About Soil

The following sketch of soils was written by Zach Wolf, Field Manager at the Stone Barns Center for Food And Agriculture. If you are not already familiar with soils, this section will take a bit of work to digest. But if you are committed to growing the best food possible it’s worth taking some time to understand the link between soil and nutrition. Zach’s done a great job of it here. Enjoy.

If there are important points that you think we’ve missed or parts that we haven’t articulated well, please let us know. Thanks.


This document is an attempt to share what I have garnered as important principles related to the functioning and maintenance of soil fertility.  I do not claim to have any specific expertise.  I am a farmer and interested in understanding soil from a management perspective.  This being said, a more complete and in depth understand of the processes occurring under our feet does require some basic science.  Further, as soil formation and function are only parts of a larger biogeochemical cycle, we must think holistically, maybe even beyond our immediate soil systems, farm systems and ecosystems out into the cosmos.

The properties that govern soil science begin at the molecular level.   This means we need to understand a bit of physics, as the electromagnetic interactions of atoms in the soil control the soil’s energy.  We need some basic chemistry as this energy translates into the adsorbtion and movement of the soils main chemical nutrients.  And of course, we must understand the role of the soil biology, as these nutrients are hopefully cycled through and released for crop uptake by our soils ecosystem.  If you are up for the trip, some exploration of the electromagnetic influence of father planets upon our soils also deserves some consideration.

The first thing to address in our discussion of soil is its formation.  Roughly, what sorts of rocks have been brought to the surface of this earth that we are working with and by what process did they weather into the clay, silt and sand that make up our soil.  The source and type of parent material helps determine a soil’s natural fertility.  The rock cycle that has formed these primordial soil components is quite complex.  A very simplified version follows:

Our earth’s crust is made of distinct plates that ride on a more liquid (in geologic measures) viscous mantle.  As the plates shift and collide some are subducted down and others rise with uplift.  Sediments from the ocean, collecting millions of tons of soil and minerals and dead ocean bodies are drawn into the earth through this process and metamorphosed by great pressure into new minerals as others are heated and erupted back into the surface of the earth in the form of new igneous basalts.  Soils in New England could have a mix of any of these: sedimentary in areas that were formerly covered in water, metamorphic where sections of mantle have been driven toward the skies or igneous through the work of volcanism.

The most recent event to shape the mixing and distribution of all these ancient rock types has been glaciation.  Here in the Northeast, anywhere north of Long Island where the last glacier extended, has been shaped by the process of glacial till. What this means is that around 10,000-12,000 years ago our last major glacial episode (there have been others) ended.  The freezing and extending and melting and retreating of a glacial mass exerts such a force on the surface of the earth that rocks are transported long distances and literally ground into finer particles.  These events are hugely significant in recharging and circulating a soils mineral reservoir.  The glacial processes, coupled with the amazingly complex geologic history of any given region, means the rock types and soil types can vary greatly across the Eastern United States.  These soil components, the rocks, are further weathered on the surface through physical, chemical and biological forces resulting in the net movement and grading of these parent particles into the sand, silt and clay fractions.

These materials are often graded by size and chemical make up because they were each created by specific processes and contribute differently to a soils structure and function.  Silt is not simply a fine sand and a clay is not simply and fine silt.  Some clay, for example, has a specific layering of alumina and silica crystals that have received a permanent negative charge by the energy received through isomorphic substitution during its formation.  These clays can hold a tremendous amounts of water compared to the other soil fractions, meaning that a clay soil will be slow to drain and easy to compact.  The silt fraction is the greatest source of mineral release for a soil.  This is a good thing.  If we look at a soil’s total possible contribution for our crop we must look at several mineral sources:  those held in solution, those adsorbed by our soils clay or organic matter, those being actively cycled through the organic matter and those being slowly weather out of the silt fraction.  The silt, as compared to the sand, is fine enough to have the acids exuded by plants and microbes actually draw out and exchange certain cations (positively charged ions, pronounced cat-eye-on) for the roots’ hydrogen (more to come on this soon).  Silt then forms the main component of a soil’s mineral reserve and the composition of that soils natural reserve is a gift, one the farmer either needs to manage very little, or one that needs some attention.  Sand in contrast tends to be mineral poor, too large a grade to be weathered at a significant rate for plant use and drains quickly.  A sandy soil will not naturally hold much nutrition or water.  Alone, any of these components in excess will need amending.  However, most soils have a mix of these fractions in a given percentage and are classified a sandy loam, silty loam, or silty sand loam, etc. depending upon the ratio of each.  A visual representation of this classification system can be found easily by web searching “soil texture triangle.”

