Microbials Do They Fit Your Farm?


“It has to fit the way you farm.”

Mark Abildgaard, Western Regional manager for the biological crop input provider Agrinos, was speaking about the benefits of using his company’s bio stimulant products, but also noting that not all growers have management systems where the products will work.

Abildgaard, a workshop presenter at the South Valley Nut and Citrus Conference, explained that plant growth promoting soil microbes capture and digest the soil nutrient reserves from inorganic and organic fertilizers and release them in a plant usable form, particularly phosphorus (P) and potassium (K). Those microbes also capture and fix nitrogen gas for use by plants, create soil organic matter that improves soil water management and increases available nutrients in the soil.

In the past decade there has been a surge in the development of microbial products for use on a wide range of crops. The products are marketed under a number of names including bio stimulants, bio fungicides, and bio-fertilizers. They may contain one strain of bacteria or fungi, or many. Some products are soil applied and others are foliar.

Recognizing that microorganisms (usually bacteria and fungi) could benefit agriculture is not new. Beneficial bacteria that form nodules in the roots of legumes and provide the plant with nitrogen captured from the atmosphere—have long been known to boost legume yield and health. Mycorrhizal fungi have been recognized as important plant partners, scavenging nutrients from the soil and delivering them to plant roots.

According to the United States Department of Agriculture’s (USDA) Natural Resources Conservation Service (NRCS), there is an incredible diversity of organisms in soil. These microbes range in size from the tiniest one celled bacteria, algae, fungi and protozoa to larger, more complex—and visible—earthworms, insects and small invertebrates.

Microbes live in the microscale environments within and between soil particles. Differences over short distances in pH, moisture, pore size and the types of food available create a broad range of habitat—or and absence of habitat. By eating, growing and moving through the soil the plant growth promoting microbes contribute to healthy soils and plants.

New Technology
New technology now allows for the exploration of diverse microorganisms and the beneficial functions they can provide. Passage of the 2018 Farm Bill was an important milestone for the growth and adoption of biostimulant products as the bill included statutory language about the products. That set the stage for a formal regulatory framework to ensure the appropriate process for review, approval and uniform national labeling of agricultural biostimulant products. The bill was also the first federal recognition of biostimulant products as an emerging technology for production agriculture. The Farm Bill describes a plant biostimulant as a substance or microorganism that, when applied to seeds, plants or the rhizosphere, stimulates natural processes to enhance or benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress or crop quality and yield.

The USDA is required to perform studies on the potential regulatory and legislative reforms necessary to ensure appropriate review and labeling of microbial products.

Most companies that generate microbial products follow a similar process. First, many microorganisms are captured from soil or plant samples, and are then grown in lab cultures. Next, these lab-grown microorganisms are tested for their ability to improve the growth of crop seedlings in a lab or greenhouse. Promising microorganisms then advance to field trials. If successful in the field, a microorganism will likely be slated for commercial approval and production. Large quantities of the microorganism must then be grown, formulated, and packaged for sale. Trials have also shown that the microbial products help prevent plant stress and improve plant performance.

Agrinos microbial products, Abildgaard explained, deliver a diverse microbial consortium with a broad range of benefits, often with redundancy across strains. That supports consistent results across a diverse range of environmental conditions and crops, he said.

“You need a diverse package to ensure performance,” Abildgaard said.

The major bacterial genera represented in the consortium are azotobacter vinelandii and clostridium pasteurianum.

Agrinos’ proprietary products were developed through the High Yield Technology platform.

Field Trials
Field trials conducted between 2010 and 2018 are showing that the microbial products are improving yields. Third party researchers conducted replicated trials with the Agrinos products applied via drip irrigation or as a foliar spray.

In almonds, 15 trials were completed over two years. Average yield increase with Agrinos products applied in the orchard was 17 percent. In addition to almonds, the products were used on crops including grapes, melons, tomatoes and wheat. Field trials evaluated Agrinos products used along or in combination with each other against untreated grower standard control plots and competitive biological products.

Trials conducted by Sawtooth Ag Research over the last two growing seasons found improved yields. In 2018, a trial in a 12-year-old Terra Bella area Nonpareil orchard found a four percent increase in yield in treated trees compared to a grower standard program. The Agrinos product iNvigorate was applied via drip at two quarts per acre at petal fall in that trial.

Another Terra Bella trial in seven year Nonpareils saw a 17 percent increase in nut meat yield over the grower control. In that trial, the Agrinos product BSure was applied at one quart per acre in a folia spray at bloom and petal fall.

Mike Austin of Agrinos said the company has put a premium on constantly measuring and validating the agronomic benefits of its products with research and field trials. It is gratifying, he added, that the results are verified repeatedly over long periods of time and with different environments and production systems.