- Like a deck of cards, we have dealt the last windrow started in early July into the orchard. In the last two weeks, compost which was started on July 2nd has resulted in about 300 tons of material applied as mulch/amendment around trees. New windrows have been started this week and should be ready for spreading in two to three months. The Frog Hollow Compost area will soon double in size because several rows of peach have been removed (these trees were not high producers of fruit).
- About five tons of thermophilic compost were used to cover the vegetable beds prepared by Marlene and Kristin. A week ago this thermophilic compost, which is dominated by fungi, was inoculated with a bacterial tea to make it more bacterially dominated. After a biological analysis, the thermophilic compost was mixed with 20% of vermicompost and applied to the vegetable beds. The compost was screened into small particle sizes using the trommel (rotating screen system) which we normally use for separating worms from their vermicompost. We used a mixture of thermophilic compost and vermicompost because both are aerobic biodegradation processes but each contributes a different set of bionutrients and microbes.
- Last week, we discussed concerns about the presence of plant pathogens and weed seeds in compost that may impact the growth of vegetables. We concluded that composting kills or reduces drastically the levels of plant pathogens. But, if composting kills plant pathogens (or reduces their levels), why aren’t beneficial microbes killed? What mechanisms operate in composting to selectively limit the growth of plant pathogens? The eradication of plant pathogens from organic residues is primarily due to: heat generated during composting (pathogens appear to be more sensitive to heat); the production of various acids and gases that are toxic to pathogens; release of enzymes by beneficial lmicrobes that attack the pathogens; production of antibiotics by beneficial microbes. Finally, if the starting materials in a compost pile come from pathogen- free sources (are not contaminated with pathogens), the healthy microbes outnumber the pathogenic microbes in the competition for energy. Also, pathogens require certain specific environmental conditions to infect a plant (such as mild temperatures and humidity) and remain infectious. These conditions do not exist in a compost pile.
Author: Christophe Kreis MLF Soil Consulting PhD, Molecular Biology/Developmental Biology, University of British Columbia, Canada. Christophe is co-founder of MLF Soil Consulting with his wife Monique. He started his career in basic medical research and after various positions in academia and industry Christophe slowly returned to his first passion Soil Ecology and Microbiology. It is his belief that human health is tied intimately to soil health through the production of healthy food. For this reason MLF Soil Consulting is committed to help farmers improve the management of their soil through composting, vermicomposting and biological analysis of microbial soil life.