As we can see already, the history of a soil plays a large part in how fertile it will naturally be, how easy it will be to work and to drain for the farmer.   Fortunately for most Eastern farmers the last glacier prevented the kind of extended leaching that other unglaciated soils face.  Glacial cover prevents vegetation and rain leaching minerals from the soil.  In addition, glacial movement and melt redistributes massive amounts of rock, sand, silt and clay, effectively remineralizing many soils.  Unfortunately, as many Eastern vegetable farmers can attest to, this scattering of significant amounts of rocks throughout our soils also presents obstacles for many of our cultural practices.  Looking at the bright side, soils to our south tend to be much more weathered, more acidic and generally more nutrient poor.  Why?  Because during the centuries that our soils were covered in ice Southern soils were covered in vegetation and enough precipitation to leach from that soil many of the useful minerals needed to grow healthy crops.  In areas of the West and Midwest, the amount of precipitation is slight enough so that much of the mineral content has not been leached.  This difference in climate drives the vegetative patterns of these distinct regions.  In the temperate North and South trees dominate where as in the dryland plains grasses form stable communities at climax states.  In these areas perennial grasses have spent millennia developing and decomposing extensive root systems every year under ground, building a stable organic content of those soils to double or triple that found in the east.  This is coupled with wind patterns that can deposit extensive silt fractions, making some of these soils the most naturally fertile in the history of agriculture.

Of course this mineral component is only a portion of our soils.  Air, water and organic matter make up the other 20, 30 and five percent respectively of a good soil’s composition (these are average numbers and depend on soil type).  What this means from a farming perspective is that soil should have a lot of air, or porosity, and we need to manage accordingly to maintain this tilth in our soils.  Some agronomists actually consider the management of soil air to be the first step, the most important step, toward good stewardship.  Porosity in soil serves many functions.  It allows water to penetrate to roots while bringing with it oxygen which travels into the soil as if attached to this water movement (from a physical perspective it is by capillary action).  This influx of air in the soil literally helps it breath.  Most of the soil biology that we want to encourage is aerobic, meaning it needs air for its survival just as much as we do.  When air is kept out of the soil system the type of biology that predominates can change completely.  Rather than building good soil humus and excreting good acids, these anaerobic microbes tend to produce alcohols and even formaldehyde as a result of their metabolism – two things that can inhibit and even kill roots.  Air in the soil also aids in soil respiration.  Roots produce carbon dioxide, as do soil microbes.  This CO2 is meant to cycle through a healthy soil system, as it has a further purpose of feeding the plant above ground.  It is estimated that plants get the majority of their CO2 from the soil rather from the atmosphere, simply because the concentration in the air immediately around the plant is not sufficient to meet the plant needs during times of maximum photosynthesis.  For this reason also, having adequate organic matter is crucial, as this is the main source for plant carbon.  We can then understand why compacted soils or water logged soils create so many problems.

How do we avoid soil compaction, aid water movement and maintain porosity?  To answer this properly we need to understand two of the most important components of a healthy soil: 1) mineral balance and 2) soil organic matter, or SOM.  And of course, as farmers know, tillage is crucial in this regard also.  But let’s start with mineral balance.

