Humic Acid’s Role in Improving Soil Quality and Plant Growth

Humus and Humic Acid?

The term “humus” dates back to the time of the Romans, when it was frequently used to designate the soil as a whole. It was later applied to the organic matter of soils and composts, or to different fractions of this organic matter; as well as, to complexes formed from a variety of natural organic substances. Humus compounds are complex natural organic compounds that are formed in soils from plant residues, by a process of “humification”. Humus materials are complex aggregate of brown to dark colored amorphous substances, which have originated during the decomposition of plant and animal residues by microorganisms, under aerobic and anaerobic conditions, in soils, composts, peat bogs, and water basins. Chemically, humus consists of certain constituents of the original plant material resistant to further decomposition; of substances undergoing decomposition; of complexes resulting from decomposition, either by processes of hydrolysis or by oxidation and reduction; and of various compounds synthesized by microorganisms.

“Humic acid ” is the commercial term often used to refer to the combined humic and fulvic acid content found in these naturally occurring deposits. Humic acid is known to be among the most bio-chemically active materials found in soil.

Why Use Humic Acid?

Today, there is a recognized and increasing use of humic acids for their beneficial impact on the growth and cultivation of crops (vegetable & non-vegetable), citrus, turf, flowers, and particularly in organically-deficient soils. Humic acid is not a fertilizer as it does not directly provide nutrients to plants, but is a compliment to fertilizer. Benefits include:

• Addition of organic matter to organically-deficient soils
• Increase root vitality
• Improved nutrient uptake
• Increased chlorophyll synthesis
• Better seed germination
• Increased fertilizer retention
• Stimulate beneficial microbial activity
• Healthier plants and improved yields

How Does Humic Acid Improve Soil?

When applied to clay soils, humic acid can help break up compacted soils, allowing for enhanced water penetration and better root zone growth and development. When applied to sandy soils, humic acid adds essential organic material necessary for water retention thus improving root growth and enhancing the sandy soil’s ability to retain and not leach out vital plant nutrients.

How Does Humic Acid Improve Plant Growth?

As mentioned above, one way plant growth is improved is through the structural improvement of both clay and sandy soil allowing for better root growth development.

Plant growth is also improved by the ability of the plant to uptake and receive more nutrients. Humic acid is especially beneficial in freeing up nutrients in the soil so that they are made available to the plant as needed. For instance if an aluminum molecule is binded with a phosphorus one, humic acid detaches them making the phosphorus available for the plant. Humic acid is also especially important because of its ability to chelate micronutrients increasing their bio-availability.

How Does Humic Acid Effect Microbial Activity and What is its Role?

The activities of beneficial soil microbes are crucial for the sustainability of any soil and plant growth. Humic acid stimulates microbial activity by providing the indigenous microbes with a carbon source for food, thus encouraging their growth and activity. Soil microbes are responsible for solubilizing vital nutrients such as phosphorus that can then be absorbed by the humic acid and in turn made available to the plant. Additionally, microbes are responsible for the continued development of humus in the soil as it continues to break down not fully decomposed organic matter. This in-situ production of humus continues to naturally add to the humic acid base and its benefits.

Humic Acid’s Role in Fertilization

Humic acid is technically not a fertilizer, although in some walks people do consider it that. Humic acid is an effective agent to use as a complement to synthetic or organic fertilizers. In many instances, regular humic acid use will reduce the need for fertilization due to the soil’s and plant’s ability to make better use of it. In some occurrences, fertilization can be eliminated entirely if sufficient organic material is present and the soil can become self sustaining through microbial processes and humus production.

Humates in Poultry and Stock Farming

A unique capacity of humic preparation’s is to effectively intensify metabolic processes in vegetable cells.  A series of important scientific tests have shown that this is also evident in relation to animal organisms.  The use of  humic preparations, as part of a food supplements, has been fully researched using highly productive broiler poultry.  It was established that the use of humates in broilers’ feed activated the synthetic phase of albuminous exchange.

As a result, there was a 10% increase in mass growth, and the poultry’s immunity rose by 5%-7%.  In the course of these experiments, soluble humate was added to the feed at 250 mg per 1 kg of feed, starting from the age of twenty days.  In August of 1996, the industrial experiments were carried out together with the Megetskaya poultry farm in the Irkutsk region.  Sodium humate in the form of a water solution containing 1 gram of sodium humate to 1 liter of drinking water was given to chickens from the day they hatched.  This experiment not only confirmed the high efficiency of the preparation, but it also provided new data.

The experiment was carried out on 11,000 chickens under the unfavorable conditions, where the quality of the incubated eggs was substantially below standard.  The results showed that the exchange of vitamins and antibiotics for sodium humate in the feed caused a decrease in the poultry losses for the first forty days by 47%.  At the same time, their average weight gain increased by 10%.

Once more, this data supports the brilliant hypothesis by L. A. Khristeva, who first suggested the high efficiency of the humates under unfavorable conditions.  In 1998, similar tests were carried out on a wide scale at the Severny pedigree poultry breeding state farm near the town of Bratsk.  The results, shown in the following diagram (See Fig. 12), confirmed the previous data.  The poultry losses decreased by 50%, while the active (live) weight in five weeks increased by 30%.

 THE EFFECTS OF HUMATES ON SOIL 

The fertility of the soil was always related to its humus content.  It was determined that humic substances participate in the regulation of most important characteristics.  First of all,  they are accountable for the coloring and, therefore, thermal conditions.  It is particularly important for cold clay soil which under the effect of humates becomes warmer.  Secondly, long-term humate treatment is conducive to the improvement of soil structure.

When humates enter the soil, they form potassium and magnesium humates that bond mechanical element of the soil and act as organo-mineral bridges between aggregates.  Thirdly, one of the important qualities of humates is their ion-exchange activity.  It ensures humates’ ability to regulate the process of  transformation of mineral nutrients in soil-plant system.  Fourthly,  humate treatment increases water saturation of soil.  It is particularly important for sandy soils.  Its water saturation ability increases by more than ten times after humate treatment.  The same principal applies when preparations are used for melioration.  Fifthly, the most important challenge of our times is restoration of the fertility of the soil in suburban zones of the industrially developed regions.  Modern ecological overload makes the soil’s natural self-rectification with micro-organisms insufficient.  Traditionally, organic fertilizers (manure, compost) were used to increase biological activity of the soil and to improve its self-rectification.  However, in spite of high nutritious value of these products, their bond with organic mass is too close, and it decreases their assimilation.  That is why these products are used in large quantities (up to 60-80 ton/hectare).  Introduction of humic substances solves the problem very effectively.

Humic substances determine the structure and the fertility of the soil.  They are an effective measure in solving ecological problems, such as pollution of soil and subsoil waters by chemicals used in agriculture.