Coffee and charcoal
The UWA club barista was happy to sell coffee to non-members on the promise that a card-carrying one would soon arrive, and so our first meeting began.
After the inevitable housekeeping issues were covered, we were discussing:
Marris, E. 2006. Putting the carbon back: Black is the new green. Nature 442:624-626 (with supporting information from Glaser et al. (2001) below). The main thrust being the terra preta soils of Amazonia, and charcoal additions to soils in general.
It turned out to be a surprisingly small world. Natalie, who has worked in Amazonia, has a colleague who had worked with some of the terra preta enthusiasts mentioned in Ms Marris' article. She mentioned that this sort of issue was "huge" in South America, and confirmed the glassy-eyed enthusiasm of the terra preta crowd.
With global carbon budgets in mind, most of us were impressed with the idea of a carbon-negative process (making soils a net carbon sink, away from earth's atmosphere) that both provides usable fuel and improves soil characteristics.
We debated whether the terra preta phenomenon could be duplicated elsewhere, for example in Australian environments (or Chinese, or anywhere non-tropical) with lower primary productivity. Or, whether terra preta formation could be induced in the short term, given that these soils formed over centuries or millennia. Related to this was whether charring different materials would produce a charcoal with similar properties - and exactly what were the key properties of this stuff, anyway? A comparison was made with soil amendments like zeolites which had no carbon-cycle impact. We wondered about the sorption properties of charcoals in soils for nutrients, trace elements and organic compounds, and how these properties might change during pedogenesis.
The manufacture of charcoal by modern terra preta proponents approximates an efficient cycle by not being optimal for any one component. We wondered whether the same principle could be applied to other systems, like agricultural production.
We wondered and pondered over many things - with no clear answers. We asked excellent questions, though. We'll try to do it again at our next meeting.
PS there is a conference on this stuff coming up soon. See http://www.iaiconference.org/ - commercial entities openly trying to develop systems to mimic terra preta soils.
I have worked at UWA since 1995, coming from New Zealand to take an appointment as Lecturer in the Soil Science group in the former Faculty of Agriculture. I completed my PhD, from Lincoln University in New Zealand, in 1991. If you really want to find out about work stuff go
here. In real life I love my wife, daughter and guitar. Occasionally, I wish I had chosen a career as a carpenter, counsellor or poet.