The International Humic Substances Society (IHSS) is a scientific society that seeks to advance knowledge and research of natural organic matter

Organic matter

Organic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...

 (NOM) in soil

Soil

Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 and water. It was founded in Denver, Colorado

Denver, Colorado

The City and County of Denver is the capital and the most populous city of the U.S. state of Colorado. Denver is a consolidated city-county, located in the South Platte River Valley on the western edge of the High Plains just east of the Front Range of the Rocky Mountains...

, USA, on September 11, 1981 by scientists who saw a need for a society to bring together scientists in the coal

Coal

Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

, soil, and water sciences with interest in humic substances, and to provide opportunities for them to exchange ideas. Currently the society has about 900 members.

The IHSS maintains a collection of standard and reference samples of humic

Humic acid

Humic acid is a principal component of humic substances, which are the major organic constituents of soil , peat, coal, many upland streams, dystrophic lakes, and ocean water. It is produced by biodegradation of dead organic matter...

 and fulvic acids from lignite

Lignite

Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...

, fresh water, a mineral soil, and organic soils plus reverse osmosis

Reverse osmosis

Reverse osmosis is a membrane technical filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane and...

NOM from fresh waters that has not been fractionated. These material are used by research scientists around the world. The IHSS convenes biennial international conferences, which bring together scientists from the soil, coal, freshwater, and marine sciences.