Biodynamics, compost and soil microbiology

Nigel Sowman of Dog Point Vineyard in Marlborough, New Zealand told me (20 July 2014 in Marlborough) that ‘when making compost our goal is to push both the vines and the soil towards fungal dominance because that is how the vines, being a woody species, like it. Probably my biggest bugbear against going biodynamic is that the preparations often appear to be more geared to home gardens, and plants with tight root systems which are very bacterially dominant. Cow manure will make the soil go more bacterial because of its nitrogen component. However, as I am growing a woody plant on a trellis a fungal-dominated soil will suit my vines much better than one with a bacterial dominance, hence the need to avoid increasing the bacterial dominance of my soil via manure-based compost. Having done a lot of soil testing with the Soil Food Web I know I already have a very bacterially dominant soil here in Marlborough. So I am actively trying to get more fungi, mychorrizal fungi (which survive on plant roots) or any cellulose digesting fungi, into my soil. I want to avoid anything that pulls me away from that goal of pushing towards fungal dominance, via mychorriza or any cellulose-digesting fungi. When our compost piles go cold it signifies that the piles have gone through most of their composting process. At this point I go to a native forest nearby to collect leaf litter. If you pull back the leaf litter you can see the white mycelium on it. We collect the leaf litter, and add it to the compost by making holes along the piles in which we bury the leaf litter. This re-inoculates the pile–even though it is has nearly finished its composting process–with composting or cellulose digesting fungi, promoting species diversity of fungi that will creep through the pile too. My best composts have always been those I have left a little bit longer and been able to use this technique with.’

See compost tea.