Humic Substance Information

January 2010: Vol 5 No 1

Humic substances have been important in agriculture and soil sciences for over 150 years. They can constitute as much as 95% of the total dissolved organic matter in aquatic systems and in many cases they act as a buffering system in lakes and rivers to control the plants uptake of nutrients for sustained growth and development; holds moisture and nutrients in the soil and suppresses the deleterious effect of soil acidity. Humic substances have been documented to interact with over 50 elements that are listed on the periodic table. These substances are formed from the biological and chemical breakdown of animal and plant life, and make up approximately 75% of the organic matter that exists in most mineral soils. Humates can reduce inorganic material and alter the physical production potential characteristics of the soil. The greatest agricultural system should be based on the recycling of organic wastes, which can be noticeable in the form of improved plant growth, because they increase the availability of minerals needed by the plants. Humates can increase the vitamin content of plants, stimulate seed germination and generate a proliferation of root growth with a higher harvest yield, because of the stimulated increase in the uptake of nitrogen, potassium, calcium, magnesium and phosphorus.

Some pesticides may be immobilized by humates. Humates can also help the plants to resist attack from pests. Demonstrations have been done to demonstrate the favorable effects on the plants nutrient balance, fertilizer uptake, top and root growth, and crop yield. Tree top growth, vigor and trunk cross-sectional area is also increased with humate additions. You will see the effects on plants that are grown in soils with less than 2% organic matter. Although, these observable factors have shown results, they are not conclusive. More research is needed to determine the long-term effects on soil and plants. At present, the application of humates to the soil for greater efficiency looks promising and could be better than the present conventional mineral matter application to the soil. Some of the detrimental effects are being seen from the over use of phosphorus and potassium, which cannot be leached out and contribute to the increase in the salinity of soils, which cause the land to be unproductive because of these practices.

Benefits from the application of humic acid derivatives were shown at the University of California along with other U. S. Universities and European scientist as follows:

1. Improves soil physical properties.
2. Holds exchangeable plant nutrients.
3. Improves moisture conditions.
4. Affects the release of plant nutrients through slow decomposition by organisms, especially nitrogen release.
5. Improves trace element nutrition through chelation.
6. Has a growth promoting effect.
7. Has a high base exchange capacity – an important basis for soil fertility concepts.

It has also been shown that humate applications along with a regular fertilizer program can increase shelf life of produce grown when compared with produce grown without humic acid plant feedings. Evidence also shows and increased sugar content in strawberries and Thompson Seedless grapes for raisins. These results show the possibilities for more effective and efficient crop production.

Humus is not a homogeneous substance, but it consists of various complexes that can be readily removed by certain alkaline extraction and other processes (Fulvic is more on the acidic end of the spectrum). It is a 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, usually in soils, composts, peat bogs, and water basins. Humus chemically 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.

At present, there is an increase in the interest of using organic materials as fertilizers or soil supplements. The interest may be a result of the following:

1. The public concern for the potential polluting effects of chemicals in the environment.
2. A decrease in the use of chemical fertilizers.
3. A need for energy conservation.
4. More interest in organically grown food.
5. A desire to have greater nutritional health.

Humic Substance Information Copyright 2010