Track 2-11: Plant Nutrition and Nutrient Cycling
Description
Australian soils are inherently low in organic matter. Agricultural practices have compounded this problem. As farmers look for more sustainable farming methods a commercial niche has opened for a range of alternative products including the humic products. More than 200 humic products are manufactured and sold by Australian companies (Billingham 2012). Many more can be purchased via overseas websites.
The term ‘humic products’ denotes a range of materials derived from lignites (brown coals), peats, lignins, composts and other organic wastes. Most are manufactured by alkali and acid extraction of the source material. Humic products are usually sold as soil amendments or foliar sprays under a wide range of trade names and product descriptions in an unregulated market with no standardisation requirements (Billingham 2012). Common groupings are the solid humic acids or humates, the liquid fulvic acids or fulvates and the natural, organic or ‘raw’ humates that have not been extracted with an alkali. The humates and fulvates are often blended with macro and/or micronutrients with the broad claim of increased fertiliser use efficiency. Most application rates range from 5 kg/ha to 1 t/ha for solid products and 1-50 L/ha for liquid products with dilution rates up to 1:200. In 2012 available prices ranged from AU$35 per 5 L drum to more than AU$2500/t (Billingham 2012).
Humic products are marketed with a myriad of claims, but little evidence, of improved soil properties and plant growth. These claims closely resemble the properties of soil organic matter and, especially, the humic substances that occur naturally in soils and are responsible for many of its functions. Very little research into humic products has been conducted in Australia. To determine their efficacy, the peer-reviewed literature was searched and the claims investigated against the evidence found in the literature.
Included in
Humic Products–Potential or Presumption for Agriculture. Do Humic Products Have a Place in Australian Grazing Enterprises?
Australian soils are inherently low in organic matter. Agricultural practices have compounded this problem. As farmers look for more sustainable farming methods a commercial niche has opened for a range of alternative products including the humic products. More than 200 humic products are manufactured and sold by Australian companies (Billingham 2012). Many more can be purchased via overseas websites.
The term ‘humic products’ denotes a range of materials derived from lignites (brown coals), peats, lignins, composts and other organic wastes. Most are manufactured by alkali and acid extraction of the source material. Humic products are usually sold as soil amendments or foliar sprays under a wide range of trade names and product descriptions in an unregulated market with no standardisation requirements (Billingham 2012). Common groupings are the solid humic acids or humates, the liquid fulvic acids or fulvates and the natural, organic or ‘raw’ humates that have not been extracted with an alkali. The humates and fulvates are often blended with macro and/or micronutrients with the broad claim of increased fertiliser use efficiency. Most application rates range from 5 kg/ha to 1 t/ha for solid products and 1-50 L/ha for liquid products with dilution rates up to 1:200. In 2012 available prices ranged from AU$35 per 5 L drum to more than AU$2500/t (Billingham 2012).
Humic products are marketed with a myriad of claims, but little evidence, of improved soil properties and plant growth. These claims closely resemble the properties of soil organic matter and, especially, the humic substances that occur naturally in soils and are responsible for many of its functions. Very little research into humic products has been conducted in Australia. To determine their efficacy, the peer-reviewed literature was searched and the claims investigated against the evidence found in the literature.
