Biostimulants are increasingly available and are now widely marketed to farmers. While the jury is still out on a definitive definition, most definitions of biostimulants explain that they should stimulate plant nutrition processes independently of the product’s nutrient content with the aim of improving one or more of the following characteristics: nutrient efficiency, tolerance to abiotic stress, and/or quality.

Biostimulant products can contain individual product types or mixtures of product types, and these can be both microbial and/or non-microbial. Examples of microbial biostimulants include plant growth promoting bacteria and rhizobacteria (PGPB), non-pathogenic fungi, arbuscular mycorrhizal fungi (AMF). Non-microbial biostimulants can include seaweed extracts, humic substances and fulvic acids protein hydrolysates, amino acids and synthetic biostimulants (AHDB Research Review No. 89). But this list is not exhaustive, there are a lot of different products out there.  

The biostimulant market is growing rapidly however more independent research is needed to test product efficacy, with variable results often seen depending on the conditions or products and crops under test. In the UK, more in field experimentation is needed to find the most appropriate dosage, timings and management for UK crops. Biostimulant product claims include improving stress tolerance and nutrient uptake, but the economics and in field relevance is yet to be proven under UK conditions.   

ADAS has recently been funded by DEFRA to review biostimulants efficacy as part of Project 31280 and these results will be shared when available.   

What is your experience with biostimulants? Have you tested them? Do you have data to share? Please add comments below to start the discussion.  


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Microbial 'Biologicals' can include:

  1. Nitrogen Fixing Bacteria
  2. Phosphorus solubilising bacteria
  3. Mycorrhizal fungi

Other biological substances include

  • Enzymes / phosphatases that make nutrients more available
  • Humic & Fulvic acids - make nutrients more available by chelating cations, supply micronutrients and stimulate root zones
  • Marine or protein extracts
  • Sugars - provide energy source for microbes, or signalling impact in plants for growth promotion or stress reduction.

Good discussion in this LinkedIn post:



Connected Content

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This chapter covers the definition of biostimulants, brief summary of various categories, and how they are used for promoting plant growth, building soil structure, imparting stress tolerance, and contribute to pest and disease suppression. Strategies for using biostimulants as a part of IPM and some challenges and future opportunities were also discussed.

Article by Connor Sible and Fred Below from University of Illinois - view on the website

Our expertise in plant nutrition enables us to meet customer needs in crop health, efficiency and cost-effectiveness. Having been established for over 25 years, our bespoke range of products includes seed treatments, nutritional supplements, biostimulants and phosphites, which can be tailored to customer specifications. 

Uptake of plant biostimulants is predicted to increase because of high fertiliser prices, increased demand for sustainably produced products and the UK Governments climate and environmental goals.   The aim of the Defra biostimulants project, which started in Autumn 2023, is to determine the most appropriate methods to enable the effective and safe use of biostimulants products in the UK, to maximise productivity and explore the environmental impacts of their use.  

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Crop physiology is the study of how plants function and respond to their environment. It involves understanding the factors that affect crop growth and development, such as light, temperature, water, and nutrients, and the physiological mechanisms that plants use to adapt to their environment, such as photosynthesis, respiration, and transpiration. 

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Review by ADAS (Kate Storer) for AHDB in 2016 into the value of biostimulants.

Biostimulants for Global Food Security

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As part of the AICC Crop Nutrition Club 2022, this on-farm winter wheat trial tested the effects of applying Utrisha N at two contrasting N rates. The trial was facilitated by a local AICC advisor, with support and Agronomics yield map analysis from ADAS.

As part of the AICC Crop Nutrition Club 2022, this on-farm winter oats trial tested the effects of applying Utrisha N. The trial was facilitated by a local AICC advisor, with support and Agronomics yield map analysis from ADAS.

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Agro Mavens helps you and your business get talked about in the world of agriculture and agritech. A specialist marketing and communications agency for agriculture, from our base in the UK we work with agriculturally active brands all around the world, from multinationals to start-ups.

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Join us for the third (and final) Cheltenham Monitor Farm meeting of Winter 2023/24. 

This chapter covers the definition of biostimulants, brief summary of various categories, and how

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