Agricultural microbiology

Agricultural microbiology is a branch of microbiology dealing with plant associated microbes; soil fertility; plant and animal diseases; microbial degradation of organic matter; soil nutrients transformation etc.

Bacteria - more dominant group of microorganisms in the soil and equal to one half of the microbial biomass in soil. Population 100,000 to several hundred millions for gram of  soil - Autochthnous - Zymogenous groups. Majority are Heterotrophs.  (Common soil bacteria - Arthrobacter, Bacillus, Clostridium, Micrococcus).

Actinomycetes - intermediate group between bacteria and fungi. Numerous and widely distributed in soil. Abundance is next to bacteria. 104 - 108/g soil. 70% of soil actinomycetes are Streptomyces. Many of them are known to produce antibiotics. Population increases with depth of soil. Fungi: More numerous in surface layers of well-aerated and cultivated soils-dominant in acid soils. Common genera in soil are Aspergillus, Mucor, Penicillium Trichoderma, Alternaria, Rhizopus. Algae – found in most of the soils in number ranges from 100 to 10,000 per g. Protozoa: Unicellular – population ranges from 10,000 to 100,000 per g of soil. Most of the soil forms are flagellates, amoebae or ciliates. Derive their nutrition by devouring soil bacteria. Abundant in upper larger of the soil. They are regulating the biological equilibrium in soil.

Importance of soil Microorganisms Involved in nutrient transformation process

Decomposition of resistant components of plant and animal tissue

Role in microbial antagonism

Participate in humus formation

Predator of nematodes

Surface blooming reduces erosion losses

Improve soil structure

Involved soil structure

Maintenance of biological equilibrium