To really understand mineral balance, we need to understand how it is that minerals are held in a given soil.  A favorite analogy of mine is to liken a soils nutrient adsorbtion (defined as the adhesion of charged particles to a surface) to a closet and our mineral content to the clothing in that closet.  The bigger the closet the more clothes I can comfortably fit in it.  In soil chemistry, this closet is known as the Cation Exchange Capacity, CEC.  Cations are atoms with a positive charge.  Most of our base nutrients (I will talk pH, acids and bases later) Calcium, Magnesium, Potassium all carry a net positive charge: Ca++, Mg++, K+.   These cations are the clothes, held in our closet analogy.  The size of our closet and CEC is determined by the amount and quality of clay and SOM we have to work with.  As a rule SOM has a much higher ability to hold cations than clay.  Further, the only way to increase CEC is through SOM and really humus (I will use the two synonymously until I discuss SOM further).

To shake loose a little of the chemistry dust: atoms have a nucleus containing neutrons and protons surrounded by a cloud of electrons that occupy a discrete energy orbit (these electrons can be thought of as particles but truly they behave as waves and particles alike).  The Protons and neutrons contribute to the bulk of the atoms weight and the electrons a negative charge, one for each electron.  This charge is balanced by the positive charge in the nucleus by the protons, the neutrons are neutral.  If we lose one of these electrons, as is often the case when these atoms correct energy imbalances, the atom carries a net positive charge.  If we gain an electron, as is often the case when these atoms correct energy imbalances, the atom is said to be an anion (pronounced an-eye-on).  Both are by the way considered ions, which are any charged atoms.  These charges are significant.  Everything in nature moves through gradients of pressure and charge.  Without charge, without electrical imbalance, there could be no life, which largely utilizes the tendency of nature to create equilibrium and move toward higher entropy and lower energy states.  In farming, we are working with the free energy supplied by the sun and electromagnetic forces.  Effectively, we are trying to control the movement of molecules in a system from low entropy and high disorder toward high entropy and low disorder and then back again.  Highly order ecosystems tend to have low entropy and high energy potential.  Disturbance, land clearing, fire, etc. can breakdown this order and release huge amounts of energy.  This lower energy state has high entropy.  As farmers, as the growing season progresses we create more order, more biomass on our land in our soils and more stored energy in those respective ecosystems.  Once we remove crops or allow them to breakdown we slowly release energy back into these systems and thus increase its entropy.

The most crucial molecule in this process is water.  Water carries a polar charge: both a negative and positive charge, as a result of the hydrogen bonds that form it.  This is hugely important because this means that water can carry both anions and cations through the soil and to the plant.  When a mineral is attached – bonded to either of the poles of the water molecule – and in suspension it is said to be soluble.  The fastest fertilizers are soluble, meaning that the nutrients contained in them are immediately available for the plant to uptake as it draws in water.  This also means that these nutrients can be leached, or brought out of the soil system, just as easily by excess rain.  This is where our CEC comes in.

Clays and organic matter both carry net negative charges.  The charge of clay results primarily from isomorphic substitution within its crystal lattice during formation.  Humus accumulates charge as its organic acids release hydrogen and maintain negative binding site.  This net negative charge is characteristic of most temperate, stable charge soils.  Tropical soils, variable charge soils, can carry both a positive and negative charge and I will not go into those here.  For our purposes, the amount of negative charge is proportional to the number of bonding sites a clay or particle of SOM can hold.  Not all SOM or clays are equal, and the amount of charge on either by weight can vary significantly.  Clays can carry up to 60 CEC while humus can carry charges up to 250 CEC.  The CEC measure that appears on most soils tests is in milligram equivalents (ME).  Basically, what that value is telling us is how much charge, how many negative bonding sites, our soil has.  The standard way soil scientists have chosen to measure this to determine how many 1/1000ths of a gram (hence the milligram) of positively charges hydrogen it take to balance the negative charge of 100 grams of soil.  This value can then be converted based on each ions atomic weight to determine the equivalent amount needed to balance that negative charge.   If my soil has many bonding sites it will have a larger CEC and more potential to hold cations.  Clearly, as farmers are fashionable people in general, we want as many wardrobes as possible and as big of a closet as is practical.  We are then faced with the question of what do we keep in our wardrobe, with what cations do we fill our CEC?  This leads to the balancing part of the equation.

