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Everything You Need to Know About Humic Substance

Everything You Need to Know About Humic Substance

Try planting seeds in pure clay retrieved from the bottom of a 2’ deep hole. There is no plant growth here, no matter how much N-P-K is applied. It is not possible to grow a crop in soil in the complete absence of organic carbon (humus).

In the production of a fertile soil, organic substances play a direct part as they are the sources of plant nutrients which are liberated in available forms during mineralization. The rise in popularity and use of synthetic chemical/mineral fertilizers enabled growers to directly supply plant nutrients to the soil, and rapid growth in agricultural productivity occurred.

As a consequence, the importance of soil organic matter was neglected. Humanity has yet to incur the full brunt of this consequence as population soars and food supply quantity dwindles, and the nutritional value of harvests decreases.

What Do Humic Substances Consist of?

What Do Humic Substances Consist of

No Structure

Humus is a structureless (amorphic) colloidal material resulting from the decomposition (humification) of any type of dead organic matter (mostly plant residues and animal remains). It is a complex mixture including proteins, lignin (plant cell walls); fats, carbohydrates, and organic acids.

These acids, humic acids and chelates, provide a storehouse of essential plant nutrients. It helps make some nutrients more soluble and available to plants. It provides high water absorption and holding capacity and contributes to good soil structure.

It buffers the soil and protects plants from drastic changes in pH. Humus and soil life (microbes and larger creatures) work together for the benefit of all living plants grown in every type of soil.

Organic Carbon

Organic carbon is created from the breakdown of organic matter (usually in the form of crop residues) principally by diverse populations of bacteria, actinomycetes and fungi. The conversion and availability of all mineral elements in soil are related to, and regulated by, this natural system of decay on/in the soil.

This is the environment necessary for the decomposing micro-organisms to flourish. Crop residues are converted into carbon dioxide, carbonic acid and numerous mild organic acids (such as folic acid). These acids, stored in the humus complex, are necessary to convert, chelate, and release soil minerals.

Everyone knows that plants need light, warmth and moisture, in addition to good fertile soil laden with the whole set of macro and micro elements, for plants to flourish (not just ‘survive’). But the real problem is that assimilation of those elements is impossible without some special organic substance, which science calls “humus”. What you buy in a store bag is NOT humus, although it might contain a small amount.

The main compounds in humus are humic acids; which have originated during the decomposition of plant and animal residues by microorganisms, under mostly aerobic (but also in anaerobic conditions), usually in soils, composts, peat bogs, and water basins.

Organic Matter

The importance of organic matter to make soil into dirt is not a recent discovery. Fertility of dirt (sol) in early agricultural systems was based on the recycling of organic wastes. Plowing stubble back into the earth. It was well-known that the addition of decomposed organic materials back into soil improved plant growth.

Besides eventually becoming a source of nutrients for the plant via microbial activity, organic matter has a fundamental effect on the physical properties of the soil (water-holding capacity) and determines to a large degree, such properties as the cation exchange capacity (CEC) and buffering or mediating other soil properties such as salts.

These properties are of great importance, not only in controlling the uptake of nutrients by the plant and the retention of nutrients in the soil, but also in suppressing the deleterious effect of soil acidity and alkalinity.

Effect of Management Practices on Soil Organic Matter.

It is well-known now, that commercial agricultural cultivation of soils usually causes a decrease in the organic matter content and significant effects of erosion and pollution from using synthetic chemicals. For most soils, a high level of organic matter is maintained only by grass species.

Conventional sources of applied organic matter such as farm manures or crop residues are not normally used due to lack of availability or prohibitive cost of spreading them or plowing them under after a poor harvest.

Other Sources of Humic Matter:

Some humate products for agricultural use are produced through mineral sand mining of ancient deposits. The end product contains a majority of organic material (concentrated humic acid) mixed with smaller amounts of mineral matter.

Another product is compost ‘tea’ – the liquid “mirror image” of the compost it is derived from when fresh. If allowed to become anaerobic, microbe populations will decrease, but plant nutrition and humic content can remain viable for many months (even years) if stored properly.

Humate concentrates (such as compost tea from well-managed aged compost) provide many of the advantages of conventional organic matter sources with less handling problems, especially in situations where there is no feasible alternative to purchasing additional supplies of humus such as is found in aged/finished compost. Ancient humic acid deposits in Russia and New Mexico are dwindling, and no new deposits have been located in many decades.

