A Systematic Approach to Field Testing of Biological Products for Horticulture Is Required to Improve Food Security

ABSTRACT Food security challenges require immediate action to increase food production. Many biological products derived from plant, animal or microbial sources claim they sustainably increase yield, but there are concerns about biosecurity to be investigated before their introduction to the field. As with chemical inputs, biological products should not impact microbial communities integral to crop growth and ecosystem function. This review assessed horticultural field trials of soil amendments, biofertilisers, biostimulants, microbial inoculants, and combinations of these, collating evidence of changes to the host microbiome and performance, to identify knowledge gaps and suggest recommendations to accelerate research in this critical area. There was wide variation in the depth and type of data collected. Crop performance was commonly measured using biomass or yield, and metabarcoding assessed microbiome diversity, composition and abundance. Most trials focused on annual crops, measured the soil or rhizosphere microbiome, generally only assessed bacterial communities, that were often measured once. There were few long‐term trials, even for perennial crops. Trial designs require a systematic approach with measurements through the growing season across different climatic regions and soil types and analyses of correlations between the product, crop yield, and the microbiome to increase knowledge of product effectiveness. Growers need evidence that products maintain or increase growth or yield, without negatively impacting the microbiome or ecosystem functions, while reducing synthetic inputs. Testing of microbial products should confirm they do not cause harm to crops or the environment. Integrating crop measurements with microbiome data and providing open access to microbiome (sequence) data, will assist identification of products which can increase food system resilience.