Organic Matter Matters
Peter Newcombe

Spring brings moisture and fluctuation in temperatures, so organic matter matters to fuel resilient turf. Organic matter (OM) is a critical component in soil structure and a food source for the microbes. According to the USDA NRCS, “One percent of organic matter in the top six inches of soil would hold approximately 27,000 gallons of water per acre”. 

Benefits of Organic Matter

  1. increases microbial diversity and activity
  2. helps the soil’s water holding capacity
  3. improves the soil’s ability to retain nutrients

Box Comparison 

from The Art of Balancing Soil Nutrients by William McKibben 

For example, imagine two boxes of completely air-dried soil, each weighing 100 pounds. The first box contains a soil that is 2% organic matter and the second box contains a soil that is 4.5% organic matter. How much water could we pour in each of the boxes before the water would run out?

Approximately 45 pounds of water could be added to the 2% organic matter soil box. On the other hand, almost 150 pounds of water could be added to the 4.5% organic matter soil box. A small increase in organic matter can have a huge increase in water-holding  and nutrient-holding capacity. Therefore, the relationship of the water-holding-capacity to organic matter content is not linear but logarithmic.

Contributing to OM levels

OM is continually being depleted through the normal decomposition process. Consequently, OM needs to be continually added or it will start decreasing. Levels of organic matter can be raised through: the return of clippings, mowing high, organic fertilizer, humates and compost products. The return of grass clippings adds organic matter to the soil. As a result, grass clippings serve as a natural fertilizer equal to one application per season. Healthy soil biology will break down the grass clippings. In addition, mowing high also aids in the production of organic matter. Mowing high encourages deeper rooting of the grass plant. As the roots mature, their ability to absorb water and nutrients diminishes. Eventually the root will die and slough off, adding organic matter to the soil.

In conclusion, healthy soil is a long-term, sustainable need for our earth. Refer to our 10 Steps to an Organic Lawn to promote organic matter within your yard. Remember: organic matter matters!