What is soil organic matter?

Soil organic matter (OM) is the portion of soil that includes plant and animal remains in various stages of decay, and soil microbes.

The functions of OM include:

• Nutrient and water storage. Humus particles are small (colloids), have a large surface area

• Nutrient availability – humus releases nutrients

• Soil aggregation – organic matter causes soil particles to clump together to form aggregates. Better aggregation improves soil tilth and permeability, aeration, water absorption

• Preventing erosion –more water infiltrates in organic rich soils and less water runs off