Percentage of Organic Matter in Soil


The University of Minnesota Extension says “improved organic matter management may be the most significant thing you can do to improve soil.” The degraded soil conditions that result from overuse of synthetic fertilizers are a contributing factor to world hunger problems and to lifeless soil in home gardens. The percentage of organic matter can be increased in several ways.


Soil organic matter has three parts: living organisms, fresh plant and animal residue, and well-decomposed residue. The well decomposed residue is called humus and it consists of plants and animals that decayed long ago. Fresh residues are the primary source of food for living organisms in soil. Nutrients are created by living organisms and released into the soil. The soil’s nutritional content is thus increased.

Job of Organic Matter

Organic matter provides the pool of nutrients for growing plants. It also increases water retention and decreases water evaporation in soil. The percentage of organic matter in soil improves plant’s root structure by giving roots a place to hold. It binds nutrients so plants can absorb them as needed. Organic matter also prevents soil from becoming impacted and clay-like.

Amounts Needed

Soil tests are needed every few years to assess deficits and excesses. Organic matter can be added as a soil amendment to increase nutrient levels. Percentage of organic content in soil can range from .05 to 8, with optimum levels in the middle. If soil is fertile, does not erode or wash away, supports plant life easily and retains water well, it has an adequate percentage of organic matter content. Healthy soil is also crumbly and falls easily out of your hand.

Increase Organic Matter

Reduced tillage can help farmers improve their soil. Other recommendations are to grow cover crops for green manure and to continually add composted materials to the soil. Rehabilitating agricultural land is a major focus of sustainable farming and home-garden organic growing.

Improve Your Soil

It takes up to 500 years to create 1 inch of topsoil, according to the U.S. Environmental Protection Agency. The percentage of organic matter in home garden soil can be increased by adding homemade or commercially available compost regularly. The “no-till method” of adding layers of green material residue to the garden is recommended by the American Dahlia Society. The “no-till method” also increases the percentage of organic matter in soil.

Keywords: soil improvement, organic matter content, organic soil

About this Author

Joan Norton, M.A., is a licensed psychotherapist and professional writer in the field of women's spirituality. She blogs and has two published books on the subject of Mary Magdalene; "14 Steps To Awaken The Sacred Feminine:Women in the Circle of Mary Magdalene," and "The Mary Magdalene Within."