Particulate Organic Matter

Relationship to Soil Function

As perhaps the most easily decomposable fraction of nonliving SOM after microbial biomass, POM fulfills many soil functions mediated by OM. It is a source of food/energy for microorganisms and soil animals as well as nutrients for plant growth. Particulate organic matter enhances aggregate stability, water infiltration and soil aeration; it increases cation exchange capacity and buffering pH. It also binds environmental pollutants such as heavy metals and pesticides. Particulate organic matter may play an important role in the suppression of soil borne diseases (e.g. damping off of cucumber) by compost. This may be explained by the fact that POM is an important source of food/energy in the compost for microorganisms responsible of disease suppression.

POM and Poor Soil Function

In poorly managed soils, the transport by erosion of sediments rich in POM into rivers and other water bodies can result in alteration of water quality and aquatic life. Build up and mineralization of those organic materials lead to the eutrophication of lakes and rivers. Incomplete mineralization of POM C in very poorly drained soils can lead to the formation of methane, which escapes into the atmosphere and contributes to ozone depletion.

Improving POM Levels

Management that affects SOM accumulation also affects POM content in soil (figs 2 and 3). More POM in the soil means that carbon and other nutrients are being stored in the intermediately available pool and are not subjected to losses (e.g., leaching) yet are available when needed.

The following practices enhance POM levels:

• Tillage management (no-till, strip till, and ridge till)
• Crop rotation, cover crops, and cropping frequency (reduction in fallow frequency)
• Application of manure/compost and organic byproducts
• Pasture and hay land management (e.g., rotational grazing and haying)

This Page Was Created Utilizing Text And Images From These Sources:

Particulate Organic Matter, Soil Quality Indicators Fact Sheet- USDA Natural Resources Conservation Service

Registration Open for 2026 Soil Health Schools!

The Coalition will host two Soil Health Schools in 2026! The West River Soil Health School is set for June 24-25 near Caputa, SD, and the South Dakota Soil Health School is set for Sept. 15-17 near Twin Brooks and Marvin, SD. These events are designed for agricultural producers as well as anyone with an interest in learning how to manage soils for resiliency and profit. The agenda features classroom style presentations by producers and technical experts from across the state and region, as well as hands-on experiences in the field. Area producers will share their challenges and successes with various methods for improving soil health, to an average class size of 30-40. Registration is open, so check out our events page to learn more!