This is a very big meeting, but I was surprised by how much I’ve started to recognize people after just a couple years of going to these meetings. UW had a large contingent from Soils and a few from Agronomy as well.
I found that my highlights were talks which asked big questions and didn’t get around to answering them. I went to a forest soils symposium and really enjoyed how these scientists approached soil C. Knutte Nadelhoffer talked about this DIRT (Detritus Input Removal and Transfer) network started by Francis Hole here at the Arb, where they manipulated inputs in a forest setting. The Arb experiment ended in after 50 years, but others are ongoing at Harvard, Oregon, Hungary, a few other places, and results are varied. At the Harvard forest, changing inputs only affected SOC in the O horizon after 20 years. Susan Crow has a 2009 paper about the SOC chemistry changing at the Oregon site and found some evidence for priming where litter inputs were increased.
Markus Kleber challenged my burgeoning organic chemistry understanding by trying to lay out some steps through which SOM must pass in order to become “stablized”, emphasizing that since OM is 80% insoluble material, the first step is to oxidize it into solubilization. In the end, he encouraged us to think about SOC as a flow, rather than a storehouse. In that light, my aggregate data could be seen as properties which regulate flow of OM, rather than locations where OM can be stored.
My talk went fine, and I had a good poster session, especially talking over my work with Kieth Paustian, who was one of the first aggregate fractionators. I also enjoyed talking with Steve Culman, the fertility specialist at Ohio State who’s also done some work with The Land Institute’s perennial crops. He’s organizing a grow-out of Kernza as a forage across the midwest. I enjoy explaining how we got to the correlations we did between yield and SOM fractions, and it’s a fun thing to present this data that’s pretty open to more questions.
Last highlight was John Norman, who questioned whether it is appropriate to assume that the observer is independent of what they are observing. This really brings quantum physics to bear on our macro-scale science, and it’s a fascinating question to ponder. If experience and thoughts can shift our DNA, it seems they could also shift how we observe plant growth or program a Li-Cor, but I am not sure what you could do to reduce that effect. I appreciated Norman’s bringing something completely different into the soil science sphere.