What doesn't get traded

Corn appears to have been bred about 7000BC, and spread south: Ecuador 6000BC ± N lower Central America 5600BC, Columbian Andes 4500BC ± N -- New Mexico and Arizona about 2500BC, and to reach beyond the desert took more than 2500 more years.

Seeds are easy to pack, and if you keep them dry they ought to keep a long while. But the "how to grow" them might be a little less portable, if traders weren't usually farmers.

Transfer of knowledge and plants is trivial if the farmers migrate or intermarry along the routes, straightforward if trading travel is part-time or everybody learns a bit of everything, and hard if trading is a specialization, or if the people you trade with aren't really into agriculture on a large scale.

I wonder what the barriers were that slowed corn reaching far into North America. Desert would be one, obviously. Were the deserts and jungles of those eras in the same places as now? I've done a little searching, and so far haven't found systematic climate studies that cover enough of the area to game out which way people might go. If somebody knows, I'm curious. Up and down the coast should be pretty straightforward.

Remote areas having nothing you cared to cart back is another barrier, as are hostiles. Great Lakes copper went east, south to Georgia, north to Alaska--but I don't see references to the SouthWest. Well after Great Lakes copper started being used, South American started smelting their own--and possibly that was easier to get than stuff from the north. But one map on that page shows marine shells being traded across the deserts, so trade wasn't impossible.

Of course, the trade routes may have developed later than the movement of corn growing, which happened pretty early in most places.

I got started down a rabbit hole trying to figure out how trade worked from the Pacific to the Amazon side of the Andes. Incas traded for feathers and skins, and even tried to invade--how old were the trade routes? Would they have been possible for the Caral-Supe, circa 3500BC, 3000 to 4700 years earlier?

Antibiotics on the farm

We now know that antibiotics were overused and that we're suffering because of it. When I first heard of their use, I wondered why farmers wanted to be so pro-active. Why not just treat them when they get sick? I was disabused of that misunderstanding.

The antibiotics promote growth in livestock. The headline in that article says "fatten" but the growth gave less fat and more protein. Nobody knows why.

Maybe it does something to the gut bacteria -- for mice low antibiotic doses make them obese, and a microbiome transplant from the obsese mouse to untreated ones makes them obese. But that "obesity transplant" can happen with people in other situations, so it may not be directly related.

Directly trying to directly measure the gut bacteria of steers doesn't show very much--probably because they only look at a few strains.

Maybe fewer bacteria in the gut means you get more of the nutrition yourself. The second link has a list of 11 possible mechanisms people have investigated.

Maybe, as the first link suggests, it might not be important anymore, thanks to better overall nutrition any hygiene for hogs. Or maybe a 16% average weight gain is important enough that farmers are still using them, despite the rules against it.

They do it better

Here in Wisconsin we have corn mazes in the fall. In Japan, on the other hand... True, their artwork isn't interactive, but it beats crop circles.

They use different colors of rice plant to get different colors.

For some reason the link text includes "Chinese" rather than "Japanese."

If you missed seeing it before, look at Simon Beck's snow art.

Grinding

We were looking at grain grinding stones in the AmerIndian section of the Milwaukee museum. Not a sign of a rotary mill in sight. Was it obvious why?

The go-to place to look for inventions is usually China. The Mo was developed around 250BC.
That's pretty recent.

However, it looks like Greeks in about 400's BC invented a hopper mill (grain fed through a hole in the top stone), and somebody in Spain probably invented a rotary mill about the same time. The diffusion must have gone the other way this time.

This source suggests that the requirements of olive processing demanded innovations in milling that some clever folks transferred to grinding grain.

The rotary quern and rotary mill aren't very suitable for processing the typical crops of African rainforests, so is isn't surprising not to find them there. And since they were invented so recently they'd have to have been re-invented in the Americas--but they weren't. The labor needed to make one wouldn't seem likely to pay off quickly unless more than just a couple of families were grinding their grain with it. Several AmerIndian cultures had densely populated farming sites, so they could certainly have used it if they had it.

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As a side note, I was curious about where North American Indians got their beans: ""These four cultivated species have similar origins in the Americas, tepary found in NW Mexico and southern Arizona, scarlet runner and year-beans found in Southern Mexico and the highlands of Guatemala and the lima bean mirrors the common bean in that it has two centers of origin: one in Andean region and the other in Middle America." I knew about the Andes and Central America, but not New Mexico. Obviously the seeds went all over the place--I have no idea how quickly, though. I wonder if anybody has been able to trace that spread.