Hurdles to overcome to achieve biostimulant-driven, low chemical input crop production

Abstract

Societal Impact Statement: Crop production requires considerable chemical inputs that result in significant greenhouse gas emissions and other environmental costs. Biostimulants are natural agents, such as microorganisms or seaweed, applied to plants and soil to stimulate plant growth and reduce chemical inputs. Biostimulant use is rapidly increasing globally, but hurdles remain, hindering widespread adoption. Here, the status of definition and regulation of biostimulants is discussed, including implications of approaches in different countries. A unified definition, harmonised regulation and guidelines for efficacy testing are urgently required to increase farmer confidence and support a future vision for low-input crop production. Summary: Biologically based solutions offer a possible alternative to the heavy reliance of current arable cereal production on chemical inputs. While chemical inputs ensure productivity, they have numerous environmental and economic costs. Biostimulants could provide the needed inputs while reducing the environmental footprint of crop production. They are broadly defined as biological substances that when applied to plants (via the seed, soil or plant tissue) stimulate plant growth, independent of nutrient content, leading to higher productivity than in the absence of the biological agent. Despite the recent boom in number and value of biostimulant products in the market, definition and regulations are fragmented globally, which has resulted in inconsistent value return to farmers. This opinion piece provides a status update on the latest developments in definitions and regulations of biostimulants for arable agriculture and proposes possible routes for ensuring accurate information is available on efficacy and mode of action on plant performance and quantification of environmental benefits. Combined, this timely synthesis provides a basis and future vision for the adoption of effective biostimulant application for sustainable crop production.