specimen trees in each of four classes that can be easily measured will be marked and mapped. Trees will be classed as:
     1. large (over 6 inch dbh)
     2. medium (over 12 feet tall, up to 6 inch dbh)
     3. small (5 to 12 feet tall), sapling (under 5 feet tall)
     4. seedling (new year’s growth)
   • Seedling Trees: To monitor any increase in seed germination and seedling growth, the number of seedling trees and species in each test section will be noted.
   • Girth: Most easily, girth (caliper) of significant specimen trees in each class will be marked, mapped and measured.
   • Height: A few significant specimen trees in each section will be selected, marked and measured for height. A few will be large trees, but small and sapling trees are easier to measure, and more likely to clearly show significant effects.
   • Understory Vegetation: Understory plants (shrubs and herbs) will show response, too—perhaps quicker and more dramatic than trees. Many herbaceous plants are ephemeral—they appear and disappear seasonally, making them hard to count. The number of plants of significant species in each section will be counted and recorded.
   • Observations & Anecdotes: In addition, subjective observations and anecdotal perspectives will be logged in experimental records. These observations can contribute insights to design further experiments in soil improvement. In particular, information about tree resilience and resistance to stress, pests, disease, drought, and frost will be valuable.

7. Semi-annual Assessments: Measurements of trees and understory plants will be taken twice a year (June and October) for three years to monitor and measure any response to the amendments. Specific numerical data will be collected:
   • Seedling Trees: Seedling trees and species in each test section will be counted.
   • Girth: Marked specimen trees in each class will be measured.
   • Height: Marked specimen trees in each section will be measured.
   • Understory: Understory plant populations (shrubs and herbs) of significant species in each section will be counted.

In an agriculture experiment, we would measure total biomass by harvesting and weighing the crops. But this is impossible in a complex forest environment with perennial species.

DATA TABULATION
Numerical data will be tabulated and analyzed to identify significant differences in growth rates and populations. Expectation is to see small differences in data collected in June 2003 near the end of the peak spring growing season. Differences in growth rates should become strongly obvious in data collected at the end of the first growing season in October 2003. Measurements each spring and fall thereafter should increase these numerical differences.

Additional soil tests can be taken at annual intervals to identify significant changes in some elements.

EXPECTATIONS
At the outset, two obvious effects are anticipated:

1. increased growth rates, meaning treated trees show greater gains in height and caliper
2. increased fertility, meaning treated areas show greater numbers of seedling trees and understory plants.

UNMEASURABLE EFFECTS
My experience with rock powders showed dramatic boosts to reproductive and immune system functions. Plants flower more profusely, and set seed more copiously. Those seeds are more viable, and fall on soil that is more fertile, which results in greater success self-sowing, and successive outbursts of seedling populations. So measurements of any effects on seed fertility, germination and survival are especially important.

Generally, an increase in vigor and vitality indicates an improvement in immune system activity, which confers improved resilience to endure stress, and to resist insects, fungus and diseases. With biological populations in ecological communities, even a small percentage shift in seedling survival can tip the odds away from extinction and toward abundance. These soil amendments will probably reduce disease and insect damage, but such effects are hard to document, measure and evaluate. Such effects require a more controlled scientific experiment than this simple demonstration test.

INTANGIBLE EFFECTS
Perhaps the most important measure of soil improvement is an increase in biological activity—an explosion of microbial organisms digesting the rock dust. However, there are no effective technical methods to measure this feature of soils beyond a rudimentary test for respiration (oxygen consumption), or very tedious population counts under a microscope.

BACKGROUND READINGS
For background on soil improvement with rock powders, and on some of the materials used in this work, see articles in the Topsoil section of the TERRA website. In particular, the following articles may be most relevant:
Fire in the Water: how geology becomes biology www.championtrees.org/topsoil/firewater.htm
Sea Energy in Agriculture: www.championtrees.org/topsoil/SeaEnergy.htm
Renewing Australia's Ancient Soils: www.championtrees.org/topsoil/australia.htm
Regenerating Appalacian Forests: www.championtrees.org/topsoil/bruck.htm
Climate Change and Topsoil: www.championtrees.org/topsoil/feedsoil.htm
A Secret of the Soil: www.championtrees.org/topsoil/EarthPlus.htm