An old, worn soil will tend to have a lot of hydrogen (H+) on its bonding sites, filling its CEC and its closet.  All of this hydrogen makes the soil more acidic.  This acidity is measured by pH (percent hydrogen), which is simply a negative logarithmic scale from 1-14, 1 being most saturated with hydrogen(H+) and acidic, 7 being neutral and 14 being most saturated with hydroxide (OH-) and basic.  At neutral there is an equilibrium presence of both H+ and OH-.   As mentioned earlier, water is bipolar and consists of two hydrogen atoms electrically bonded to on oxygen molecule (H2O).  Certain ions and molecules are considered acids or bases by increasing hydrogen (H+) or hydroxide (OH-) ions.  Acids can increase a solutions net H+ concentration and bases its net OH- concentration.  Plants exchange both H+ and OH- for cations and anions respectively, but most soils tend to accumulate more H+ over time.  As more cations are pulled from either the clay or SOM sites, more hydrogen accumulates.  When hydrogen accumulates the pH decreases, because it is a negative scale, a lower value actually means more hydrogen.  It is worth noting also that because it is a logarithmic scale, a change from 7 to 6 is a change by the power of 10, not just by 1.  To restore these worn soils we add certain cations that replace the hydrogen that has accumulated on our bonding sites.  Depending upon a cation’s size and charge the diameter of that cation when hydrated with water (its hydration radius) will have a lower or higher tendency to fill the soils CEC and replace other cations.  For example, in equal parts, Calcium will replace Magnesium which will replace Potassium which will replace Sodium.  We are filling the closet with new clothes and some take up more space than others.  This is where we get back to soil compaction.

Soil scientists, starting with William Albrecht in the 1940s, studied different soils and found that the ideal ratio of the major cations is as follows: 60-70%Ca, 10-15%Mg, 2-5%K, and trace amounts of Na.  The remainder of the CEC sites will be filled with hydrogen.  These ratios of our major cations are what is referred to as the Base Cation Saturation Ratio (BCSR) for a soil.  We also want some hydrogen in our soil as it helps contribute to the weathering of different minerals in the silt fraction.  The most significant portion of this ration is our Ca:Mg.   More specifically, research has shown that ratios lower than 6:2 tend to push a soil toward being prone to compaction, where as ratios around 7:1 tend to help a soil maintain good tilth and porosity.  Remember the importance of soil air.  This is because the calcium, aside from being arguably one of the most important plant nutrients, flocculates within the soil.  What this simply means is that calcium cations held in the soil align in such a way as to allow maximum air space within that soil.  In contrast, if magnesium levels build too high this property is lost, and the soil can compact.  In addition, farmers have noted that decomposition is hindered in soils high in magnesium.  This of course makes sense, because our ideal microbial community is aerobic, and breaking down the SOM continually.  Once the air to the soil is cut off then this process slows or changes completely.  Hence the formation of hummus and the cycling of the major biologically driven nutrients, Sulfur, Nitrogen, Phosphorus, also slows down.

This brings me to the next point: managing this SOM and our major anion nutrients.  SOM is fundamental in providing a soil with enhanced structure, nutrient mineralization, and nutrient retention.  The way organic matter mixes and adheres to soil particles, forming what is often referred to as a soil colloid; helps integrate air into that soil.  As we keep finding, soil air is essential for many functions.  The soil mineral components, the sand, silt and clays form aggregates or clusters of smaller particles when in a colloid with SOM. These aggregates create the porosity and tilth that I already described as aiding in the water penetration and respiration of that soil, helping our roots and microbes find air, water and release CO2.  In addition, the SOM holds about four times its weight in water, meaning a soil with adequate SOM will be able to moderate runoff and nutrient leaching and also hold and release water to our crops as they need it.  SOM plays a similar role in holding nutrients and releasing them so they are plant available on demand, rather than in excessive flushes that can be lost from the system, as is often the case with chemical fertilization.

