Compost and its liquid derivatives offer a powerful arsenal of tools for organic and regenerative agriculture. While Wikipedia defines compost as ‘decomposed organic matter’, this blog post explores the distinctions between biological compost, compost extract, and compost tea. We delve into the unique characteristics, benefits, and applications of each of these amendments, providing a comprehensive understanding of how they can maximize soil health and nurture thriving plants.
The word compost can conjure images of stinky, rancid, rat magnets, with liquid slime oozing from the bottom. Biological compost breaks all these rules. It smells like a sweet forest floor, attracts only earthworms, birds, and curious farmers, and should only yield a couple of drops of liquid when squeezed tightly in a fist. Biological compost is produced using an aerobic decomposition process involving a diverse mix of organic materials, typically 15-20% high nitrogen, 30-35% green, and 50-55% woody. Moisture levels are maintained at around 50-55% throughout the composting process, which takes approximately two weeks, after which time the material is matured for between 6 months and 2 years to reach optimal biological community composition. Biological compost is meticulously maintained in aerobic conditions at temperatures high enough and long enough to ensure decomposition occurs throughout the entire pile, eliminating weed seeds and human pathogens. Biological compost stands apart from the traditional definition of compost in its high diversity of locally adapted soil organisms that perform crucial functions within the soil food web. This vibrant ecosystem of microorganisms, including bacteria, fungi, nematodes and protozoa contribute to nutrient cycling, disease suppression, and overall soil health. The focus on keeping the pile at the right moisture, oxygen and temperature levels allows for the breakdown of organic matter in a way that optimizes biological community composition, generating a nutrient-rich soil amendment that promotes optimal plant and soil health.
Compost extract is an aerobic water-based biological inoculant derived from high-quality mature aerobic compost. Using air pressure (around 80-100 psi), the extract dislodges the beneficial biology present in the compost in a matter of minutes. Compost extract contains high levels of living organisms suspended in water and is typically applied as a soil drench, allowing these organisms to travel deep into the soil where they can support nutrient cycling and plant health. Compost extract offers a convenient and efficient method of delivering a diverse array of beneficial microorganisms to the soil, enhancing nutrient cycling and plant health.
Similar to compost extract, compost tea is an aerobic water-based biological inoculant derived from high-quality mature aerobic compost. Using air pressure, compost tea releases the beneficial biology from the compost. However, unlike compost extract, compost tea involves the addition of food sources to enhance the growth of organisms within the solution. This infusion of nutrients creates a highly potent elixir for foliar application. Compost tea contains growing organisms that are actively producing sticky glues, which allow them to adhere to plant surfaces, facilitating nutrient absorption and offering plant protection.
Biological compost and liquid amendments derived from this amendment, such as compost extract and compost teas, can offer invaluable benefits for sustainable and regenerative agriculture. Biological compost, with its diverse array of locally adapted organisms, provides fuel for a thriving soil ecosystem that supports plant health and biodiversity. Compost extract delivers a concentrated dose of beneficial microorganisms deep into the soil profile, while compost tea provides a nutrient-rich elixir for foliage. Understanding the unique characteristics and applications of each of these inoculants allows for informed decision-making, enabling producers to optimize soil health, plant vitality, and embrace sustainable practices that work within economic realities.
I and my students use quantitative analyses of food and wine production systems to reveal linkages between ecological and social sustainability, “quality”, and the primacy of place … “Ecogastronomy”
Dr. John Volpe