The document discusses the roles and benefits of composting organic materials. It explains that composting is the process by which organic matter such as plant and animal waste breaks down into a nutrient-rich soil amendment called humus. A variety of micro- and macro-organisms assist in decomposition. Regularly turning compost piles aerates them, speeds up the process, and produces higher quality compost. Applying compost to soil improves its structure, fertility, and ability to retain water and support plant growth.