By Dale Overton, B.Sc.

There are many other important factors which influence the effectiveness of any biological inoculants in any given situation. For example, prevailing weather conditions can affect what microbes are currently active in the soil. Consistent cool, damp weather will almost certainly cause outbreaks of fusarium sp. on Poa greens, in which case, little can be done to control an outbreak. Healthy plants will be able to withstand the colonization of such pathogens.

When using or incorporating an ECT it is vital to consider and understand ecological principals as soil is a complex living system containing an unknown number of organisms, which live and work together. In many natural systems, pathogens are rarely observed. When observing a healthy ecosystem, one will notice there are very few diseased organisms. This is because the system is balanced (or stable). Natural checks and balances exist in such systems, so disease is minimized. When a system is unbalanced or stressed, there is a decrease in the ability of the system to withstand disease pressure or other environmental stressors.

Golf courses are perfect examples of a stressed system. There are few examples of plants that are exposed to more stress than golf greens. They are cut almost to the root/shoot interface daily, compacted from steady play, exposed to an array of chemical inputs, and built on poor soil (i.e. sand/peat). Pathogen pressure can be very high in such situations because the natural ecological balance is off. Proper incorporation of a high-quality ECT will help to alleviate such pressure by increasing plant health and various indirect mechanisms.

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By Dale Overton, B.Sc.

Providing the ECT is made properly (using a bioreactor or aerated brewing unit) superintendents should see a significant increase in primary and secondary roots after a few applications. After five or six applications, tertiary and quaternary begin to proliferate extensively in various varieties of creeping bentgrass, annual bluegrass, and many other turfgrass varieties.

A qualitative measure has also been noticed in the increase of plant vigour (i.e. colour and growth rate). This can be quantified by measuring chlorophyll concentrations and/or brix levels within the leaves.

Further, as a result of increased root biomass and microbial activity, the ability for turf to recover from the stress of play and compaction is increased greatly. With increased root function, in addition to biomass, plants can access water locked up in soil colloids and stretch further into the soil in search of water.

Some superintendents have also noticed a decrease in disease pressure, although it is difficult to prove ECTs prevent disease. The mode of action is poorly understood; however, the bottom line is healthier plants have enhanced ability to withstand stress, whether pathogen or condition related. Finally, although ECTs are not a replacement for fungicides, they may help reduce the amount required for prevention as it creates healthy plants.

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Building controlled microbial compost. Photo courtesy Overton Environmental Enterprises

By Dale Overton, B.Sc.

Most ECT recipes usually comprise the following:
• Plant-based thermal compost: Engineering begins with the compost building process (as mentioned earlier, not all compost is created equal as a variety of recipes can be used). Parent material, amendments, temperature and moisture control, and maturity are all factors that influence how effective the compost will be. Mature compost contains a large diversity and a number of soil microbes and micro-invertebrates (i.e. protozoa, nematodes, and insects), which all have important roles in the soil.
• Worm castings: Similar to compost, not all worm castings are the same. High-quality worm castings are built using standard operating procedures to ensure consistent results. Worm castings may contain a vast array and number of PGPR and other beneficial microbes. High-quality ECT will almost always include worm castings as part of the blend.
• Microbial foods: These comprise a number of products used to feed various types of microbes during the brewing or extraction process. Some of the products used in microbial foods include humic/fulvic acid, powdered molasses, grain meals, kelp products, fish fertilizers, and other plant-based extracts. Quality microbial foods will contain a balance of these ingredients.
• Catalysts: These are an array of readily available food sources for microbes, which are built of simple and complex carbohydrates, along with humic and amino acids. These products help spike activity in the ECT prior to application.

Read the full article: Shedding Light On Engineered Compost Teas