Summary. Microorganisms abound in the soil and are critical to decomposing organic residues and recycling soil nutrients. Bacteria are the smallest and most hardy microbe in the soil and can survive under harsh conditions like tillage.

What is the role of microorganisms in soil?

Collectively, soil microorganisms play an essential role in decomposing organic matter, cycling nutrients and fertilising the soil. ... It must be stressed that microbes generally exert little influence on changing the actual physical structure of the soil; that is performed by larger organisms.

What do microorganisms do for plants?

Beyond nutrient cycling, microbes produce hormones and other chemicals to stimulate plant growth. Soil microbes can also prevent pathogen infection by inducing plant systemic disease resistance and by coating root surfaces to physically shield the plant from getting infected by pathogens.