Are biostimulants worth the hype?

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The biostimulant market has exploded in recent years, offering an answer to reduced chemical inputs and big healthy crops, but do they actually do what it says on the tub?

Dr Syed Shah, regional agronomist for NIAB, has made it his mission to get under the skin of these purportedly natural enhancers. Having undertaken a number of research trials for NIAB he has written three papers on the subject and will be sharing his knowledge in the AHDB Theatre at the Cereals Event in Lincolnshire on 30 June.

“Biostimulants tend to work in controlled environments, but does that translate in field conditions?” To answer this question, he carried out trials in winter wheat and spring barley on different soil types from 2018 to 2020, with mixed results – sparking interest in further scientific research.

So what exactly are biostimulants? According to the European Biostimulants Industry Council (EBIC) they are material whose function is to stimulate the plant’s natural processes to benefit nutrient uptake, efficiency, stress tolerance and yield.

They may contain seaweed extracts to promote root growth, humic substances, or chitosan to improve the plant’s defence responses. Anti-transpirants reduce water loss, while amino acids and growth-promoting bacteria stimulate root and leaf biomass. There are also non-pathogenic fungi and mycorrhizal fungi soil improvers. Biostimulants can be applied as seed, soil or foliar treatments, and there is reasonable evidence that they improve plant growth and yield.

The biggest issue is that they are currently unregulated in the UK, so as long as manufacturers don’t claim to have any direct impact on pests or diseases, effects don’t have to be independently trialled, explains Dr Shah. “There are no specific guidelines in the EU or UK and there are significant differences across Europe about how they are authorised.”

However, this is due to change: From July 2022 biostimulants will fall under the same regulatory framework as all other types of fertiliser and manufacturers will need to prove the effects claimed on the label. The supporting data can be based on glasshouse or controlled lab conditions but that data might not be relevant or repeatable in the field conditions.

“Some biostimulants have shown to improve crop colour (dark green), above ground biomass and root growth, but will this translate into yield? Companies may show data that demonstrates an effect which may not be repeatable in independent trials – so ask for independent data.”

This is where NIAB’s trials come in. Dr Shah has conducted trials at East Malling, Hereford and Cirencester. On crops given a robust fungicide programme he found little benefit – but where fungicides were reduced the biostimulants had significant positive effects in reducing disease levels and increased yield. Crops on the drought-prone Cirencester soils responded particularly well: “Biostimulant treatments with lower fungicide inputs had significantly higher green flag leaf area compared with reduced fungicide plots,” he explains.

“In a high disease pressure year, fungicide will perform better, but based on these trials, it can be concluded that biostimulants have a place under low or zero fungicide input systems. Soil bacteria and mychorrhizal fungi have also proven to have a significant effect on yield, but we do need to do further research and trials to identify when and how to use biostimulants for maximum effect.”

Visitors to Cereals will also be able to speak with exhibitors specialising in biostimulants, to find out what’s new to the market. These include UPL’s new biofungicides Iodus and Thiopron, the biostimulant Vitalroot and bio seed treatment Sylas. “Sustainability is clearly on the agenda,” says Vaughn Stansfield, UK manager at UPL. “As an industry, we are looking to move forward in a sustainable manner, but it needs to be done profitably, and these two things aren’t mutually exclusive.”

 

 

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About Author

Editor of Agronomist and Arable Farmer as well as responsibility for the Agronomist and Arable Farmer and Farm Business websites. After 17 years milking cows on the family farm John started writing about agriculture in 1998 and has since written for a variety of publications and has developed a wide circle of contacts within the industry. When not working John is an avid follower of Stoke City.