Iha Education May Webinar - Fafard Media Additives & Alternatives Update Part 1

In a bark-based mix compared to a peat-based mix, the air space increases while the container capacity decreases. This means that there is more room for air in the bark-based mix, allowing for better aeration and drainage. On the other hand, the container capacity decreases, meaning that there is less space for water and nutrients to be retained in the mix. Therefore, the statement "Air space goes up and container capacity goes down in a bark-based mix compared to a peat-based mix" is true.

Nitrogen "tie-up" refers to the process where nitrogen becomes unavailable to plants because it is tied up in organic matter or other compounds in the soil. The statement suggests that rice hull mixes below 30% do not experience this issue. This means that the nitrogen in these mixes is readily available for the rice plants to use, and there is no significant reduction in its availability. Therefore, the statement is true.

Slime mold, which appears as brown or yellow growth on media surfaces, is associated with greenhouse humidity, bark based mixes, and warm temperatures. This means that all of the listed factors contribute to the presence of slime mold.

Fafard's facilities screen southern pine bark to fine and coarse sizes. The bark screen sizes in inches for fine and coarse are 3/8" and 5/8" respectively.

The biological activity to suppress root rot pathogens like Pythium is highest in the top of the bog. This is because the top layer of the bog is exposed to sunlight and air, which creates a more favorable environment for beneficial microorganisms that can inhibit the growth of root rot pathogens. The top layer also receives more organic matter and nutrients, which further supports the growth of these beneficial microorganisms. In contrast, the middle and bottom layers of the bog may have less sunlight, oxygen, and organic matter, leading to lower biological activity and less suppression of root rot pathogens.

A mix with 30% rice hulls would be best for perennials. Rice hulls are a lightweight and porous material that promotes good drainage and aeration in the soil. Perennials typically have deep root systems and benefit from a well-drained growing medium. The rice hulls can help prevent waterlogging and provide a suitable environment for the roots to grow and thrive.

Silicon has been found to be in higher concentrations when comparing perlite-based mixes versus rice hull-based mixes.

The statement is false because Western peat typically has a higher pH than New Brunswick peat. Peat is formed by the decomposition of organic matter in wetlands, and the pH of peat can vary depending on the type of vegetation, water source, and other factors. Western peat is often derived from vegetation with a higher pH, such as sedges and grasses, while New Brunswick peat is derived from vegetation with a lower pH, such as sphagnum moss. Therefore, Western peat tends to have a higher pH than New Brunswick peat.

Container capacity refers to the volume of water that is retained in the soil after it has been saturated but before any evaporation occurs. It represents the maximum amount of water that the soil can hold and is an important parameter for understanding the water-holding capacity of the soil.