Diatoms in Ag? Tiny Algae with Mighty Impact
What exactly is a diatom?
You have heard us talk about the diatoms in Fish Brew soil amendments like Bold FLO and Rise & Thrive, but what are they? Well, the simple explanation is that they are single celled algae that live in the water. But that would be selling them short.
Diatoms are a ubiquitous group of algae that encompasses approximately 16,000 different species. While associated with marine and freshwater habitats, diatoms are found in sediments, in soils, suspended in the atmosphere and attached to surfaces all around the Earth. These organisms are photosynthetic producers that are the base of many food chains including the extremely important marine food web that supports our global seafood supply. These little microbes are responsible for a huge proportion of CO2 cycling and atmospheric oxygen production worldwide. Fossilized diatoms even play an important role in an extremely interesting global supply chain that takes place naturally between the Sahara Desert and the Amazon Rainforest. The success of this group of microbes is due to their diversity, adaptability, and their ability to grow their own set of armor called a frustule (more about that later!). We could dive into pages of information about the life history of these fascinating organisms, but we are going to focus on what they do in soils. If you want to take a deep dive on general diatom biology, I recommend checking this page out!
So how do they help the soil?
We will focus on the three biggest impacts diatoms can have on your soil; primary production for the soil food web, improving soil structure, and lastly by being a bioavailable silica sink.
Primary production:
These little buggers are the soil food-web shortcut that you did not know you needed! Being a photosynthetic primary producer, they are fully autotrophic (meaning they make their own food) and therefore they make food for the other organisms in the food web. Using CO2 and light they are capable of synthesizing a wide range of sugars and fats to be either stored or exuded into the environment. Stored resources are accessed by the soil food web when a diatom dies or is fed upon by another organism. They also release stored resources into the environment as sugars and polysaccharides. Just like plant roots, diatoms (in water and on land), develop relationships with bacteria to get the resources they need. There is even evidence that certain diatoms will use complex carbohydrates as a gatekeeper mechanism. Diatoms can make sure they only promote the bacteria they want around them by exuding specific compounds that require bacteria to be able to produce specialized enzymes to use those compounds as food. These bacteria supply nutrients and minerals in forms needed by the diatom in exchange for the carbon in the sugars. This also gets the ball rolling on a healthy soil-food web.
Soil Structure:
There are two major ways that diatoms can impact soil structure.
First, the silica-based shell, or frustule, is a rigid structure that helps by providing micro-habitats for holding onto microbes, water, air pockets, and nutrients. These structures greatly improve a soils ability to absorb and retain water and fertilizers even when the diatom is not living and the frustule may be just an empty shell.
Secondly, diatoms can produce exudate biofilms that work like a glue to help bind and aggregate soil particles which further helps retain moisture and organic matter in the soil.
Both of these benefits to soil structure will lead to a soil that can help crops be more efficient with resources like water, organic matter, and fertilizers.
Silicon Cycling:
One of the most significant contributions to the soil system that diatoms make is the role they play in silica cycling; however, this is also an area with significant knowledge gaps. Diatoms process dissolved silica (that is not biologically available to all plants) into a biogenic silica to form their frustules. Some other organisms including some fungi and plants, have this ability to build and accumulate biogenic silica in tissues as well, but others rely on the weathering of biogenic silica sinks in the soil to supply this necessary element. A cycling biomass of diatoms in the soil can act as that as a reservoir of this needed element in your soil.
Plants with the opportunity to incorporate more silicon develop greater structural rigidity, reduced lodging susceptibility, and improves resistance to biotic and abiotic stresses. Anecdotally we have seen this in the form of massive stem diameter in both cannabis and tomato crops grown with Fish Brew Bold FLO.
There is even research that indicates that the level of biogenic silica can influence the bioavailability of potassium stores in soils by influencing the complex soil particle ion interactions. The results suggest that addition of biogenic silica, like that found in diatom shells, free up previously soil-bound and unaccounted for potassium.
Wrapping up: The Diatom Advantage
Diatoms may be microscopic but their impact on soil health is anything but small. These remarkable organisms can deliver multiple benefits simultaneously by jumpstarting the soil food web as a primary producer, cycling silica, and improving soil structure.
Incorporating diatom-rich amendments into your soil strategy is about building a more functional, self-sustaining soil system that can lower fertilizer costs and decrease uncertainty.