What is Good About Soil Organic Matter?

Soil organic matter does have many useful functions in soil. Probably the most important is its role in forming and maintaining good soil structure. Simply put, soil structure is just the way the soil particles are put together. Individual soil particles of the clays, silts, and even sands, are quite small. In a soil where these particles remain separate and exist as individual grains of sandsilt or clay, the soil can be hard, resistant to root growth, too wet in the spring because water does not drain away rapidly, and too dry in the summer because, when rains do come, water fails to soak in and ends up running off.

If the individual particles are “glued” together by humus or other cementing agents to form aggregates, a better soil results. Water can enter rapidly through the large pores between aggregates, but is held for plants to use in the small pores within aggregates. Roots can penetrate through an aggregated soil more easily to find water and nutrients.