To understand this process we need to look at little closer at what SOM actually is: living, dead and very dead organic matter.  In a managed field soil, the living portion would comprise of plant roots and its exudates, the dead portion the active decomposition of that crop, and the very dead the accumulated bodies and acids that are a byproduct of that decomposition.  This is the famed humus we are probably all familiar with.  But not all humus is of the same quality or value for a soil and not all SOM will have equal parts humus.  We are not exactly sure of all of the mechanisms that may be active in any given composting process, which is simplified defined as the controlled breakdown of organic matter and the building up of that material into humus.  It is a two part process and the end results can vary greatly due to many factors.  The composition of the microbial community, the number and diversity of bacteria and fungi present, the quality of the parent organic material, the ratio of Carbon to Nitrogen (C:N), the presence or absence of oxygen during the process, the temperature and duration all create different types of humus.  For our purposes it is most helpful to think of humus as composed of varying levels of organic acids and microbial bodies that are left after these microbes have digested our original organic material.  The main molecular components include fulvic  acids, humic acids and humin and have varying degrees of solubility and can hold a staggering complexity of plant nutrients in their structure.  They also directly coat certain metals, iron in particular, into what are known as chelates.  We can think of these chelates as another way to hold and prevent the leaching of plant nutrients in addition to the CEC already discussed.  To add to our growing closet, these chelated minerals are clothes on layaway, very close by but needed just a little more work on our part to access; they are nutrients that will also not be washed out of our system by the next heavy rain.  In fact, many of our essential plant nutrients can only be held in the soil system throughout the duration of the growing season when they are actively being cycled through the soils biology.

It is the microbial community, the bacteria and fungi that help a plant access and absorb these minerals on demand.  As the living organic matter is converted to the dead portion of the organic matter, minerals that are complexed as organic molecules within those plant bodies are mineralized, and made inorganic by the soil ecosystem.  As soil organisms are consumed those minerals are cycled through the soil food web and released in plant available forms.  Our humus has provided the right habitat for the organisms responsible for this nutrient cycling and sufficient quantities of air and water to maintain their proper functioning.  Within that organic matter the fulvic acids created through the humification process have also accumulated minerals within their framework.  These acids are actually small enough and soluble enough to be directly taken up by the plant roots.  Further, vitamins, amino acids, antibiotics, hormones and a host of other complex molecules are generated by the soils microorganisms and can provide further nutrition, sometimes as the only source, for many essential plant nutrients.  The production of acids through humification further helps to weather minerals out of the silt fraction and the microbes themselves help mobilize cations held in our CEC closet.  Some essential plant nutrients, Nitrogen, Phosphorous, and Sulfer as an example, remain in and are cycled through soils by the soil biology.  Meaning for our plants to have access to a form of Nitrogen they can utilize, we need a healthy population of soil microbes.

This relationship is of course not one sided.  The soil microbiology is also feeding on plant root exudates and in fact depends on the quality and quantity of exudates the plant produces.  In this way, plants can influence the composition of the microbial population feeding within the soil.  Plant roots (an estimated 90 plus percent) also host mycorrhizal fungi that colonizes it and, in essence, extends the range and ability of that root to absorb water and other nutrients within the soil colliod.  In this way, the soil biology and the plant community are involved in a constant feedback: the plants provide the soil community with the products of photosynthisis, while the soil organisms truly rule and exploit the cycling of the soils resources.  In this way, plants are simply the soil microbes’ tool to access the sun, and the soil microbes the stomach of the plant.

