Often seen as a complex component of soils for growers, at a very basic level clays are essentially little bits of rock and minerals/silicates. Unlike the previous two major components of the worlds’ soils, clay contains a slight electrical charge, we will discuss the possible fallouts and benefits of this as we progress this blog.
Typically clays contain particles less than 4 micrometers (μm), that’s many times smaller than a sand particle for example. This fine particle size, along with the electrical charge, presents a number of unique characters, and under prepared growers with clay in their spaces will certainly face challenges such as seed germination; poor root penetration and growth; poor water drainage and infiltration & reduced pore spaces. Clay soils can be subject to compaction; swelling; cracking and crusting and swings of pH.
With all of these negatives, it is no surprise to hear people asking questions that help to understand any role bio organics can play in reference to assisting plant growth where growers are faced with heavy clay soils.
Rest assured, whilst there are certain negatives to clay soils, there are also positives, for example, it is forgiving of error, such as the odd over feed and it has excellent nutrient retention. Some clay types suit reduced irrigation and overall nutrient use, and for those that master clay, there is a rich bounty of character to support crops.
Of course we shall cover the challenges and benefits in detail below, but first let us take a look at the origins of clay.
Where does clay come from?
Clays form as a result of the weathering and erosion of rocks, particularly those rocks containing the mineral group feldspar. This weathering of rocks is taking place over vast spans of time and so it is not possible to replace clay within human time frames. As such we need to do everything we can to protect what we have.
During weathering, the feldspar content is altered by the effects of water through a process called hydrolysis, to form clay minerals such as kaolinites and smectites (the principal minerals in the most well known commercial clay, kaoline and bentonite). Wikipedia describes clay as: “a finely-grained natural rock or soil material that combines one or more clay minerals with possible traces of quartz (SiO2), metal oxides (Al2O3 , MgO etc.) and organic matter.
Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Clays are plastic due to particle size and geometry as well as water content, and become hard, brittle and non–plastic upon drying or firing. Depending on the soils content in which it is found, clay can appear in various colours from white to dull grey or brown to deep orange-red”.
Hand testing for clay in your soil
As a rule we can quickly test our growing spaces for the presence of clay and others by performing the ribbon test. Here’s how, simply grab a sample of moist soil, roll it into a ball in your hands and then using a thumb or finger, press in and outwardly on your sample. If the sample breaks and crumbles, we can say that you have very little clay however if the ball stretches into a tape like shape, e.g. resembling a piece of ribbon, then we can say you have clay.
Just how far you can push this ribbon without it breaking up, very much correlates to the level % volume of clay present. Of course to know exactly, you could perform the soil type test we discussed at the start of this blog, but the ribbon test is a quick and easy way to get started with making choices.
So we have decided to go ahead and grow and we know we have clay soil in our spaces, what can we expect and is there anything we can do to improve the quality of the soil and increase the success of our plants from day one?
Working with clay
Unless we know what plants are best suited for clay systems, and there are quite a few, and we are happy to grow this limited range, then to be frank, we can expect losses unless we try to mitigate some of the limitations of growing in heavy clay before we begin.
Many growers have lost faith and interest because of living in a clay dominant soil location but there are some simple tips that can really help to get the benefits of clay and reduce the losses from the outset.
Work that needn’t be done
Firstly, anyone who has, or is trying to dig clay soil will know it’s hard work. The sticky fine particles of clay bind tightly to each other and a shovel full can feel like a wheelbarrow of lead.
Not only is digging it over possibly hurting your back, but its glue like nature means it sticks in clothes to tools and boots, and it’s hard to keep a clean edge making tools dependent on smooth clear sides, inefficient. It’s hard to wash off and clean up too after a back breaking day trying to loosen it up.
All of this work clearing and digging will often be in vain anyway, since the clay will quickly return to its heavy, thick state unless we have added a mass of organic material first, and this can be a challenge on day one. For example, what organic matter, where do we find the organic matter, what are the limitations and so on?
Getting clay to crumble
Compost is an example of organic matter often used to amend heavy clay. It does of course work to improve the quality of clay however it is expensive if you don’t have your own composting facility. It can be a massive hit, and for many agricultural scale operations, it is usually out of the question economically, to layer 6-8 inches of compost across acres, or worse, hectares of land up to twice a year.
