Fig. 3.

The growing niche of broomcorn millet, foxtail millet, and wheat and barley in the region of study using GDD as a measure at modern temperatures. The areas where each crop can be cultivated successfully are shown in red. The border zone for cultivable viability is shown in white. It may be possible to cultivate some varieties in this area. The crop represented cannot be cultivated in the area shown in blue. The black-bordered box represents the NETP. Black dots represent archaeological sites discussed in the text: 1, Ashaonao; 2, Yingpanshan; 3, Haxiu; and 4, Karuo.