*2.1. Geographical Conditions*

The Hetao Basin is located in the central and western regions of the Inner Mongolia Autonomous Region (106◦070~112◦150 E, 40◦100~41◦270 N, Figure 1), stretching from the Ulanbuh Desert in the west to the west foot of the Manhan Mountain in the east, as well as from the Yinshan Mountains in the north to the Ordos Plateau in the south, which takes up a total area of nearly 3.2 <sup>×</sup> 104 km<sup>2</sup> . It has been recognized as a vital grain production base in China and the most developed socio-economic area in the Inner Mongolia Autonomous Region, involving Hohhot (the capital city of the Inner Mongolia Autonomous Region) and Baotou (the largest industrial city in the Autonomous Region). Such an area is characterized by an average annual temperature of 6.5–7.8 ◦C, with an average monthly maximal temperature of 22.4 ◦C (July) and an average monthly minimum temperature of −12.0 ◦C (January). On average, the annual precipitation is 245.5 mm, and the annual precipitation of the eastern part exceeds the western part. The evaporation in the eastern part is 2185.2 mm, lower than that of the western part [38,39]. The Yellow River is known as the only perennial river in the study area, flowing from the west to the east via the whole area, and the other large seasonal rivers consist of the Dahei River and the Kundulun River [40].

**Figure 1.** Geologic and geomorphologic map of the Hetao Basin.