Compost teas
Brewing compost teas may provide us with some assistance. Again, correct compost is not as easy as throwing out our kitchen waste with this years lawn clipping into a pile & hey presto an ideal compost appears some time later. Composting is, in itself, an art. Balancing carbon to nitrogen inputs, ensures that we have the relevant biology and that we have sufficient protein content to produce sufficient humates. We will be discussing composting and the making of compost teas later in this blog series.
Other organic matter
Other examples of organic matter that can be used to improve the structure of clay soils, so helping make it better suited to a wider range of crop types, are things like non composted grass clippings, wood chips, animal manures, gypsum and so on. All are again in limited supply in many instances, and often come with the risk of chemical or antibiotic residues, not ideal for those of us following organic methods. Unless you can authenticate (which we highly suggest) that everything is from organic sources, then it’s a minefield.
Domestic home growers in backyards & on housing estates might struggle to access manures and so on, if not, then perhaps rural farmers who might struggle to get enough.
Better Organix does of course still recommend that, where we can, we should mulch clay soils with limitations and, as ever, we have been working to find both human practice and biological solutions, that mitigate the limits of clay soils.
Mycorrhizal fungi
At BOX HQ, the go to question stream is typically something like this, why does that happen? Followed quickly by, what does nature do, that we do not? Biologically, natures immediate answer to growing in clay is mycorrhizal fungi, and so this is also the lead component of the clay puzzle for Better Organix in our Root Better.
Where tightly packed clay soils present a problem for many plants, especially seedlings, and/or juvenile transplants with smaller root systems, we see that plants successfully inoculated with mycorrhizas, have a much greater probability of success.
Moreover, mycorrhizas release glomalin, this is an amino acid rich substance, and given that humates are a creation of soil chemistry, itself dependant on amino acids as essential building blocks, we can use Root Better to build the very humates that will improve the top soil for plant growth Mycorrhiza fungi, found in Root Better and globally in healthy, undisturbed soil systems, have ultra fine mycelium, a type of root structure for the fungus.
This fine but highly charged and penetrative mycelium, is able to track and bust with immense force into the minuscule pore spaces between clay particles. The symbiotic fungus begins mining parent nutrients from the clay surface, and water trapped between the clay structure, and passing this between the plant and the root based biome of bacteria, protozoa, viruses, yeasts and so on, who then all mobilise to improve the local conditions, and provide direct benefit to our plants via a huge increase in metabolites, used by our plant, to reach its true potential in the otherwise harsh conditions of heavy clay.
So, while others are busy trying to collect organic matter to mulch the clay to improve its structure, we can get going on increasing available biomass, by always using Root Better when we plant up in clay soils. Simply, Root Better allows us to grow healthier plants, that are, if required, the basis of tomorrows’ mulch and so we think it’s the go to option, for combating clay and getting growing on day one.
Root Better can be seen as a solution to reduce the risk of compaction. There are various factors which cause soil profile collapse, of course we can immediately think of the obvious, say traffic by machine, animal or human, another way we can suffer profile collapse in soils with clay, might be via the over application of synthetic or organic cation based nutrients. For example, any nutrient has a positive charge, there are many, some we can use as part of a mitigation system for our advantage, but others cause an increase in stickiness of the clay.
The positive side of the negative charge of clay
Clay has a light, negative charge, this means the surface of any clay particle is held away from its fellow/neighbouring particle since each one is, by nature in most of the world, negatively charged. Now, because the particles are fine, this gap between each is small, hence too small for most roots, but not for our Root Better mycorrhizzas, as we heard earlier however where we choose not to use Root Better and we apply a heavy dose of fertiliser, we find any positively charged ion is being attracted to the surface of the clay. Here cations can bind to sites on the clay surface and this means a few things:
· Clay can hold far higher higher levels of many desired plant growth nutrients (cations) such as calcium, magnesium, potassium & sodium.
· It can hold onto acid forming positive ions, hydrogen and aluminum and these can cause acidification.
· If overfed, it can adsorb a large number of excess nutrients the surface charge can change, altering the natural balance of the clay in a system.
