April 19, 2013

This article draws on a recent article in Fertilizers & Agriculture. Many new products are available and may be promoted as “elicitors, phytostimulants, biostimulants, phytoprotectants, biofertilizers, bioactivators, soil enhancers, …..”. Generally the information on these is vague, their mechanisms are not fully understood, and they have not undergone sufficient independent testing. Unlike fertilizers and pesticides, these products are not regulated; marketing does not require proof of effectiveness or full information on mode of action. We hope that some are of value; we expect most to have a short market life.

A suggested categorization of biostimulants is: “humic substances, complex organic materials, beneficial chemical elements, inorganic materials, seaweeds, chitin and chitosan, antitranspirants, and free amino acids.” Some products may overlap two or more categories. The European Commission is moving toward regulation using the definition: “Plant biostimulant means a material which contains substance(s) and/or microorganisms whose function when applied to plants or the rhizosphere is to stimulate natural processes to benefit nutrient uptake, nutrient use efficiency, tolerance to abiotic stress, and/or crop quality, independently of its nutrient content.”

As with any “buyer beware” products, we encourage field testing biostimulant products before fully integrating these into your input package. Past experience indicates that the product effects on yield are likely to be negligible or small and a good trial design is needed to obtain reliable information. Such a field trial can be easily done in cooperation with UNL Extension. Yields with and without the product applied can be measured using a yield monitor or weigh wagon. Ask the supplying company to cost-share or provide free product for the trial. UNL researchers will be interested to more closely evaluate products that are verified to adequately increase yield or improve input use efficiency.

A group of North Central Region soil scientists maintains a Compendium of Research Reports on Use of Non-Traditional Materials for Crop Production, including biostimulants. It's likely to include information on older products, but not necessarily new products on the market.

Charles Wortmann
Soil Fertility Extension Specialist