When Biology Meets Chemistry

Tuesday, April 23, 2024

Biological amendments might be just what your soil needs.

By Stacy Berry

Biological amendments – or simply biologicals – are relatively new to the conventional row crop world and can be a great way for Ontario growers to better utilize nutrition already present in their environment.

However, most people who have been farming for a while "probably didn't learn about biologicals in university or college, so the familiarity isn't there to make (biologicals) top of mind in your regular crop plans," says Brady Code, the Biologicals technical lead with Syngenta Canada.

Gustavo Roelants, marketing lead for Biologicals with Syngenta Canda, explains, "biological products are derived from natural elements or inspired by natural processes to protect and promote plant growth. There are three main categories of biologicals: Biofertility, biocontrol, and biostimulants."

For this article, biofertility and biostimulants are the focus. "Biocontrol products are crafted from naturally occurring elements to help manage (pests)," says Roelants. They are used in conjunction with pesticides rather than soil nutrition.

The main difference between biofertility and biostimulants is how they work. "Biofertility products address nutrient needs," explains Roelants, while biostimulant products "stimulate a plant's natural processes."

"Biofertility products colonize the rhizosphere and/or the plant itself and encourage growth by synthesizing growth-promoting compounds. Examples include beneficial microorganisms that can fix nitrogen from the air or solubilize phosphorus from the soil," Roelants continues.

Basically, "you can get nitrogen (and other nutrients) through fertilizers, or you can get them through bacteria," says Manas Banerjee, the CEO of XiteBio Technologies in Winnipeg, Man. "The bacteria – the most common being Rhizobium – give nitrogen back to the crops through nodulation. They are able to pull nitrogen right from the air. It's a symbiotic relationship between the bacteria and the plant." The term for this process is nitrogen fixation, where the bacteria give the plant usable nitrogen in exchange for 'room and board' in the nodules formed on the plant roots.

If you grow pulses, you've already heard of nodulation and nitrogen fixation. However, other crops like cereals and oilseeds don't have this inherent nitrogen-fixing ability. In fact, these crops can have distinct microbiomes, which can impact the yields of the following crops planted in the field the next season.

"Plants are fussy about nutrient forms. They will only take up nitrogen in nitrate or ammonium forms. They will only take up sulphur in sulphate forms," says Banerjee. When a farmer adds phosphate to the soil, a rough estimate is "40 per cent (of the nutrients) are available, and the other 60 per cent is unavailable." The specific ratios vary with different nutrients.

When nutrient availability is considered, there are two parts to the explanation. One is the form, as has been mentioned, but the other is within the soil. Plant-available forms of nutrients are the ionic forms – like nitrate and sulphate. These ions have positive or negative charges. Positively charged ions, like ammonium (NH4+), will be drawn to the negatively-charged organic matter and soil particles. This "fixes" the nutrients to the soil, removing them from the soil solution and making them unavailable to the plant for uptake. Alternatively, other ions in the soil can have chemical reactions with the nutrient ions we need, and can precipitate out the nutrients, also making the nutrients unavailable to the plant.

Fortunately, the bacteria present in the biological amendments "can unlock those bonds, so the plants can take them back," says Banerjee.

This is where biostimulants come into play. "Biostimulants contribute to overall plant health, improving nutrient use efficiency, crop quality, or the plant's ability to cope with stress," explains Roelants.

Healthy soils have a variety of microbes, and the bacteria in biologicals is naturally derived. Agriculture is an essential industry; unfortunately, agricultural practices also interrupt many of the natural cycles that would occur without human influence. This can throw the biology of the soil and the system out of balance.

"Chemistry can't sell without the biology," says Banerjee. "I would argue that biologicals might be farmer's least expensive (soil nutrition) option. This is nature enhancing nature."

Banerjee is hopeful for the biologicals market within Canada. "There's already a huge global market; I'm confident that Canada's market will grow, too." However, a big problem for the biologicals industry is "farmers going back to what they know will work, because the other answers aren't there." Banerjee is confident that those answers will come.

"Our biology is getting nearly as precise as the chemistry."

Unfortunately, the history of biological amendments is a little bumpy.

Chris Dumigan, the Biologicals field specialist with Syngenta, explains, "there is widespread skepticism surrounding biologicals in Canada. Much of this likely comes from a number of products with grand claims, poor supporting evidence, and lack of knowledge around the product fit to deliver.

"It is important to understand that most biologicals are not a one-size-fits-all silver bullet, but rather, technology that has the potential to deliver great results in the field if it is used right. This is why companies have invested into R&D about how to use their products with precise application information."

Banerjee concurs. "Don't promise a magic wand or a 100 per cent success rate. Biologicals won't solve everything, and Mother Nature can be treacherous. However, when our customers use our biologicals, they like it and they can trust it."

Companies are investing the resources to make products better, explains Code. "Syngenta is building out the agronomic understanding with the Canadian-led performance data growers expect from a company like ours. We can then offer a support team to provide agronomic recommendations and advice tailored to your operation."

The questions and uncertainty around biologicals are a little like the question of the chicken and the egg. "The more that farmers use biologicals," says Banerjee, "the more companies will be interested in them. Then more smart people will study them, and the quality and consistency of the product will increase."

Code: "With things moving so fast in this space, we're always trying to improve on the consistency of results with biologicals. We appreciate that growers play a large part in our ability to fine-tune best practices."

"Technology is now at a stage where we can begin to understand how biological products work, Code continues. "An example is Megafol … a solution containing (the same) compounds seaweed plants make to be able to survive in their harsh environment. We can test these compounds and see what plant genes are turned on or amplified. Then test (those compounds) on (crop) plants and see what effects they have, like improving recovery from drought, heat, cold or even hail.

"There's more science and understanding behind biologicals than ever before."

Companies selling biologicals also know that user-friendliness is crucial. "People won't use a good product just because it's good," explains Banerjee. "They'll use it because it's easy to use. No one is going to keep something frozen. No one wants to use crazy amounts of water or to buy a specialty piece of equipment just for one product. The product must fit into the farmer's management system and into their budget."

Code agrees. "Because we know that growers aren't looking to do another pass with just their biological in the tank, we are testing our biological portfolio the way you as a customer would use it – in the tank with a planned (crop input) application." Farmers are often the best field-level testers when it comes to product development.

"Growers are often curious and ingenious experimenters on their farms," says Code.

Biological products generally come with a broad range of rates, and growers are relatively safe to experiment with applications, with no risk of resistance issues when they drop the rates.

Banerjee has an ambitious goal. "I think every farmer should be using at least one biological. It would, of course, be nice if they used ours, but I hope they try any of the good products out there." He hopes that farmers will "accept the technology – the more that farmers use it, the more the demand for quality and consistency will grow, and industry will respond.

"More growers are thinking about climate change and the environment, and they are looking to reduce applications. Biological products can do that, while simultaneously getting better returns to the farmer." BF