Testing Our Soil For A Nutrient Dense Garden
This year at Verge headquarters (i.e. our home & backyard), our goal is to continue to improve the topsoil and grow nutrient dense food. Since we know that the secret to healthy plants is healthy soil, we have decided to get a comprehensive soil test done this spring.
Prepping the Soil Foodweb test bags and paper work.
Conveniently, there is a local Soil Foodweb lab, only a few hours away in the town of Vulcan, Alberta. With the results, we will better understand our soil, and we can make decisions about amendments, planting, composting, compost tea sprays and what other steps we need to take to achieve our goals. Over the growing season, we’ll report on the test results and what we’re doing with them. At at the end of the season, we’ll retest, and share the results of our actions!
But first, to give you a better picture of the Soil Foodweb, check out this great article by Nancy Lee of Soil Foodweb Canada. And of course, stay tuned for our soil updates… we can’t wait to find out what kinds of microbes and nutrients are lurking in our gardens!
Why should we care about soil food webs?
A healthy, productive soil food web can:
Retain and cycle nutrients
Build and strengthen soil structure
Improve water infiltration and storage
What’s going on in my soil?
Life in the soil is about the search for carbon and nitrogen. Primary producers – plants – are the initial suppliers of almost all the carbon and nitrogen that the soil food web uses. While some soil-living micro-organisms use carbon dioxide (CO2)as a carbon source and/or nitrogen (N2) as a nitrogen source for protein synthesis, organic carbon (C) and nitrogen (N) users dominate in numbers and diversity.
In a teaspoon of productive soil there may be as much as 106 bacteria, with hundreds of different species producing many hundreds of different enzymes, capable of decomposing almost anything that occurs naturally in the soil environment (and even the odd substance which is not naturally occurring).
More about microbes
Bacteria and fungi use the compounds made by plants to grow and multiply, and some compounds are required in higher amounts than others. All compounds or ‘plant nutrients’ undergo some form of microbe mediated decomposition. Any unused compounds are released into the soil environment to be reused. This whole process is what we know as nutrient cycling and retention. Leachable compounds are held in microbe cells until they perish, at which time they become ‘available’ in the soil. Balanced ratios of fungi and bacteria provide a rapid but steady turnover of plant nutrients, reducing and even eliminating the need for supplementing plant nutrients.
Micro-organisms are leaky – they excrete a range of sticky gooey products that help bind soil particles together to form larger, more stable soil aggregates. Fungal hyphae are good examples of living soil binders. These stable soil aggregates are less susceptible to wind and water erosion. A mix of different sized aggregates aids in water infiltration and movement in the soil profile. When a soil has an active and diverse microbial community, not only does water infiltrate more efficiently, but it is stored in the decomposed organic matter. This matter acts like a sponge, soaking up and holding water rather than letting it drain away to groundwater.
Competition in the soil and among the soil food web for resources reduces the incidence of disease caused by plant pathogens. Most bacteria and fungi that live in the soil are benign, although there are some that can cause disease under narrow environmental conditions. A competitive soil food web provides a check against the rapid growth of these pathogens, which are often not very competitive themselves.
Another lesser known function of the soil food web is the production of plant hormones. Bacteria called PGPR can significantly improve plant growth through hormones, without additives.
Putting your web to the test
The Soil Foodweb Inc. assays yield a qualitative and quantitative analysis of soils to provide a benchmark of where each soil is in terms of a “healthy soil food web’. These assays are a tool in the overall health and wellbeing of soils, and are good indicators for biodiversity. They will measure how the soil community is responding to changes in management at both micro and macro-scales. For information on soil analysis contact Soil Foodweb Canada at firstname.lastname@example.org.