
http://dsc.discovery.com/news/2006/10/2 ... 1020161530
I knew it had to be good for something besides fertilizer.New evidence from soil inside the remains of a 5,600-year-old corral indicates that the ancient Botai people of Kazakhstan were among the earliest to domesticate horses. But equine romantics might be disappointed to learn that the Botai probably ate and milked their horses as often as they rode them.
That evidence comes from circular arrangements of posts and the soil differences found inside and outside the corral. Inside the corral, the soil contained up to ten times the phosphorus as outside soils, but lower concentrations of nitrogen. That's what you'd expect if the soil there was enriched with horse manure.
Interesting way to 'prove' a theory.Modern horse manure, for comparison, is loaded with phosphorous, potassium and nitrogen. The nitrogen is the easiest to lose to groundwater or the air.
Phosphorus, on the other hand, can be held in place by calcium and iron, says Capo, a geologist who did the soil analyses with Michael Rosenmeier and undergraduates Andy Stiff and James Gardiner of the University of Pittsburgh.
"High phosphorous could also indicate human occupation," said Capo, "but that's usually accompanied by other geochemical signatures, which we didn't find in the corral samples."
There was also high sodium concentration in the corral samples, which could be from urine, suggested Olsen.
