Editing Domestication of the horse (section)

===Dung and corrals===
[[Soil scientist]]s working with Sandra Olsen of the [[Carnegie Museum of Natural History]] at the [[Chalcolithic]] settlements of Botai and [[Krasnyi Yar (Kazakhstan)|Krasnyi Yar]] in northern Kazakhstan found layers of horse dung, discarded in unused house pits in both settlements.<!--dated to when??--><ref name="French2003">{{cite book |title=Prehistoric Steppe Adaptation and the Horse |last=French |first=Charly |author2=Kousoulakou, Maria |editor=Levine, Marsha |editor2=Renfrew, Colin |editor3=Boyle, Katie |year=2003 |publisher=McDonald Institute |location=Cambridge |isbn=978-1-902937-09-0 |pages=105–114 |chapter=Geomorphological and micromorphological investigations of paleosols, valley sediments, and a sunken-floored dwelling at Botai, Kazakstan }}</ref> The collection and disposal of horse dung suggests that horses were confined in corrals or stables. An actual corral, dated to 3500–3000 BCE was identified at Krasnyi Yar by a pattern of post holes for a circular fence, with the [[soil]]s inside the fence yielding ten times more [[phosphorus]] than the soils outside. The phosphorus could represent the remains of manure.<ref name="Olsen2006">{{cite conference |first=Sandra L. |last=Olsen |title=Geochemical evidence of possible horse domestication at the Copper Age Botai settlement of Krasnyi Yar, Kazakhstan |conference=Geological Society of America Annual Meeting |date=2006-10-23 }}</ref>