Plant Health and Soil Changes with Humic Substance Applications

Humic substances compose up to 80 % of soil organic matter (Brady & Weil, 2008). Carbon, oxygen, hydrogen, nitrogen, and sulfur are the most common elements in humic substances (Pettit, 2004). As shown in Figure 1, there are three solubility-determined classifications of humic substances; fulvic acid, humic acid, and humin (Pettit, 2004). Humic acids and fulvic acids are soluble in sodium hydroxide