If you follow practices that build and maintain soil organic matter, especially through the addition of organic amendments, you will improve the quality of your soil, reducing compaction and crusting, and increasing drainage and water holding capacity. Plants will be healthier, may yield more, and will be more tolerant of drought, insects and diseases. You may also need less fertilizer because soil organic matter serves as a reservoir for plant nutrients. This paper describes soil organic matter, how it works to improve the soil, how to build it, characteristics of specific soil organic amendments, their production in Wisconsin, and guidelines for use.