How much organic matter is enough?
Unlike the case with plant nutrients or pH levels, there are no accepted guidelines for organic matter content. We do know some general guidelines. For example, 2 percent organic matter in a sandy soil is very good, but in a clay soil, 2 percent indicates a greatly depleted situation. The complexity of soil organic matter composition, including biological diversity of organisms as well as the actual organic chemicals present, means that there is no simple interpretation for total soil organic matter tests. Using Organic Materials Crop residues. Crop residues are usually the largest source of organic materials available to farmers. The amount of crop residue left after harvest varies depending on the crop. Soybeans, potatoes, lettuce and corn silage leave little residue. Small grains, on the other hand, leave more residue, while sorghum and corn harvested for grain leave the most. A ton or more of crop residues per acre may sound like a lot of organic material being returned to the soil
