Why is Soil Organic Matter so Important?

What makes one field more productive than another?soil organic matter

As you evaluate the productivity of your field, what characteristics make it more valuable than another? There are many things that contribute to a fields’ overall productivity, soil health, drainage, fertility, etc. But soil organic matter seems to be most common in highly productive fields.

So what is soil organic matter?

To give a simple explanation, it is plant and animal tissue that is in various stages of decomposition. Humus, one form of organic matter, is the when the decomposition process is complete. Much of organic matter is plant residue like leaves, stalk and roots. There is also a good portion that include the soil biological organisms and the exudates they feed on. And finally, there is humus. Organic matter is measured in percent of the soil. Many Midwest soils will have somewhere between 1-7% organic matter. This is greatly influenced by the soil types it resides in, the average days of decomposition, temperature, rainfall and many other factors.

What are the benefits of soil organic matter? Below are the physical, chemical and biological benefits of organic matter, courtesy of Cornell University Cooperative Extension:

Physical Benefits

  • Enhances aggregate stability, improving water infiltration and soil aeration, reducing runoff.
  • Improves water holding capacity.
  • Reduces the stickiness of clay soils making them easier to till.
  • Reduces surface crusting, facilitating seedbed preparation.

Chemical Benefits

  • Increases the soil’s CEC, or its ability to hold onto and supply over time essential nutrients such as calcium, magnesium and potassium.
  • Improves the ability of a soil to resist pH change; this is also known as buffering capacity.
  • Accelerates decomposition of soil minerals over time, making the nutrients in the minerals available for plant uptake.

Biological Benefits

  • Provides food for the living organisms in the soil.
  • Enhances soil microbial biodiversity and activity which can help in the suppression of diseases and pests.
  • Enhances pore space through the actions of soil microorganisms. This helps to increase infiltration and reduce runoff.
    Megan Fenton, Carl Albers, Quirine Ketterings 2008

As you can see, increasing soil organic matter will benefit the soil and the crop it grows in. What if you could increase your organic matter; how would that improve the value of your land? I have said it many times when it comes to land rentals, if you can increase production, you can increase the land’s value. Next week I will share with you some strategies to conserve and build organic matter. Just remember, building organic matter is not a quick and easy process. Working with the right farmer who can implement this strategy as a long-term plan is a key piece of the plan.

Leave a Reply