Humates have been demonstrated to have very favorable effects on plant tissue nutrient balance, fertilizer uptake, both top and root growth, crop yield and quality, for a large variety of field and horticultural plants.

If we defined humus as the base of fertility, we can define compost tea products as a concentrate of the vital strength of humus, produced by nature during evolution. The importance of organic matter in soil/dirt cannot be over emphasized. Soil life depends in large part on a steady supply of organic matter. The microbial and larger ‘critters’ in soil all depend, in some way, on the same decomposing organic matter.

What They Are, and Can Do

Humic substance is the end product of decayed matter, and usually contains large quantities of trace minerals. It contains up to 5,000 calories per gram, providing energy that can be used for plant growth.

  • Humates (metal complexes of humic acid) supply growing plants with food. They also make soil more fertile and productive.
  • Humic substance increases the water holding capacity of soil; therefore, it helps plants resist roughts and produces better crops in reduced water conditions.
  • Humic substance breaks up unproductive clay soils, turning them into profitable soils.
  • Humic substance helps retain water soluble inorganic fertilizers, releases them, as needed, to the growing plants, and helps prevent soil leaching.
  • Humic acid stimulates seed germination and viability, and root respiration, formation and growth.
  • Humic acid reduces other fertilizer requirements and increases yield in crops such as potatoes, wheat, tomatoes, corn, beets, etc.
  • Humic substance fosters improved drainage by increasing the porosity of dirt.
  • Humic substance increases aeration by increasing the porosity of dirt.
  • Humic acids increase the protein and mineral contents of most crops.
  • Humates establish a desirable environment for microorganism development.
  • Humic substances produce thicker, greener, and healthier crops.

Effects on Soil Fertility.

Native soil humic substances enhance plant growth both directly and indirectly. Physically, they promote good soil structure and increase the water holding capacity of the soil. Biologically, they affect the activities of microorganisms. Chemically, they serve as an adsorption and retention complex for inorganic plant nutrients. Nutritionally, they are sources of nitrogen, phosphorus, and sulphur for plants and microorganisms. All of these effects increase the productivity of the soil.

Effects on Plants.

Humic acids can have a direct positive effect on plant growth in a number of ways. Both plant root and top growth have been stimulated by humates, but the effect is usually more prominent in the roots. A proliferation in root growth, resulting in an increased efficiency of the root system, is a likely cause of higher plant yields seen in response to humic acid treatment.

Humic matter has been shown to increase the uptake of nitrogen by plants, and to increase soil nitrogen utilization efficiency. It can also enhance the uptake of potassium, calcium, magnesium and phosphorus. Humic and fulvic acids are soluble in water and make available to plants, nutrients and trace minerals that would be otherwise unavailable.

What is a chelate?

Chelates are organic molecules that can trap or encapsulate certain highly reactive trace metal cations which prevent them from entering into unwanted chemical reactions and forming insoluble compounds, which are unavailable.

Chelates incorporate metal ions into a soluble but bound form, to make them available to the plant because they are very soluble in water. Chelation is bonding the metal ion to an organic molecule, making the metal ion highly soluble.

A chelated form of a mineral has different qualities from the mineral itself. One quality that can change is bioavailability; the ability to absorb and use the mineral. Bioavailability can be increased or decreased depending on the mineral-chelate complex formed.

Some synthetic metal-chelate complexes form extremely strong bonds and bind minerals so tightly that they are unavailable for their physiological functions, and if used in foliar fertilizer has a great deal of trouble releasing the metal ion once in the plant.

Metal-chelate complexes used in foliar fertilizers need to form bonds strong enough to protect them from unwanted chemical reactions but once in, the plant should release easily.

Natural chelating agents do not share the problems of the synthetics and are state-of-the-art technology for delivering selected mineral and trace elements with maximum bioavailability, tolerability and safety.

If a yield-limiting deficit is suspected or established then the chelated mineral applied as a foliar will address that deficit more accurately and with greater speed than any other nutrient.

These elements are far more easily absorbed by plant roots and leaves in this chelated form because of changes in the electrical charge from the trace minerals as a result of their organic encapsulation.

The chelation process removes the positive charge from the metals, allowing the neutral or slightly negatively charged, chelated molecule to slide through the pores on the leaf and root surface more rapidly.

These pores are negatively charged, so there is a problem with fixation of positively charged minerals at the pore entrance without chelation. There is no such restrictive barrier for the neutral, chelated mineral.