The balance of minerals present within a soil is essential for this process to occur at its maximum efficiency.  As William Albrecht famously said, “the microbes eat first,” meaning plant nutrients are first food for the soil biology.  His example of this process was with leguminous crops.  The process of converting atmospheric nitrogen from the air into plant available forms is known as nitrogen fixation.  Many farmers are familiar with this cycle and will be sure to plant a legume grass mix whenever possible: the legume provides the nitrogen and the grass a sink for the absorption of excess nitrogen into its body.  If properly managed, this nitrogen can be made available to the following crop, once it is broken down and converted into plant available forms.  Farmers are also familiar with the need to have adequate calcium in a soil trying to produce a good legume crop.  But it is the Rhizobium – nitrogen fixing bacteria hosted in the legumes root nodules – that demand this calcium more than the crop itself.  In this way, a balance of soil minerals feed our crops but sometimes inadvertently by feeding the right microbes first.

So far we have looked at the components of a productive soil from the perspective of crop management, identifying the importance of:

1)  The source and form of parent materials

2)  The presence of soil air

3)   A balance of soil minerals

4)   An adequate CEC

5)   A robust soil ecosystem.

Perhaps one of the most productive or destructive actions a farmer can take, and a practice that can either enhance or obstruct the balance of these soil properties is tillage, or the active plowing and disturbance of the soil itself.  Tillage can have an effect on each one of these five components of your soil.  Tillage opens the soil to the atmosphere.   For example, deep tillage can help access subsoil parent material, exposing it to air, biological weathering and root penetration.  This process can be helpful when we try to incorporate a cover crop and speed its decomposition.  In this way, tillage can help feed the soil food web.   As we established, anaerobic metabolism has a host of undesirable byproducts we do not want in contact with our roots.  Conversely, an influx of excessive air can “burn up” our organic matter, speeding the process of soil digestion to the point that most of the nutrition we have locked into that material combusts, and is lost to the atmosphere.  What we want is decomposition under aerobic conditions with the right amount of oxygen.  Excess or deficiencies can be problematic.  Overall we have a few different goals in our tillage.  We want a portion of our crop to incorporate into the longer term soil as humus, some nutrients available for our soil organisms to mineralize for our future crops while at the same time creating the right physical soil conditions for that crop’s seeding or transplanting.

The appropriate tillage tool becomes essential.  The old moldboard plow might, for example, do a good job at inverting a sod and in killing that sod, but it also disturbs the soils natural laying and robs the soil of adequate air to property digest that sod.   At the other end of the spectrum, a rototiller will break a sod and incorporate a high level of air, but at times at the cost of the benefits of that material.  If the decomposition happens too rapidly the stored nutrition within that material will not be incorporated into the longer soil nutrient cycle and instead be lost to the atmosphere.  In addition, aggressive tilling can break down soil aggregates.  When a soil loses this structure it is more likely to compact under pressure or when moist.  The soil surface is also more likely to crust over during periods of drought, without the addition of the SOM aggregates for water retention.  Further, a soil without adequate structure under heavy precipitation can crust through the action of the raindrops forcing soil particles together in firmed layers.  Once these layers dry the soil surface can form a hard crust, which further hinders the penetration of water and air.  For these reasons, choosing a tillage system that preserves the soils natural structure, its aggregation, incorporates the right amount of air, and creates the appropriate conditions for the desired use is a fine balance.

By tilling we are automatically going to disturb our soils natural structure, incorporate air and speed soil digestion.  We are farming, we want our former green manures and crops to breakdown after the season and we want the right seedbed for our following crop.  Tillage then is a means to an ends and a compromise.  One must consider the window after tillage as one of increased vulnerability for our soil.  During this time the soil, once it is no longer anchored by a network of roots, can be lost from the system through wind or water erosion.  Again, the type of tillage, the condition of the crop once incorporated, and the season all play a role in how vulnerable the soil will be until the next crop is established.  In the system I work with, one goal is to have sufficient crop residue incorporated into the upper soil layer to help create a porous soil surface and decrease water runoff because rain can penetrate deep into and throughout this surface.  Leaving broken ridges within a soil also helps slow the velocity of water moving across that soil and decreases the removal of soil particles in that water. I think ideally, a tillage system would include two main actions: deep tillage to access the lower soil and light cultivating or discing to incorporate and break up surface residues so they can be digested in the appropriate timing for the next crop.  The emphasis with this method is, again, to not disturb or invert the soil layers but to penetrate the subsoil mineral and water reserve and to incorporate enough oxygen into the soil to aid residue decomposition and humification both.  In these ways, tillage can have some of the most lasting effects on a soils health.

