BIOINOCULANTS (or) MICROBIAL INOCULANTS - AN INTRODUCTION

Microbial Inoculants (or) Bioinoculants

• Current agricultural practices depend heavily on Chemical inputs such as Fertilizers, Pesticides, and Herbicides which, all things being equal cause a deleterious effect on the nutritional value of farm products and the health of farm workers and consumers.  A reliable alternative to the use of chemical inputs is microbial inoculants that can act as biofertilizers, bioherbicides, biopesticides, and biocontrol agents.
• Microbial Inoculants are also called Bioinoculants or Soil Inoculants.
• Microbial inoculants refer to formulations composed of Beneficial microorganisms (bacteria, fungi, and algae) that play an important role in soil ecosystems for sustainable agriculture.
• Microbial inoculants are gaining importance for attaining sustainable agricultural production systems. An increasing trend for the use of microbial bioinoculants to accomplish sustainable agriculture has been witnessed across the globe.
• Microbial Inoculants include beneficial microorganisms which form a symbiotic (mutualistic) relationship with the target plants.
• Microbial inoculants are beneficiary microorganisms applied to either the soil or the plant in order to improve productivity and crop health.
• Microbial Inoculants are able to carry out Plant growth promotion (Biofertilizers), Pest control (Biopesticides), and Plant disease control (Biocontrol agents).
• Microbial inoculants have the ability to minimize the negative impact of chemical input and consequently increase the quantity and quality of agricultural products. Microbial inoculants are eco-friendly and deliver plant nutrients to plants in a more sustainable manner. Microbial inoculants can help to reduce chemical fertilizer application.  

Types of Microbial Inoculants

• Nitrogen fixing bacteria – Azospirillum sp., Rhizobium sp., Azotobacter sp., Achromobacter sp., Gluconacetobacter diazotrophicus, Azorhizobium sp., Sinorhizobium sp., Frankia sp., Azoarcus sp., Mesorhizobium sp., Allorhizobium sp., Bradyrhizobium sp., Burkholderia sp., and Herbaspirillum sp.
• Phosphate solubilizers – Pseudomonas sp., Bacillus sp., Arthrobacter sp., Rhodococcus sp., Serratia sp., Gordonia sp., Phyllobacterium sp., Delftia sp.,    Azotobacter sp., Xanthomonas sp., Chryseobacterium sp., Enterobacter sp., Pantoea sp., Klebsiella sp., Xanthobacter agilis, Vibrio proteolyticus and Rhizobium leguminosarum.
• Phosphate mobilizers – Mycorrhizal fungi
• Biocontrol agents – Pseudomonas fluorescence, Bacillus subtilis, Trichoderma viride, Trichoderma harzianum and Pochonia chlamydosporia.
• Biopesticides - Entomopathogenic bacteria (Bacillus thuringiensis and Paenibacillus popilliae); Entomopathogenic fungi (Beauveria bassiana, Metarhizium anisopliae, Isaria fumosorosea, Lecanicillium lecanii, Purpureocillium lilacinum, Entomophaga sp. and Neozygites sp.); Entomopathogenic virus (Helicoverpa zea Single-enveloped Nucleopolyhedrovirus - [HzSNVP], Spodoptera exigua Multi-enveloped Nucleopolyhedrovirus [SeMNPV,] and Cydia pomonella Granulovirus [CpGV]).
• Effective microorganisms (EM) – Mixture of Photosynthetic bacteria (Rhodopseudomonas palustris) + Lactic acid bacteria (Lactobacillus casei) + Yeast (Saccharomyces cerevisiae) + Other beneficial microorganisms existing in the environment.

Importance of Microbial Inoculants to plants

• Improves plant nutrition and promotes plant growth.
• Stimulates the production of Plant growth promoting hormones (Indole acetic acid and Gibberellins)
• Manage soil biology, soil structure, and organic wastes
• Manipulate the Rhizosphere and Phyllosphere region of plants.
• Induce Induced Systemic Resistance (ISR), Systemic Acquired Resistance (SAR), and Integrated Pest Management (IPM).
• Enhances plant production and protection.
• Recycling of vital elements through the Biogeochemical cycle.
• Suppress the Soil borne pathogens.
• Reduces the concentration of toxic substances including Pesticides and Heavy metals in soil.
• Enhances the Photosynthesis process in plants.
• Promotes Germination, Flowering, and Fruiting in plants.
• Fixation of atmospheric nitrogen.
• Solubilization of Insoluble nutrients in the soil.
• Mobilization of various soil nutrients in the soil.
• Prevent plants from Phytopathogens and Insect pests.
• Produces polysaccharides to improve Soil aggregation.
• Prevent plants from high temperature, salinity, and desiccation.