Microbial Question Guide

CONSIDERING MICROBIAL PRODUCTS? ASK THESE QUESTIONS

The Iowa Corn Promotion Board (ICPB) invests corn checkoff dollars to develop and defend markets, fund research and provide education about corn production and uses. The ICPB provides information and educational opportunities for farmers to use to make production decisions that work best for their farm, which includes staying knowledgeable of new market opportunities.

The development and marketing of microbial products (also known as biological products) has increased dramatically in recent years and projections predict this growth will accelerate. The ICPB is providing you with this grower guide to help you address questions when deciding if these products are right for your operation.

With hundreds of companies working to develop new microbial products claiming to promote plant growth, bolster yields and/or safeguard plant health, determining what (if any) products are worth trying can be overwhelming. We put together a list of fundamental questions to guide that vetting process and help farmers make informed decisions in a rapidly evolving market filled with opportunities and uncertainties.

THERE ARE MANY PIECES TO THE

WHAT MAKES MICROBIALS DIFFERENT?

How do I know it’s a microbial?

The active ingredients section of the product label should clearly depict the genus and species of the included microorganism. The genus will be capitalized and the species will be lowercase. Some common genus names include Rhizobia, Lactobacillus, Bacillus, Pseudomonas, Trichoderma, Clonostachys and Glomus

What are the properties of a microbial product?

Microorganisms are not traditional active ingredients or fertilizers; they have unique properties that interact with the environment, plants and soils that affect their function and efficacy. Those properties should be clearly stated on the label. The concentration of the microbial active ingredient is typically expressed in colony forming units per milliliter (CFU/mL). CFUs define the number of microorganisms capable of multiplying and forming a colony.

What is the microbial’s mode of action?

Microbials work in distinct ways. Some affect nutrient uptake, while others function as a crop-protection product. Even when microbials impact plants in similar ways, the mode of action involved as well as the response to environmental and management conditions can vary. It’s important to have a basic understanding of how the microbial product works and what influences its efficacy.

What are the storage, handling and application requirements of the microbial product?

Look for independent test results

Local independent tests can be more insightful than field trials conducted by the company selling microbials. If a company is hesitant to provide independent testing results, proceed with caution.

Many microbials must be stored and handled in a certain way to maintain and maximize their effectiveness. Some products are more sensitive than others and may lose their efficacy if protocols regarding factors like temperature, pressure and humidity are not followed. The application requirements should also be clearly stated on the product’s label or spelled out in accompanying technical information. Make sure you understand all storage, handling and application requirements and weigh them against the expected crop benefits of using the microbial product.

What factors influence microbials’ effectiveness?

Weather, soil fertility and microbes in the soil can all influence whether a microbial has a positive effect on the crop. Make sure to discuss with the company marketing the product the many soil and atmospheric variables that can affect product performance. You should also find out whether the product has been tested under conditions similar to those on your farm. Ask other local users about their experiences with the microbial, if possible.

Has testing shown this product works in different soil types an d environments?

Many microbials are sensitive to their environment, with non-ideal conditions reducing their effectiveness. Discuss the characteristics of your soils with the company offering the microbial product to determine whether it’s a good fit. For example, a microbial that increases the availability of nitrogen to the plant may not be beneficial in a field that is already high in available nitrogen.

Does this product deliver a return on investment?

Products intended to increase plant growth or replace traditional fertilizers should be able to do so in a cost-effective way. This might mean boosting yields enough to cover the cost of the product or providing a more affordable option versus the input it’s replacing.

You’ll need to know whether the microbial is a replacement or a supplement to an existing input. If it’s supplemental, make sure your calculations consider any reductions in use of the original input.

Local and independent testing results and testimonials from trusted sources can also help you gauge whether it’s a wise investment.

Colonisation of the target niches in the plant environment

antagonistic or synergistic effects

Long-term establishment of microbial inoculants

Expressing plant growth and health-promoting effects

community composition

oxygen availability

host range

delivery approaches

physiological activity

interaction with native microbiota

suitable formulations

biotic and abiotic conditions

physiological adaptation

root exudates and other metabolites

compatibility with the target plant

TRIALING AND ADOPTING MICROBIALS ON YOUR FARM

Can I test the product on my farm first?

Some companies offer the option of testing the microbial product on a small number of acres before purchasing it in bulk. Take advantage of these opportunities.

Are there effectiveness guarantees?

Program conditions, performance claims and product guarantees vary widely. In some cases, farmers must buy a minimum number of microbial products to qualify for the guarantees. Make sure you have a clear understanding of program details and any guarantees before purchasing the product.

Is agronomic support available?

It’s always helpful to have agronomists and technical support staff available, especially if they have a good understanding of the microbial product and the farm using it. These professionals can be a great resource on everything from best-use suggestions to troubleshooting. Make sure you know whether and how much support is included before investing in a microbial.