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Agroforestry around the world

I’ve been looking for an excuse to play around with the Database of Places, Language, Culture and Environment (D-PLACE), which “contains cultural, linguistic, environmental and geographic information for over 1400 human ‘societies’”. It finally arrived today, in the form of a monumental study of carbon sequestration on farmland in Nature. The authors used remote sensing and fancy spatial modelling to work out the amount of tree cover, and hence the levels of biomass carbon, on agricultural land around the world. This is the global map they got for % tree cover in 2000 and 2010.

global tree cover

I was curious to see whether one could predict the areas of highest tree cover (or highest biomass C) from the much coarser data on agriculture that D-PLACE brings together from ethnographic studies. This is what the distribution of “major crop type” looks like, from D-PLACE.

agriculture-major-crop-type-map_1_

So the answer is no, I guess. It’s difficult to see any association between the amount of trees on farms and the main types of crops grown there, at least just by eyeballing the maps. There may be a hint of a preference for roots and tubers, but nothing really jumps out. I’ll keep playing though, there’s a whole range of cultural and ecological variables you can tweak.

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Brainfood: Myrciaria value chains, Finger millet WTP, Italian olive choice, Resilience, Rural livelihoods, Ganja conservation strategy, Sorghum erosion

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Brainfood: China cereal yield, US soybean breeding, Breadfruit genomics, Field app, Urban ag, Rose breeding, Strawberry cryo, Global biodiversity loss, Oceania bananas, Vegetable breeding, Badass Chinese sheep

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Ancient agricultural DNA everywhere

Heady days for ancient DNA researchers. There have been two major papers in the past month looking at the DNA of Neolithic farmers. Back in June, a huge research consortium published “The genetic structure of the world’s first farmers” as a preprint in bioRxiv, with subsequent write-up in Nature. And now a different huge consortium comes out with “Early Neolithic genomes from the eastern Fertile Crescent,” in Science. That also got widely picked up.

Don’t ask me why two separate research groups need to be working on basically the same problem, in basically the same way. I suppose they’re using somewhat different methods on different material. I really couldn’t tell you whether it would have been better to pool the material, or standardize the methods, or indeed both. Maybe someone out there will tell us. In any case, it’s reassuring, I suppose, that the two studies came to broadly similar conclusions, namely that there were genetic differences among early farmers, and that genetically distinct people from different parts of the Fertile Crescent migrated north into Europe and eastwards further into Asia. Which in turn suggests to some that the origins of agriculture may be described as “federal”:

Different and genetically distinct populations were all engaged in this same general project, albeit exchanging ideas with each or other or sometimes coming up with the same idea independently.

Meanwhile, sequencing of DNA from a 6000-year-old barley from the Dead Sea shows close similarity with varieties still grown in the southern Levant and Egypt. Intriguing to speculate whether a similar study of material from the Zagros Mountains would show a parallel pattern to the human DNA. But will it need a different group of researchers to do it.