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University of Minnesota Extension

Soil organic matter in cropping systems

Increasing soil organic matter (SOM) benefits both crop production and the environment. On this webpage, we share factors that affect the amount of organic matter in soils, and strategies for accumulating SOM while avoiding losses.

Understanding soil organic matter


Role of soil organic matter in crop productivity

The roles of soil organic matter can be classified into three broad categories: Biological, physical and chemical.

There are many and varied interactions that occur between these aspects of SOM, plus the active and stable fractions will play different roles in specific SOM functions.


Effect of agriculture on SOM

The loss of SOM resulting from the conversion of native vegetation to farmland has been extensively studied and is one of the best-documented ecosystem consequences of our agricultural activities.

Agriculture has affected the quality and quantity of SOM on many levels.


Consider all relevant factors—vegetation, harvested biomass, microbial community biomass and plant and microbial respiration—when determining if adding fertilizer will accumulate or degrade SOM.

Laura F. Overstreet, adjunct soil scientist, North Dakota State University and Jodi DeJong-Hughes, Extension educator

Reviewed in 2018

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