Catalytic "Genesis Effect" of Our Soil Building:
As this above Paper states, the approach that we are using is not new -- "Plantations are the oldest technology for the restoration of lands damaged by human activity".
The Need for Soil Building in CSA Reclamation:
The unquestionable consensus of scientific opinion is that post mining clay settling areas [CSA] have "damaged" soil characteristics:Highly Compacted Soils (Bulk Density).
Elevated pH levels (~8).
Very little soils organics.
Extreme deficiencies in nitrogen available to plants.
Extreme seasonal variations in moisture (e.g., modeling clay     in wet seasons to brick hard in dry seasons).
As we have repeatedly stated, "damaged" does not mean "worthless" as many anti-mining Interests incorrectly claim. CSA soils are very high in potassium (K) and phosphorus (P) -- two key components of productive soils.
Comparison Between Florida Sand
Soil and Phosphatic Clay (ppm):
However, we also disagree with overly simplistic & often misleading statements made by Industry Interests that "phosphate mining is a temporary land use" .
Clay ponds occupy about 40% of land mined for phosphate. Clay is washed from the phosphate matrix and a slurry of 3-5% solids is pumped to the ponds where the clay is allowed to settle.
Prior to development as a tree farm, our 60 year old CSA site was a prairie of cogongrass (which is very typical, especially for pre-1975 sites). While we would generally agree with Mining Interests that a label of "temporary land use" may be appropriate for overburden areas -- CSAs are a very different story.
Our CSA Site prior to tree planting with ~6 foot tall cogongrass
(tree line in distance is where the CSA ends -- the old dam).
We use the label "damaged" for only one reason -- to be absolutely clear that soil problems with CSAs do exist. By addressing the following soil remediation issues, we believe that CSAs can be highly productive for various land use.
|"[plantations] increase soil organic matter, lower soil bulk density, moderate soil pH and bring mineral nutrients to the surface and accumulate them in available form."|
The Plantation Approach:
In historical phosphate mining reclamation, approximately 50 native (e.g., cypress, pine, red maple, etc.) trees are planted per acre. In our plantation approach, tree planting density is between 2,000 (e.g., for timber, landscape mulch markets) and 4,000 (e.g., energy crops) trees per acres.
Under this reclamation approach, a key objective/focus is rebuilding/repairing soils where tremendous volumes of organic matter are introduced into the heavy compacted clay soils through the trees' root system -- resulting in a domino effect, catalytic impact.
|"In [a Plantation approach to] restoration, emphasis is given first to build soil organic matter . . . Once the soil characteristics have been restored, it is not difficult to restore a full suit of plant species". |
Sometimes a picture is worth a thousand words. Visualize that approximately 60% of the organic matter that you can see above ground (e.g., tree trunks, branches, etc.) has also been introduced below ground through the trees' root systems.
Same area as the above picture (that was cogongrass) after 3 years of tree growth. Final picture below is of current understory plants.
According to University of Florida (UF) Research on tree yields at our plantation, ~10 tons of organic matter is being introduced into the soils per acre per year .
|"[Plantations] can reverse [the mining] degradation process by stabilizing soils through development of extensive root systems". |
Initial soil research performed by the U.S. Department of Energy's Oak Ridge National Laboratory (ORNL) is beginning to provide needed empirical data on the significance of carbon building via the introduction organics through our trees' root systems. In eary 2004, soil samples were taken from the CSA site and analyzed at ORNL:
From Un-planted Tree Areas dominated by Cogongrass.
From Planted Areas that had ~2.5 Year-old Trees.
As the below data reflects, soil carbon levels in planted tree areas were between 200% and 300% higher than in soils dominated by cogongrass.
Carbon Concentrations on our Mined Site:
||Soil Depth (cm)
||Average for Cogon Areas
||Average for Tree Areas
Repairing Soils: As below ground organic material is introduced and starts to decay, this initiates a series of soil repairing events that we call a "Genesis Effect".
Nitrogen Concentrations on our Mined Site:
|"Numerous studies have demonstrated that land rehabilitation benefits from plantations because it allows to jump-start succession [of a complete eco-system of plants and wild-life]."|
Soil pH and Available Nitrogen: Re-establishing a relatively neutral soil pH (~6.5) on CSAs is critical -- as this was the soil pH that native plants and trees adapted and evolved to over thousands of years in central Florida. Agriculture science of this fact is well established -- where clearly, native plants such as pine trees and ferns can not live in elevated alkaline soils approaching or exceeding 8.0.
