Soil Tech Note 12A- Soil Organic Matter (SOM)

Soil Organic Matter (SOM)

PROBLEM:  “Didn’t know organic matter was so important.  Think I need more?”

LOW SOM PROBLEM CAUSED BY: 

• Excessive tillage which can cause SOM present to be oxidized or “burned off” as air is mixed with the soil. 
• Low total residue amounts.
• Poor breakdown of surface residues that need to be incorporated into the soil.

WHAT BENEFIT IS GAINED BY ADEQUATE SOM AMOUNT: 

• All microbial life, which affects all plant life, is controlled and determined by the organic matter in the soil.
• Organic matter exudates, such as Glomalin, help to stabilize and glue the soil structure together.
• Organic matter holds organic nutrients that can be released into the soil for uptake by all the agronomic plants we grow.
• Organic matter can hold inorganic nutrients and keep them from leaching out of the soil system.
• Organic matter buffers pH levels. Organic matter buffers surface soil temperature.
• Improves soil resilience to negative soil changes.

POSSIBLE WAYS TO INCREASE SOM IN SOIL:   

• Add Organic Matter to the soil whenever and however you can!
• Reduce tillage and reduce oxidation of the SOM that is already present.
• Cover crops provide an excellent source of both surface and underground SOM.
• Pay attention to C:N ratios in regard to adding straw and other such relatively stable OM to the soil.