Beneficial Microbes


Inoculation is an age-old crop efficiency technique. In former times, farmers dug out soil where crops performed well and put it into poorly performing fields. What they didn’t know was that it was all for a bacterium. Today, the seed industry harnesses biological solutions on a large scale.

Invisible, natural, environmentally sound, and invented by Mother Nature herself, the process of inoculation gives crops a good start. The mode of action is a mutually beneficial symbiosis between the root of a leguminous plant and a rhizobia bacterium. The bacterium attaches itself to the root of a germinating soybean plant in response to certain stimulants released from the root. The root responds by forming nodules through which the bacteria enter via deformations in the root hair or small cracks between cells in the root. The plant reacts by forming nodules – small bullet-like knots on the root’s surface.

A symbiotic relationship

During this relationship, the plant provides the rhizobia with carbohydrates and other nutrients while the bacterium provides the plant with nitrogen fixed from the air to enhance vegetative growth and provide a nutrient essential for photosynthesis. In return, the plant protects the bacterium and provides it with water and nutrients. The symbiotic effect is that the bacterium is protected and fed by the plant while the plant receives nitrogen directly through its root system. Inoculation is a low-cost means of enabling crop efficiency as farmers do not need to add any, or as much, nitrogen. Reducing fertilizer applications is good for the farmers’ wallet and, in this case, the crop as well.

Bayer works on extending the lifetime of the inoculant on the seed. “Our target is at least 90 days,” says Casper van Rooijen.

Bayer works on extending the lifetime of the inoculant on the seed. “Our target is at least 90 days,” says Casper van Rooijen.

The challenges of inoculation

Farmers have known for years that rhizobia are present in almost all soils, but not always in a quantity adequate to establish a sufficient liaison with the legume plant. This is why they transferred soil from one field to another. “Inoculation in the sense of adding bacteria to the seed just before sowing became a common practice more than half a century ago,” says Casper van Rooijen, Segment Manager Bayer SeedGrowth.

In Latin America, inoculating the seed directly before sowing is a common practice among soybean growers. The idea of combining a beneficial living organism with a plant sounds amazingly simple. But it is actually rather tricky to apply the inoculant to the seed in an industrial process: “The challenge is to make it work. What you add to the seed is a living organism that needs to survive as long as possible until it enters its natural habitat, which is the soil.”

Lab testing method for nodulation in one of the Biagro glasshouses

Lab testing method for nodulation in one of the Biagro glasshouses

Finding the real champions

For this reason, Bayer is working on technologies to extend the lifetime of the inoculant on the seed. “Our target is at least 90 days, which is a very long time for a living organism to survive on a dry seed surface,” Casper van Rooijen says. Furthermore, Bayer is working on improving bacteria strains to identify the ones that are the real champions. “It is like sorting out the runners that can go for a marathon.”

But what advantages does buying ready-to-sow seed have for soybean growers over relying on their own skills? “Because it’s all about time and money,” Casper van Rooijen explains. The biggest soybean markets are Argentina, Brazil, and the U.S., where farms sometimes encompass hundreds or in Brazil even thousands of hectares. “At the moment, when the weather conditions allow a grower to start planting, its number one priority is to get the seed into the ground as soon as possible.” Moreover, if the farmer inoculates the seed on the farm, they need to have the appropriate equipment to mix the right dose of bacteria and apply it to the seeds.

The bacterium enters the root of a young soybean plant. The root responds by forming nodules.

The bacterium enters the root of a young soybean plant. The root responds by forming nodules.

All about biologics

Inoculation with rhizobia works with all kinds of leguminous plants, such as peanuts, peas, beans, soybeans, chickpeas, and lentils. For non-leguminous crops, such as corn, soybean, or cotton, Bayer offers other biological solutions, e.g. VOTiVO®, which is sold in combination with the chemical insecticide Poncho® as Poncho / VOTiVO. “It protects the plant from nematode damage and induces responses in root development, which enhances nutrient uptake in the plant and increases yield,” Casper van Rooijen says.

Biologicals have mixed modes of action. They may combine crop protection and crop efficiency. First, many act as a crop protectant agent since they suppress pests or diseases. Second, they stimulate the plant to grow healthier, tolerate stress, and ultimately deliver higher yields. “Combined with chemical crop protection agents, biologicals can contribute to fighting resistance and enhanced performance,” Casper van Rooijen says.

Growth prospects

According to the International Biocontrol Manufacturers’ Association, the global market for biological products is booming with a growth rate of 10 % per year, and thus growing faster than traditional and seed-applied crop protection. For Martin Gruss, Global Head Bayer SeedGrowth, the next level of yield enhancement will be products that display a crop efficiency effect. “This is why we acquired AgraQuest in California in 2012 as the ideal match / perfect complement to our crop protection portfolio.” Two years later, Bayer purchased Biagro, an Argentinian specialist in inoculants.

Established in 1984, Biagro is a well-respected company with 127 employees and a production site at its headquarters in Las Heras, Argentina, as well as in Brazil. Biagro specializes in the production and marketing of highly effective inoculants and biological seed treatments. “Bringing the expertise together, we are able to develop new and more efficient inoculants for legume crops and biologicals for other important crops,” Martin Gruss says. As a result, Bayer has made crop efficiency part of its overall package. “As these biological agents are generally compatible with the chemical products we supply, we are able to bring additional benefits to our customers.”


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