Microbiological Analysis of Soil


Soil foodweb is a commonly used term when discussing microbiological analysis of soil. According to the Michigan Department of Agriculture, “The soil foodweb is the set of organisms that work underground to help plants grow.” There are billions of small life-forms within each teaspoon of soil which contribute to the nutritional vitality and productivity of soil. Soil health is a major focus of organic home gardening.


The soil foodweb approach to agriculture uses microbiological soil analysis as an important assessment tool. Organic gardeners and farmers who practice sustainable agriculture can have soil tested for the level of plant growth-enhancing bacteria and fungi. Other soil organisms include fungi, bacteria, worms, insects, plant-parasitic nematodes and small mammals such as gophers. These tiny organisms create soil’s fertility.


Microbiological activity in soil creates nutrients that give nutritional value to vegetables and fruit. Microbes ingest organic matter in their bodies and secrete nutrients that are taken up into plants. Seventeen nutrients are necessary for healthy plant development, and nutritional value. Soils that are depleted of biological activity from over-use of synthetic fertilizers cannot support biological life.

Microbiological Life

Microbiological foodwebs in soil decompose organic matter for conversion into nutrients. Other functions of the foodweb are redistribution of minerals and nutrients in soil, detoxification of pollutants, modification of soil structure, sequestration of carbon, regulation and suppression of pest species. Testing soil for its microbiological activity is one way to determine its overall productivity.

Soil Tests

Soil tests assess the full foodweb biological activity of a soil sampling, give an analysis of bacterial or fungi content, and test for nematode or protozoa activity. Soil samples are taken of five to 10 places within an area of interest. Core samples from the root area are most representative of the soil’s biological activity. Samples are sent to a microbiological soil analysis laboratory.

Feed the Soil

Compost is the fastest and easiest way to improve soil’s biological activity, according to the California Integrated Waste Management Board’s report on compost microbiology. “The availability of easily usable organic substances enables the proliferation of fastest-growing microorganisms, the bacteria.” Bacteria release heat which helps create the decay process that produces compost. Backyard composting is an easy and efficient way to contribute to soil improvement.

Keywords: soil testing, soil foodweb, soil biology

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."