Humic Substances in the Environment

Humic Substances in the Environment

Soil scientists are still learning how the diverse sets of microorganism populations go about producing humic substances. They know what it is, and what it does – just not a full understanding of how it’s produced.

They know that humic substances can last for millennia – and addition of them into soil/dirt improves quality of soil and plant life. But science has not been able to synthesize it – because it ‘happens’ from plant matter, inside microbes. So far, cannot be replicated by scientific experiment – which means production of humus through composting must remain, for the time being, a science-based ART form.

No two compost piles are alike, and from my experience, no two composters are alike either. But each composter is THE expert of their own pile.

Take special note, that in all this presentation, there are no ‘cautions’ about possible “over usage” of humates. Not even as a foliar spray, although dilutions may be needed to reduce particle accumulation on leaves (which might restrict photosynthesis) if residues from spraying compost tea become too thick. While not likely, signs of such issue should be known to the gardener – and in any case, a quick flush with a hose spray will eliminate any such problem. Humic products are safe to use.

You should know by now, what kind of marvelous results to expect, when applying humic-based products to soil. So if your expectations are not met, you know to look elsewhere for probable causes such as pH or CEC. Or start with addressing a possible fungal issue if symptoms are found on plants.

To determine quality of compost, a variety of measurements and/or testing is recommended. Microbe population diversity and density Carbon content of feedstock Humic substance content Plant nutrient values Oxygen content Temperature Moisture pH And ,any others. Which test, and when to apply a test are qualitative questions – that apply to each individual situation.

But back to the subject – the environment in which microbes can best ‘do their thing’. The internal environment of a compost pile. Microbes have very short life spans. Some only live for less than one minute. So a highly reproductive environment is necessary. Adequate FOOD; WATER and AIR. And minimum DISTURBANCE. But some disturbance is necessary to:

  • Aerate – exchange built-up carbon dioxide for oxygen
  • Moisturize – balancing the air/water ratio
  • Mix – feedstock ingredients (C:N)
  • Cool – sometimes necessary for survival of some microbe populations when feedstock becomes too hot.

What is ‘minimum’?

Again, a qualitative question – that applies to each individual situation. Bacteria need time to establish colonies. Fungi need time to establish hyphae networks. Based on current research, the recommendation is not more than twice monthly – but before oxygen is depleted.

Temperature and moisture content are the two primary ‘indicators’ in this equation – for a newly-built pile. And after the first turn of the pile. After that, monitoring temperature is helpful once some experience is gained, but is no longer a primary indicator. Because mesophilic temperature ranges do not fluctuate to the degree that thermophilic ranges do.

Because of reduced temperature in a mesophilic pile, closer temperature/moisture monitoring is necessary. And keeping good records of measurements and test results.

When to measure or test, also needs to be determined by every expert “keeper of the pile”. Temperature – from the day the pile is constructed, and every 3-4 days thereafter (twice weekly) Moisture – every week.

As a pile progresses in maturity, experience is the main attribute that must be relied on to address issues. That is where a local ‘network’ of people who compost, will become the most important resource for comparisons and assistance with testing.

All network members are encouraged to communicate issues encountered and solutions they applied, along with results. No amount of ‘book learning’ will substitute for practice.

Each network member should be active in assisting other members and their neighbors to learn more about their own composting process. Every compost pile is different. Every member is unique in their understanding of the process and how they go about performing it. Together, we can contribute to the important relationship of proper use of human organic waste disposal issues. Together, we can make a positive impact to improve our community.

What is Humic Acid Used for

What is Humic Acid Used for?

Humic Acid comes entirely from vegetation, and the earliest known forms were created the Carboniferous Period millions of years ago, when the earth’s mineral-richsoils produced a profusion of lush green forests.

As this lush growth of vegetation died, it accumulated at the surface, and later was buried by rock and mudflows and deposits of sand and silt. The weight of these deposits compacted and compressed out all of the moisture. Over the ages, the vegetation underwent compaction and heating. It slowly carbonized and became coal.

Compaction squeezed out the organic acids and esters present in the vegetation and formed a pool on top of the lignite coal bed. This pool dried, aged and eventually formed Leonardite shale. What remains today is a deposit of prehistoric plant derivatives.

During this simple process of decomposition, amino acids, carbohydrates and phenols turned into very complex products called Humic Acids. Because of its vegetative origin, this material is very beneficial to plants today. In natural conditions, humus and its humic acids are not soluble. Otherwise soils could be deprived of humus and eventually washed out to sea.

