Characteristics of a Healthy Soil

Characteristics of a Healthy Soil Foodweb

per Gram (tsp.) of Soil


600,000,000 individual bacteria

15,000 to 20,000 bacterial species

500 to 1000 feet of fungal biomass (150-300 meters)

5,000 to 10,000 fungal species

10,000 protozoa (each consuming 8,000+ bacteria per day equals

480,000,000 parts Nitrogen available)

20-30 beneficial nematodes: bacterial-feeding, fungal-feeding,

predatory. (5 of 100 species considered harmful).

18,600 arthropods per square foot.


Minimum Standards for Compost (for Row Crops),

per Gram (tsp.) of Soil


50-70% -- moisture

2-20 µg – active bacteria

150-300 µg – total bacteria

2-10 µg – active fungi

150-300 – total fungi

10,000 – Flagellates

10,000 – Amoebas

50-100 – ciliates

10-50 – beneficial nematodes


Eliot C. Roberts of The Lawn Institute estimates that there are 930

billion microorganisms in each one-pound of soil under turf.

There are about 70 pounds of them living and working in each

1,000 square feet of root zone. Many of these organisms are very

short-lived, so the turnover is rapid. Roberts says that 100 pounds

of dead microorganisms will contain close to ten pounds of

nitrogen, five pounds of phosphate, two pounds of potassium,

one-half pound of calcium oxide, one-half pound of magnesium oxide, and one-third pound of sulfate. With 70 pounds of these little creatures in each 1,000 square feet of root zone soil, the poundage adds up to enough per acre for excellent crop production.


Reference: Elaine Ingham, PhD.