The last area that we cannot leave behind is soil energy.  This is probably the field of most current debate but also one at the forefront of modern soil management.   The potential advantages of better utilizing soil energy are great, but research in this area is not extensive.  My knowledge on the topic is only starting to grow, and I claim, as with all of these pages, to be farmer and not a scientist.  However, leaving this area unmentioned would be leaving out an essential component of building a more whole understanding of our soils.

All soils carry a charge, either positive or negative.  The measure and direction of that charge can vary during the season and depending upon how that soil is managed.  This charge determines how ions are held and how they behave when in contact with the soil colloid and plant root.  Most temperate soils are considered to be stable charge negative, meaning that they favor the retention of cations, as these are positively charged ions that are attracted to the negatively charged colloid, and that the net charge will remain negative.  Some humid tropical soils, those that have high levels of iron in particular, can at times be classified as variable charge soils.  The net current of these soils can vary, being either positive or negative.  Therefore, the AEC (Anion Exchange Capacity) of soils in the humid tropics can dominate as much as the CEC in a temperate soil (temperate soils also hold anions and this should be noted, the difference is the net dominance of a single charge.)  Here in the temperate Northeast, we can assume our soils charge to be net negative, but that does not mean that we cannot manage its current, or should not be concerned with its electromagnetic properties.  I should warn all those who need to verify anything they believe with a scientific reference, some of what follows is a bit of an uncharted territory within scientific and agricultural communities.

Certain solids, depending upon the crystal structures that form them, are classified as paramagnetic or diamagnetic depending upon how they interact with electromagnetic current and field.  The father of biodynamics, Rudolf Stiener, wrote about the balancing of paramagnetic and diamagnetic materials.  He emphasized the ability of paramagnetic materials such as silica to align and draw in the influence of the far cosmic forces: Saturn, Mars and Jupiter.  In biodynamics, these forces are drawn into and moderated by the diamagnetic or repellent materials like lime.  Steiner asserted that lime influences the plant to pull down to the soil its above ground work: the products of what Steiner referred to as aerial digestion or what we might think of as photosynthesis and gas exchange.  Now, I am not a biodynamic farmer, and I struggle with many of Steiner’s ideas, however, let’s not throw the baby out with the bath water.   We just established that the soil needs to draw down energy from the plant: sugars and root exudates.  These are the products of aerial digestion or sunlight and atmosphere, if that term is holding you up.  Steiner also placed an emphasis on the soil clay as a conduit between the flow of the energy absorbed by the paramagnetic materials toward the plant roots.  OK.  So we know our clay and SOM play a key role in adsorbing nutrients for the plant root.  In addition, humus and air are both paramagnetic, further building our healthy soils energy potential.  It seems that what is missing, what we have not covered conceptually already is this what this paramagnetic influence actually is.

Remember, the earth has a magnetic field generated by what scientists believe to effectively be an enormous dynamo in its center, two charged masses rotating and generating a magnetic field.  Now, to remember our atoms from a few pages ago, each of the electrons held on those atoms can be statistically predicated to occupy a specific energy shell.  Each electron is also spinning around its axis while in that shell.  Electrons in the same shell will have opposite spins, clockwise and anticlockwise.  When a material is paramagnetic, it is attracted to and aligns to an applied magnetic field, like the one operating within this planet, or as many would argue that operating in other planets.  To avoid getting too far out, let’s stay on earth for now.  When paramagnetic objects are under the force of an electromagnetic field its electrons experience a magnetic moment, and change spin direction.  This event can actually drive these atoms to align in relation to the applied field.  A classic example of this is a compass point, which aligns toward magnetic north.  Does this phenomenon explain why vegetables grown in the far north, where the electromagnetic field on this earth is greatest, grow to sizes exceeding similar varieties grown to the their south?  Or why roots tend to favor the northern side of a row?