Humates are the salts of humic acids, which form complexes with phosphorus and micro-nutrition elements which are easily assimilated by plants, and sharply increase efficiency of mineral-based fertilizers.

Humate materials from prehistoric deposits are widely distributed as various organic carbon-containing compounds, found in organic-laden soils, fresh water, and oceans, and make up approximately 75 percent of the organic matter that exists in most mineral soils. Humates play a direct role in determining the production potential of a soil.


Not all the products on the market sold under the name Humus or Humates are not, and of those that do, some are high quality and others are very low. Let the buyer beware, and always read the label information what the product is declared to be. If there is no declaration, the reasonable thing to do is not waste your money.

The more concentrated forms while more expensive, are the best – and in the long run, can be the cheapest depending on usage. There are several different chemical structures of Humic Acid found in ancient deposits, notably mined deep in the sands of New Mexico.

  • fossilized brown oxidized lignite or Leonardite. This product has 30- 40% humic acid content, 30-40% of mineral ash, and the balance is unknown ballast substances. Recommended application norms of these products are very high, because humic acids in them are insoluble and are not in an active form. Mineral content of these products contain metals which bind to humic acids. Long term usage of these products can pollute the soil.
  • produced in the common method of treatment of lignites with concentrated alkalines. The content of Humic acids of these products is within the level of 20-30%. Humates here are in active form, but they still have a high content of ballast and ash, which also causes pollution problems.
  • is produced in the way of treatment of brown lignite or Leonardite with alkaline solutions. These Humates are high quality products, because they are free from ballast, but they are very expensive and difficult to transport and handle. Moreover the production process leaves a lot of waste.
  • Humates produced from a high quality tested lignites, with 70% humic acid content, 12% mineral ash part and 18% organic ballast. These soluble products are in powder form with 75-85% of Humic acids.

Only two products meet those requirements; these come from East Siberia, Russia and N.W. New Mexico; these are freshwater deposits and have the highest percentage of low molecular weight humic acids, generally referred to as Fulvic acids. Fulvic acid is the acid radical found in humic matter which is soluble in alkali, acid, methyl ethyl ketone, and methyl alcohol. Fulvates are the salts of fulvic acid.

Humates In Soil

Both the humic and fulvic (most common form of acids found in soil), resulted from the chemical and biological degradation of dead plant material and the organisms that decompose it.

Humates in Compost

Well-managed aged compost can be tested to determine the level of humic substance that exists. The tests are not cheap, but they are very reliable indicators of how well a compost management system has produced humic and fulvic acids in a given batch of compost.

Fulvic acids provide multiple and natural chemical reactions in the soil, instigating positive influences on the plants’ metabolic processes. Fulvic acid is especially active in dissolving minerals and metals when in solution with water. The metallic minerals simply dissolve into ionic form, and disappear into the fulvic structure becoming bio-chemically reactive and mobile.

The Fulvic acid actually transforms these minerals and metal into elaborate fulvic acid molecular complexes that have vastly different characteristics from their previous metallic mineral form. Fulvic acid is nature’s way of “chelating” metallic minerals, turning them into readily absorbable bio-available forms.

Fulvic acid readily complexes with minerals and metals making them available to plant roots and easily absorbable through cell walls. It makes the actual movement of metal ions that are normally difficult to mobilize or transport. such as iron, easily transportable through plant structures.

It allows minerals to interact with one another, breaking them down into the simplest ionic forms, chelated by the fulvic acid electrolyte.

Fulvic acid is a natural organic electrolyte. An electrolyte is a substance that is soluble in water or other appropriate medium that is capable of conducting electrical current. Fulvic acid has proven to be a powerful organic electrolyte.

Fulvic acids also dissolve and transpose vitamins, coenzymes, auxins, hormones and natural antibiotics that are generally found throughout the soil, making them available. These substances are effective in stimulating even more vigorous and healthy growth through certain bacteria, fungi, and actinomycetes in decomposing vegetation in the soil.

It has been determined that all known vitamins can be present in healthy soil. Plants manufacture many of their own vitamins with those from the soil further supplementing the plant.

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Carlos Warren

Growing up in Texas, I was fascinated by the world of science and invention, thanks in large part to my father's work at Dow Chemical Company. However, my true passion lay in the natural world, and I became an expert in organic gardening and composting at a young age. I spent hours studying the microbiological communities in our family garden, using a microscope to define the quality of the soil. My love for farming and gardening led me to explore new techniques and methods, constantly pushing the boundaries of what was possible.