Tea Time for Fungi at Frog Hollow Farm

• Last week, compost and vermicompost were added to the new vegetable beds. As soon as possible, soil samples will be taken from these beds and a biological assessment (biomass, biological diversity) will be made. Water extractable nutrients will also be analyzed using a chemical test. Throughout the fall/winter season, periodic analyses will be made to see how the biomass is changing and of course Marlene and Kristin will be monitoring the growth and yields of their vegetable crops. We will see how the biological/chemical properties of soil are affected by compost/vermicompost additions and how these compare with plant growth and yield.

• This week our assistant farmers will be planting some of their transplants and also do some direct seeding. Vermicompost tea dominated by bacteria is being prepared. To this tea will be added a type of fungus called mycorrhizae (a beneficial fungus that colonizes the roots of most plants). The roots of the transplants will be dipped in this tea just before planting. On the other hand, seeds will be placed in a moist bag and will be shaken in the presence of pellets of mycorrhizae which will stick to the seeds. They will then be sowed into the vegetable beds. Various types of mycorrhizae have been shown to form a mutualistic relationship with the roots of most plants: the mycorrhizal fungus colonizes or “infects” a plant root and what follows is an exchange of carbon, micronutirents and possibly water. Carbon is transferred to the fungus from the plant in the form of sugars. Micronutrients such as phosphorus, nitrogen, zinc, sulfur and very likely calcium are transferred to the plant. There is also evidence that water may be transported from the fungus to the plant. The mycorrhizae can be considered an extension of roots: they are thinner than roots and so can access nutrients in pores of the soil that are inaccessible to plant roots. The roots of some trees at Frog Hollow have been analyzed for mycorrhizal colonization: some have good colonization and some have low colonization. We don’t know if mycorrhizal colonization is good or low in the area of the vegetable beds. So, we are applying the mycorrhizae pre-emptively and once we get vegetables growing, we will analyze their roots for mycorrhizal colonization. The effects of mycorrhizal associations on vegetable production are almost all potentially beneficial, with only a few reports of growth depressions in agricultural field situations. Plant-mycorrhizal associations contribute to nutrient and water uptake in all types of crops and consequently this may lower the need for external applications of various micronutients.

• Farmer Al announced last week that he is planning to expand the vermicomposting area. We presently have four 100 foot beds composting at any one time. If the expansion proceeds, we will have an additional 200-400 feet under the poplar trees. One reason for this expansion is to add vermicompost with its live worms to the equivalent of 1000 planting holes where new trees will be planted (1000 trees have been removed for a variety of reasons). A similar experiment has been performed a the beginning of this year (described in the first blog of this year) and it seems to be working.

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.

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