Humic substances are organic compounds found in soil, sediment, and water, formed from the decomposition of plant and animal matter. They play a crucial role in soil fertility by enhancing nutrient availability and improving soil structure. These substances are typically categorized into three main types: humic acid, fulvic acid, and humin, each differing in solubility and molecular weight. Humic substances are essential for maintaining healthy ecosystems. They help retain moisture in the soil, support microbial activity, and facilitate the transport of nutrients. Their presence contributes to the overall health of plants and the environment, making them vital for sustainable agriculture and natural resource management.