The negative side of the positive charge of clay
The initial negatively charged clay now possesses a positive signal as the surface is overloaded with cations and these clays begin to attract their neighboring particles of opposite charge, this binds the clay into ever tightening platelets, squeezing out any oxygen, driving out aerobic microbes, reducing water infiltration, root penetration & nutrient uptake, all bad markers for most plants
· As conditions continue to worsen, water trapped by collapsing clay, now depleted of oxygen, goes anaerobic. The conditions drive pH down into the lower acidic levels, making many harmful metals mobile in the soil solution, while making plants unhappy and exposed to wider risks associated with a lack of critical nutrient access
Common responses\treatments such as liming, to combat pH climb, are simply compounding the collapse of the system through the addition of more positive charged cations, therefore temporary pH effect is countered by the compaction of lime bands in over treated soil profiles.
Uprooting the damage
Root Better with its powerful mycorrhiza fungi and partnering biome of microbes, helps reduce the risk of compaction by scavenging nutrients from clay and those free radical ions in the system. Storing them both on their own negatively charged bodies, using them as food, and further, to generate powerful metabolites and soil antibiotics for pathogen suppression, compounds that up-regulate our plants ability to resist stressors like drought, high UV, insect, fungal, bacterial and viruses otherwise relating to pathogenic attack.
The ability for microbes to store ions on their person, greatly reduces the stress on clay, preventing the excess cations from overloading the slight negative charge, or where excess ions have already caused damage and profile collapse, then remediating the entropic state of clay.
This reversing of past damage, assists in the prevention of an accumulation of radical ions from causing acidification thus unblocking many key nutrients that require more neutral conditions to be fully available. This mechanism also helps to prevent nutrient
loss through leaching, and reduces pollution risks associated with eutrophication.
As well as the neat trick of storage, mycorrhizas, soil fungus and the related biomes of bacteria, protozoa, beneficial yeasts and so on, all have the ability to determine soil aggregation and so are largely responsible for building soil structure, which they do in the best interests of their plant hosts. Fungus can ball up clay, with sands, silts, organic matter, humates, mineral rocks, entire communities of bacteria, water molecules, coating them with a protein called glomalin. This constructs sustainable, plant ready soil profiles, equipped with all the components required for healthy roots and to deliver nutrients to our plants.
By establishing the presence of mycorrhizas through applications of Root Better, we are ensuring the beginning of the transformation of clay soils, that bolsters our efforts where we have applied mulch, through the inclusion of both decomposing and humidifying microbes, thus giving a kick start to the conversion of organic matter, enabling the journey from heavy clay to a nutrient rich, plant root friendly, growing medium. Bio Media Pro can be used to replace Root Better on all non mycorrhizal associative annuals grown in clay soil.
It contains many specialist bacteria and soil yeasts, molds and DSE type fungus such as trichodermas, that work collectively to improve the conditions for mostly everything we grow for food.
Microorganisms in Bio Media Pro secrete compounds and proteins which work to aggregate clay particles, technically tilling the soil from within by opening up pore spaces, creating channels for both water, air and roots as well as mobilizing nutrients previously locked up in the composition of clays, and/ or out of reach to roots unable to penetrate its lattice.
The life in Bio Media Pro is able to draw down the organic matter we are heaping on to clays and speed up the process of altering the structure of heavy clays, helping to build the matter we apply in to a more friable system (more easily broken into small pieces).
The conversion of organic matter is a time and labour consuming process, and because of this, it’s riddled with challenges, especially for organic growers.
Problems such as, provenance, mean we are often left with choices, to apply or not. We, at Better Organix have also studied the impacts of humus on heavy clay soils and looked for alternative methods that might allow us to knowingly take advantage of the benefits offered by stable, traceable and measurable humus. This has led us to Bio Balance Media and Bio Balance Foliar.
Bio Balance Media is a highly concentrated blend of Humic Acid and is used on most soil systems, Bio Balance Foliar is more often used where soil conditions lean toward the acidic, and plant choices demand this state is maintained.
Without going into too much detail about each product at this stage, we want to keep this blog focused on the impacts of humates, humic and fulvic acids with reference to soil.
In healthy soil, biomolecules of humus (decayed organic matter) help retain water and the ionized nutrients that are produced by the natural cycling of organic biomass, compost, or other sources of fertilizer. This makes them a valuable assistant for us growers, especially in clay conditions where organic matter is often at its lowest, especially where we also have higher soil temperatures, and this heat greatly increases the rates of decay and often losses of our added organic mulches and so on, meaning repeat applications are often required, this is both resource and labour intensive. Conversely, where we have cooler environmental conditions, we see a slow down in the rate of conversion of organic matter, so its impacts on application are barely noticed.
