Taking the soil microbiome to lunch

Research is just starting to reveal life below the soil surface

Taking the soil microbiome to lunch

Any farmer who has ever asked questions about whether the wide range of crop biological products are necessary and really work to benefit the soil or serve to improve crop yield and quality need to keep asking questions.

It is not that the marketplace is full of suspect product claims — the biological industry has done a decent job over the years to weed out fraudsters and build a fairly trusted reputation — but exactly how added biological products work within plant and soil microbiomes is still a relatively new research area. (In case you missed that day in science class, a microbiome is the community of microorganisms living together in a particular habitat. Humans, animals, soils and plants all have their own unique microbiomes.)

Ask questions, examine research results and data and conduct trials to evaluate the efficacy of biologicals on your farm.

And farmers have no doubt been to field days, particularly in recent years, where researchers have grabbed a shovel full of dirt just to demonstrate the complex community of life that lives under our feet that includes plant roots, viruses, bacteria, fungi, algae, protozoa, mites, nematodes, worms, ants, maggots and other insects and insect larvae (grubs) and larger animals — all those living creatures are called the soil biota.

So, when the “FIX-All Biological Co.” comes along with a product that is a stubble digester, or helps to revive the soil, or enhances soil biology and root zone environments, or speeds up nutrient cycling, how does the farmer know if it is something they need and if it will work?

Soil scientists, soil microbiologists and biological product developers all point to a similar answer: do some homework to better understand soil microbiology, be rigorous about asking questions, ask to see relevant research and evaluate some field test strips before you treat the whole farm.

Too early for prescriptions

“In terms of how plants interact with soil microbes, it is just so early,” says Mark Belmonte, a professor of biological sciences at the University of Manitoba. “In terms of understanding how an individual microbe or even a stack of microbes in a product will interact with the plant or the soil, we still have so much to learn that it is difficult to assess whether you need one or the other.

“We have the tools to profile all the microbes in the soil to create what’s known as a microbiome of the organisms in the soil. Plants also have a microbiome but there is so much we don’t know about how different plants or different crops will interact with the microbes in the soil. Different crops, different plants will select for or encourage certain microbes to multiply and become active.”

Belmonte says in that complex community of soil microbiology “there are the good guys and the bad guys.” The challenge in cropping practices and use of biologicals is to promote the activity of the good microbiology such as mycorrhizal fungi, which help plants grow and communicate with each other, and discourage or control the bad characters such as Rhizoctonia or Verticillium, two pathogenic fungi that can lead to common crop diseases.

“My message to farmers is to learn as much as they can about the science of soil microbiology, talk to experts and research articles online,” says Belmonte. “And when they are looking at a particular biological product, ask what types of studies have been done, ask about what microbes are involved, what does the product do and how does it perform under different environmental conditions? How is it applied, is it a seed treatment or sidedress? Is it a single microbe product or several stacked together?

“Finding the answer can sometimes be difficult and I don’t believe that the industry or even myself as a researcher have a sufficient level of understanding to write a prescription. How do biologicals work and interact with the crop? It is too early to prescribe the biologicals that are needed to benefit soil health.”

He urges producers to look to companies who have done the research that is relevant to growing conditions in Western Canada, citing Nexus BioAg and Lallemand Plant Care as two examples of companies with research on a range of biological products.

Holistic approach

Over at the University of Alberta in Edmonton, Sheau-Fang Hwang, a plant pathologist and professor at the Faculty of Agricultural, Life and Environmental Sciences, urges students as well as farmers to apply an integrated approach to crop protection that involves a combination of chemical, biological and cultural control measures.

Hwang says there are many good biological control products on the market, but their effectiveness is not always consistent. “Sometimes we can test a biological product in the greenhouse and it looks effective, but when we try it in the field, it might only be effective once in five years. And that has to do with how it performs under different environmental conditions.”

Hwang says research has led to the development or discovery of more effective biological products over the past 15 to 20 years. Bacillus subtilis, for example, is a bacterium that can be effective in controlling crop diseases and as a biological control agent it has a much longer shelf life than some of the earlier microorganisms.

She also notes that the formulation of biological products has improved as well, pointing to products developed with nitrogen-fixing rhizobium bacteria to inoculate pulse crops are now available in peat, liquid and granular formulations.

“Particularly when it comes to crop diseases, I urge farmers to take a holistic approach,” says Hwang. “Follow a more extended crop rotation if possible, to reduce the risk of disease development, grow crop varieties developed with improved disease resistance, use biological products with effectiveness backed by research and, as necessary, also be prepared to apply chemical control measures.”

Farmers from Missouri

And Dan Custis, who has long been involved in the biological products industry, also urges farmers to do their research and ask questions. Custis, based in Ohio, is co-founder and CEO of Advanced Biological Marketing (ABM), which develops and markets a wide range of biological products.

“With biologicals, or any product, farmers need to do their homework and ask to see the research,” says Custis. “Here in the U.S., Missouri is known as the ‘show me state,’ show me the proof. I have been all over the world talking to farmers about biological products and I think they are all from Missouri. Every farmer wants to know what a product can or cannot do and there are no silver bullets.”

Custis, closely involved with biological products developed to work with corn, soybean, pulse and wheat crops, sees biologicals being used as a companion or to complement chemical seed and soil treatments. “We see them as largely being there to enhance crop protection measures and enhance crop performance,” he says.

Biologicals, for example, have potential to develop a healthier plant overall, with a more robust root system that is better able to defend itself against disease and insects and better able to process nutrients, which in turn should increase photosynthesis in the plant. “And, ultimately, that all should translate into increased yield,” he says. “The ultimate goal is to increase the amount of grain the farmer gets to sell.”

Custis says when he was a kid growing up on the farm, a few decades ago, it was more common to have a four-crop rotation that included corn, soybeans and wheat as well as a legume such as alfalfa and clover. In more recent years, farmers have gone to shorter, corn-soybean rotations, for example, or even a monoculture of growing one crop several years in a row. Reduced crop diversity can be hard on the soil, depleting nutrients as well as soil quality factors.

“But farmers today are smart guys, and interested in using the tools available,” says Custis. “That involves providing a balanced fertility program of macro and micronutrients and they are also becoming more interested in overall soil health and improving the performance of soil microbiology.

“When we talk about the benefit of biological products, they are willing to listen,” he says. “But they are all from Missouri, they say ‘show me.’ And we say, ‘If you have never used a biological before, then don’t put it on all your acres, do your own field trials.’ Plant half of a field with a product and the other half without and see what it does. And we also have research from our own replicated field trials over several years we can show them as well.”

Custis, who has been involved with the biological products industry for 25 years, says there are a lot of products in the marketplace, “but I think, really, we are just seeing the tip of the iceberg these days,” he says. “There is just so much more we have to learn about all the interactions in the soil. We have spent decades looking at the plant above the ground, and now we are just starting to look at what’s happening below the ground and what can be done there to optimize crop performance.”

About the author

Field Editor

Lee Hart

Lee Hart is editor of Cattleman’s Corner based in Calgary.

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