Again, think of the electrons.  When an object is diamagnetic it is also usually diaelectric or acts as an insulator when in contact with electrical current.  In contrast, some paramgnetic materials allow current to pass.  Crystals within paramagnetic objects are at such a spacing that as current passes and excites electrons they are allowed to jump between each crystal’s outer most electron shell.  In diamagnetic materials the crystals are spaced so that electrons cannot jump between electron shells and current is interrupted or blocked.  So, a soil with the right paramagnetic material will tend to 1) react toward and align with an electromagnetic field, and 2) enhance the conductivity or current flow of a given soil.  What does this mean for our soil ecosystem, or the uptake of plant nutrients, or our soil air, lest we forget?  Well, I am not absolutely sure.  What I do believe is that this force is a real, measurable phenomenon within a soil, and its intensity probably plays a huge role in determining the pace of the system.  Scientists have found plants grow faster and seed germination is quicker in soils given a controlled electric charge.  More specifically, if a soil has the right resonance to electromagnetic fields, the flow of ions, the rate of adsorbtion, and all the biological processes within that soil would be at a rate of some proportion to that force.  Conversely, a soil that did not have the appropriate paramagnetic/diamagnetic balance would function, but at a lesser rate, and would not take advantage of all the free energy generated from our earth.  If we create a dynamic electromagnetic balance, the soil ecosystem and nutrient cycling can respond to the varying electromagnetic pulses sent from this and other planets.

Planets in our solar system all emit radiation and tests have shown they can influence plant growth.  Maria Thun, one of the American pioneers of biodynamics, has tested the influence of different planets on plant growth.  Her results are worth investigating.  She and many others have recognized that these forces are inherent, all biology including our crops have evolved with them, and we might as well try to understand and incorporate them into the management of our soils.  Seeds sown during times of corresponding planetary influence – influences on the harvested anatomy of that crop: roots, leafs, flowers, fruits – perform better; have higher yields and resistance to disease and insects.  Why is this?  In Biodynamic agriculture, the soil is said to deeply inhale the collective influences of the cosmos during the winter and exhales these forces through the soil life during the summer.  As far out as this sounds, studies have actually shown that paramagnetic crystals within the earth undergo changes in structure during the winter, altering their alignment slightly while absorbing energy.  As the temperature climbs these structures shift again and energy is released.  If we maintain the right balance of materials in our soils we can maximize the influences of this cycle of inhalation and exhalation: allowing our crops to capture the energy breathed through this earth.

A similar phenomenon that is more widely accepted is the effect of the moon on plant growth.  Just as the moon pulls in and draws out the tides, all water on this planet can experience movement in relation to the force of the moon.  Further, seeds sown in relation to the full moon have shown higher plant vigor and resistance to pests and disease.  This phenomenon has been documented through controlled experimentation.  There is also a long history of its application on traditional farms all over the world.  These ideas might be easy to dismiss, but I encourage everyone who is fully curious about the way our soil works as a system, part of a larger whole that extends into the core of this planet and maybe out into the cosmos, keep an open mind and heart and experiment for themselves.  I have seen the benefits in my own work.

If nothing else, remember that soil is more than the medium to anchor the plant, or a colloid to hold plant nutrients until taken up by the root.  Instead, soil is a dynamic ecosystem, whose function is absolutely dependent upon a myriad of forces: physical, chemical, biological and geological.  As farmers, our plants succeed or suffer in direct relation with the performance of our soil.  Developing a working understanding the soils 1) mineral balance, its 2) biological community, and 3) the electromagnetic influence upon it, is a responsibility of anyone who has the power and intention to dip their plow blade into this earth.



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