POV view of farmer owner control soil quality before seed plant. Future agriculture concept. Close-up hands with the ground. Smart farming, using modern technologies in agriculture

By Harry Brook

"Soil health" is a phrase bandied about a lot. It’s not a new idea but a recycled old one brought about by the realization we rely totally on our soils for food. Soil degradation, through farming and grazing, has caused soil quality declines. Worldwide, soil degradation is estimated to have reduced soil quality and productivity in a majority of soils. Soil is a complex ecosystem and its “health” is difficult to define and quantify. It is also wrapped up with soil microbiology. Most soil health tests measure the biological activity in a soil sample when water is added to a sample, kept at a certain temperature. The amount of carbon dioxide released relates to soil health theoretically, but is this true?

You could also think of soil health as a moving target – the microbes and fungi growing in a soil that is not a static material. Plant-soil-microbe interactions continue to occur as the crop grows and matures. It gets really complicated when you throw in weather variation. The greater the crop diversity, the greater the microbial diversity. Keep in mind that moisture is the main factor controlling microbial activity. Texture, organic matter and pH all affect both plant growth and what populations of microbes are present. There are a limited number of additives that are proven to be valuable to growing crops. They are rhizobium bacteria to capture nitrogen for legumes, and AM fungi.

At the root level, certain fungi and bacteria work with the plant to improve nutrient uptake, ward off infection and improve plant vigour. Arbuscular mycorrhizal fungi (AM fungi) are a group of fungi that form a mutually beneficial relationship with most plants. AM fungi search out suitable plant roots from the exudates released by growing roots. These fungi are not specific to one plant species but some plants cannot be colonized. Canola and mustards do not have AM fungi. The fungi colonize the plant rootlets, feeding off the energy from the plant. In return, they improve nutrient removal from the soil, can act as an extended root system, and can help ward off some plant diseases and provide the plant with greater stress and disease resistance. The hyphae of the fungi are also small enough to access water unavailable to plant root hairs.

AM fungi have been researched and are proven to be of value to growing crops. However, a lot of new, biological products have not gone through extensive testing to ensure they actually work. Does it make sense that using small amounts of biological additives will provide large benefits? Remember, the soil contains thousands of different microbes, protozoans and fungi that are all competing for the essentials of life. How well will the one biological additive used do against such competition? It pays to be skeptical about overblown claims.

One technique frequently used to sell products with no or little proven value is the use of testimonials. I personally see these as a warning sign that there is no proof of value. You don’t rely on testing, just a personal statement. There is no background information on what else they may have changed, other than to use the “wonder” product.

If you are interested in using some of these products, repeatedly try it out and measure results, compared to standard practices. Why waste money on some junk if it doesn’t at least pay for itself and pay you for the effort?

To simplify the issue, organic matter levels in the soil are an indirect measure of soil health. That is an easily measured characteristic of soil linked to soil health. Higher levels are often better.

Some of these biological products might actually help soil health. Experiment and measure and repeat to ensure it isn’t another way to sell you snake oil. It is very much a case of buyer beware.

Harry Brook is Flagstaff County's Agricultural Fieldman. He can be reached via email at: This email address is being protected from spambots. You need JavaScript enabled to view it. or by phone at: 780-384-4138.