Humic substances, those containing carbon such as humic acids, are the primary organic compounds found in humus, the major organic fraction of soil. The addition of humic acids can be beneficial for soils and plants by doing two primary things; improve the soil’s holding capacity and help plant roots receive water and nutrients. Because of the high level of organic compounds found in organic matter, humic acids tend to work better on lower soil organic matters, or where increased water and nutrient holding capacity is desired.