Soil health is not soil fertility alone. All cultivable soils harbor both useful and harmful organisms. When soil-borne fungi, bacteria, nematodes, protozoa, are present, individually or in combination, above the threshold level, it is called ‘Sick Soil’. Hence, all fertile and productive soils need not necessarily be ‘healthy soils’. All healthy soils need not be fertile and productive either. Several soil-borne pathogens like Fusarium, Rhizoctonia, Verticillium, Phytophthora, Pythium, Meloidogyne, Heterodera, etc., thrive well in certain soils and cause severe crop diseases. Such soils are called Conducive soils. Whereas, the same pathogens develop much less and cause milder disease in certain other soils called the Suppressive soils. In most cases the primary reason for a soil being suppressive is the presence of one or several microorganisms antagonistic to the pathogens.