Microbian Grower Guide

MICROBIAL PRODUCTS: THE BASICS

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 farms, 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 that this growth will accelerate into the future. The ICPB is providing you with this grower guide to ensure you are aware of the plusses and minuses of these products, and to point out the importance and role of microorganisms in crop production.

More than 400 companies are involved in research, development and marketing of microbial products. In some cases, these microbes are naturally occurring; in others, they are altered to perform a specific function for the crop. The companies marketing them make a wide assortment of claims, but there’s a relative scarcity of local, independent testing results. These products hold a lot of promise, but also some uncertainty.

Farmers interested in microbial product options should educate themselves on their potential value and limitations on their farm. This guide can help.

The above- and below-ground zones in a cornfield are teeming with naturally occurring microorganisms, many of which are beneficial to crops. This community of microorganisms is called a plant microbiome. The assembly of microorganisms that live together in and near a plant interact with each other to carry out biological processes. Each plays an important and connected role in plant growth. Together, they form a microbial ecosystem.

Soil Microorganisms Critical to Plant Growth

Bacteria and fungi are the most important microorganisms when it comes to plant health. They are also the most abundant microorganisms in soils, accounting for over 100 times more biomass than other microbe types. Some common microorganisms significant to global agriculture include:

• Rhizobia (bacteria)

• Mycorrhizae (fungi)

• Bacillus (bacteria)

• Azospirillum (bacteria)

• Pseudomonas (bacteria)

• Trichoderma (fungi)

• Streptomyces (bacteria)

The microbes that live in soil surrounding the root of the plant make soil nutrients more available to plants using biological processes. Some of the benefits to the plant include:

• Promoting plant growth

• Increasing nitrogen fixation and nitrogen availability

• Enhancing phosphate solubilization and availability

• Suppressing pests

• Functioning as plant probiotics

Microbial diversity and activity associated with healthy soils help all the processes work together.

Results Will Vary

Some farmers have reported positive results from microbial products, while others have not seen an advantage with those same products.

Why the disparity? Microbial products do not operate in a vacuum. How and whether they work depends on many factors – some of which farmers control and some of which they can’t. Farmers can control the product type, when, how and at what rates they apply a microbial product to a crop. But they have less to no control on other efficacy-impacting factors, such as:

• Soil characteristics (e.g., temperature, pH, moisture)

• Weather conditions

• Native microbes in the soil

Virtually any factor that alters the biology and chemistry of the plant or root zone can impact the efficacy of a microbial product. It’s also difficult to replicate the complex and interconnected factors of the field in a lab setting. Consequently, a microbial strain may do well under controlled conditions, but its performance in the field may vary widely.

Major Growth Projected for Global Ag Microbial Market

The relative newness of this market makes it difficult to estimate its size. Two companies that have provided estimates predict rapid expansion.

ARE MICROBIAL PRODUCTS RIGHT FOR YOUR FARM?

There’s a lot to consider when it comes to microbial products. Perhaps the most important factor for farmers is the bottom-line economic analysis. Start by answering these questions:

• Is the microbial product a supplement that reduces the amount of the current input being used?

• Does the microbial product replace the current input?

• Is the microbial an additive product with no impact on the application rates of other inputs?

Those answers can help farmers calculate whether their return on investment (ROI) would be positive, neutral or negative. Those calculations should also incorporate any added or reduced fuel, labor or equipment costs. And of course, the microbial product’s potential impact on yield is an important factor to consider along with the input cost variables.

More research is needed to understand the value of the rapidly growing microbial market. In the meantime, farmers should carefully evaluate what research and local independent testing results are available and consult trusted advisors before making decisions for their cropping systems.