Humic Substances, Part 6: Applications Of

APPLICATIONS OF HUMIC SUBSTANCES


Humus represents one of the greatest carbon reservoirs on Earth. So far, industrial applications of humus and humus-derived products are rare. On the contrary, the usage of coal was more abundant and essentially, it constituted the basis of the chemical industry in the second half of the 19th century and the first half of the 20th century. Petroleum was also an application and it was regarded as the main raw material for the chemical industry of the 20th century. Nowadays, applications of HS can be divided into four main categories: agriculture, industry, environment and biomedicine.

Agriculture Applications

HS play an important role from the agronomical point of view. They influence significantly the quality and productivity of the soil. In addition to the improvement of the soil’s physical properties and moisture conditions mentioned above, HS also show a high base exchange capacity, which is important for soil fertility (Lotosh 1991, Zhang and He 2004).

Currently, humic materials are used as additives in fertilizers (García et al. 1994, Madejon et al. 2001, Albiach et al. 2001, Kerek et al. 2003, Arancon et al 2004). Different salts of humic substances, such as calcium humate, were used to increase soil fertility (e.g. Buckau et al. 2000). The fertilizing effect of sodium humate on plant leaves has been described. Ammonium humate was also found to have a significant growth-stimulating effect (Lotosh 1991). The characteristics of and applications for humic acids extracted from different compost have also been studied (Ceppi et al. 1999, Madejon et al. 2001, Arancon et al 2004).

The growth-promoting effect of humic substances has been observed by many investigators and humates are often part of different preparations for growth-improvement of plants. Productivity of soil is increased by different ways in the presence of humic materials. The indirect effects of humic substances are very important as they integrate iron to the chelates and make it available to plants. Another role of humic substances lies in the enhancement of the quality of soils when they are very poor in organic matter. Recent research shows that humic acid can be used as farm animal feed thanks to its growth-promoting effect (e.g. Kocabagli et al. 2002).