Soil samples at our CSA site reflect that before initial tree plantation development, soil pH was in a range of 7.8 to 8.2 Current soil samples show that pH has been dramatically lowered to a range between 6.5 to 6.8 over a three year period.
The science-based explanation of why the pH of soils at our CSA site has been so dramatically lowered is relatively straight forward. With increasing soil organic matter, increasing levels of bacteria form resulting in the creation of ammonium (available nitrogen to plants and trees). As organic matter mineralizes, ammonium breaks down by nitrosanomum and liberates positive hydrogen ions (acids).
Thus, by the rapid introduction of tremendous volumes of organics into soils (an aspect that planting ~50 trees per acre can not possibly accomplish), the first two dominos to fall in the "Genesis Effects" are:
Reducing soil pH to a neutral level (~6.5)
Increasing available nitrogen to plants and trees.
|"More importantly, some species [of plants and trees] can fix and accumulate nitrogen rapidly in sufficient quantities to provide a nitrogen capital, where none previously existed, more than adequate for normal ecosystem functioning."|
Here again, the ORNL soil analysis is providing extremely helpful empirical data in understanding "nitrogen fixing" on CSA sites -- where nitrogen levels have increased ~1000%.
||Soil Depth (cm)
||Average for Cogon Areas
||Average for Tree Areas
CSA Site Conditions: For most CSAs, site conditions are often characterized by highly compacted soils (bulk density), poor drainage, and dominated by cogongrass. Such harsh site conditions make it extremely difficult if not impossible, for natural succession of native plants to occur on CSAs.
Understanding the problems associated with re-establishing native succession on CSAs is not hard to understand:First, seed banks contained in original topsoils have been
removed as a result of mining.
|"The process of natural succession on surface-mined soils is slow due to the removal of topsoil, resulting in elimination of soil seed bank. There are genuine difficulties in appropriate species reaching a particular site."|
Second, seed introduced by wind or wildlife often can not
germinate in soils characteristic of an asphalt parking
lot in dry seasons or typically underwater in wet seasons.Third, even where seed initially does germinate, the roots
of young seedlings often can not adequately penetrate
highly compacted soil. Fourth, cogongrass produces chemicals that kills
competing vegetation (called an allelopathic effect).
With Plantation Reclamation, the next two "Genesis Effect" dominos that fall are: soil compaction and de-watering.
Based on UF field research, after 3 years from our initial plantation development, soils are now un-compacted to a depth of ~4.5 feet (creation of organic rich topsoils).
Also, standing water on the CSA site is now very rare, even after summer thunderstorms -- where according to UF, the following soil/ground de-watering rates are occurring per acre per year:
65 inches of water, or
1,765,229 gallons of water, or
7,334 tons of water.
Plantation Canopy and New Microclimate: The next "Genesis Effect" domino to fall into place is through the catalytic effect of tree canopy (shading).
|"The development of a plantation canopy can alter the understory microclimate and the soil physical and chemical environment to facilitate recruitment, survival and growth of native forest species. Otherwise, native species would only very slowly, if ever regenerate on degraded sites. Thus plantations may act as 'foster ecosystems' accelerating development of genetic and biochemical diversity on degraded sites."|
Here again, pictures effectively communicate this point where our plantation trees (achieving growth rates of ~20 feet a year) quickly form a forest canopy (1) controlling/eliminating cogongrass; and (2) creating a micro-climate where over 30 species of native flora have now appeared. Natives that appear to be especially thriving on the CSA Tree Farm are Southern Shield Ferns, Creeping Dayflower, Saltbush. and numerous species of native vines.
With the establishment of native plants, the final domino in this "Genesis Effect" is the re-emergence of wildlife (especially bird populations).
|"Ecological restoration [of plantations] concentrates on processes such as persistence of species through natural recruitment and survival, functioning food webs, developing wildlife habitat, system-wide nutrient conservation via relationships among plants, animals and the detrivore community, hydrologic balance in the watershed."|
Florida Phosphate Council.
(2) University of Florida "expected case" estimates for tree yields at our energy crop plantation are 32 green tons per acre, per year. 32 times a typical moisture level of 50% equal 16 dry tons. 16 times estimated below ground tree mass of 60% equals 10 tons of organic matter.
(3) Ammonium converted to nitrate liberates four mols of H+, two mols of ammonium. Specific science-based references for these explanations can be achieved by performing a simple Internet Search (e.g., Google, Altavista, etc.) using target words of mineralization, nitrobacter or nitrosomonis.
(4) Based on results of native plant inventory assessments conducted by UF and the Florida Institute for Phosphate Research.