Increased focus on the environment, high input prices and the ability to target specific crop needs have all been identified as key market drivers for the biostimulants industry.
With more than 200 European manufacturers, an estimated €1billion worth of total sales of biostimulants was predicted by the European Biostimulants Industry Council (EBIC) in 2019, with a market growth of 10-12 per cent each year.
But, despite their growing popularity, the efficacy of some products is still largely unknown. A review of biostimulants undertaken by ADAS concluded that while some biostimulants are associated with improving plant tolerance or nutrient uptake, there is limited UK data available to support this, particularly field data.
The study, conducted in 2016 on behalf of AHDB, aimed to put some understanding behind the function, efficacy and value of biostimulants in cereals and oilseed rape in the UK, but was expanded to include other plants such as tomatoes and lab and greenhouse studies, because much of the evidence available was not based on field work.
Dr Kate Storer, crop physiologist at ADAS explains: “We looked at a whole host of information, where possible using information on cereals and oilseed rape in the UK, but we really struggled to get evidence.
“We did find that some of these products had an effect, but it was mostly based on greenhouse data and, when they did have a positive effect, it was often from experiments under controlled conditions, not from the field.
“If we take one of the categories with more evidence, we found 16 experiments or sites studying seaweed extracts, of those 50 per cent were pot or hydroponics based, three were from UK field conditions and only one of those showed a positive below ground response. There were no UK based yield studies available.”
The study concluded that more substantial UK evidence needs to be developed for widespread use in arable crops, particularly under field conditions, and there needs to be a clearer understanding and demonstration of the potential economic benefits of these product types.
Biostimulants are often claimed to buffer against a bad year, such as in drought conditions, so if products are cost-effective enough to warrant regular use as an insurance policy, they may become more widespread.
The review indicated potential benefits of complementing or improving the efficiency of fertilisers or plant protection products, to produce aggregated marginal gains that cannot be achieved with conventional crop management.
Dr Storer recommends growers who are considering adopting a biostimulant to undertake field trials on their farm.
She says: “Do not just put it on the whole field, test it on a tramline and see how it compares to your usual practice. Ask questions and request to see trials evidence if you are considering trying it out. A lot of these product types have some evidence of working in the academic literature but, when it came down to translating that into field evidence, that is where the gap was.”
ADAS has produced a guide for farmers which summarises how to set up a good crop trial. It is available free on their website.