How should microbial biostimulants be used?

Microbial biostimulants are living organisms and require careful management before, during and after application.

Back to: Biostumulants: Function and efficacy

Guidelines for the use of microbial biostimulants

Microbial biostimulants include plant growth promoting bacteria, non-pathogenic fungi, arbuscular mycorrhizal fungi, protozoa and nematodes. Particular care should be taken to follow manufacturer instructions on storage and use.

Management requirements vary depending on the organism used but there are general guidelines that should be followed.

Factor affecting success

Options to manage the risk

Method of production, storage and application

Refer to manufacturer guidelines and consider application method – seed coatings may provide better access to plant roots at early growth stages

Soil physical factors – water potential, temperature, clay content

Unsuitable conditions may reduce effectiveness. Consider soil (e.g. water potential, temperature and clay contents) physical properties at the time of application

Soil chemical factors – pH, available nutrients, pesticides

If unknown, get the soil analysed. Under incorrect chemical environments, the inoculant might not be useful

Competition from indigenous soil microbes

Follow manufacturer guidelines to minimise the risk of competition from the local microbial community

Impact of crop species and management inputs

Understand the needs of the organism you are applying (e.g. oilseed rape cannot form an association with mycorrhizal fungi. A fungal inoculant may also be adversely affected by some fungicides)