Here we can use the character of Bio Balance Media to darken our soils, thus helping them to absorb more sunlight/UV energy, this in turn warms the soil, improves conditions for microscopic organisms and so speeds the rates of metabolism among our living micro biome, to better suit fast growing crops. This thermal change in our soils’ profile allows us to take better advantage of any applied biomass or fertiliser.
What does humic acid do?
Right now let’s have a look at the the physics of humic acid, since this will help us better understand why it’s a beneficial addition to our growers tools. Humic acids are awesome donors and hosts of vital plant growth nutrients.
They work to balance the complex dance of electrical charge in our soil systems. An easy way to visualise them, that works for us here at BOX, is to imagine the compound as having many pairs of hands which it can use to hold onto and reach out and attract many of the things our plants and soils systems need. They are complex and long compounds which can boost the cation capacity of our soils, attract water, radical ions and better still, hold onto these things, wrapping them up amid the many anchor points, so preventing their loss. They are electronegative; which means they can lock onto positively charged ions and molecules. This helpful character means they are always attracted to the depletion zone of the plant root where they seek to balance levels of nutrients which are used by our plants; they also clean up any excess radical ions, released by our plants in to the soil system as they respire.
This really cool trick means that beneficial cations are presented to our plants roots, and that radical ions are scooped up and locked away, either from forming non available compounds with other vital plant growth nutrients, or from over accumulation on the surface of our clays, which can otherwise be a major contributing factor to soil profile collapse and compaction, or pH swings, e.g. acidification.
As our plants feed, nutrients within the immediate vicinity to our roots, are constantly diminished. Any plant not connected to symbiotic root fungus and bacteria, can quickly suffer in heavy clays. The roots simply can’t reach newer sources of nutrition and/or water.
Humic acids can help alleviate the problems of depletion. Positive ions (cations) are attracted to plant roots through a negative charge. Bio Balance Media holds onto cations and presents them in such a way as to make them more available to plant roots. This process is known as chelation, a word which literally means ‘to claw’.
Summing up
This truly is a battle of the charges, with the plant root charge being stronger than that of the humic substances and the clays, thus if you like, our plants can pick the pockets of humic acids like those found in Bio Balance Media, taking the ions of nutrients and also the water molecules wrapped up in the chains for themselves.
Through the process of chelation, nature is helping our plants by preventing often volatile elements, calcium, magnesium, iron and so on, from binding into forms unavailable to plants.
Just as humic acids like Bio Balance Media help maintain plant growth micronutrients in a ready state, so it is also true, that soils rich in humic acids can hold up to 40 times more water than those systems devoid of sufficient humates.
We can now see how applications of humic acids can greatly improve drought tolerance, as well as allowing our plants better access to many micronutrients, critical for the creation of enzymes etc that are needed for healthy plant growth. Bio Balance Media not only boosts the performance of our plants, but it also provides this benefit to our recently applied Root Better mycorrhizal inoculates as well.
As mentioned previously, compost and other sources of decomposing organic matter are not an efficient way to build soil humus levels in certain conditions. In high heat, high moisture, compost rapidly decomposes and leaves its minerals behind, releasing carbon into the atmosphere as CO2. Humic substances such as Bio Balance Media and Foliar, on the other hand, are stable, long lasting biomolecules.
If you need to fix or rehabilitate a soil, increase its nutrient holding capacity, improve its structure and porosity and improve water availability, & thereby making that soil healthier for all plants, roots, microorganisms, then you can depend on Bio Balance Media and Bio Balance Foliar.
When used in conjunction with Root Better, Bio Media Pro, as an integral part of our range of dual purpose liquid biostimulants and plant nutrients, becomes part of a powerful, naturally based system that has been the basis of soil construction since the dawn of time
There are literally hundreds of research papers found online to help uncover the full science behind applications of living biology and critical soil substances like Bio Balance Media reference its application on clays and other soil types.
Each of our products could form the basis of a book on their own and in this blog we have only just scratched the surface. In time we will of course cover each product and any conditions they favour in more detail, but for now, happy growing.