Why do open-field scallion and garlic vegetables from Huangzhong stand out as the best in Qinghai?

In the photo, villagers are planting scallion seedlings in the field.

The Xialu'er Village vegetable production base is one of the earliest protected agriculture bases established in Huangzhong County, Qinghai Province, and is also the largest open-field scallion and garlic vegetable production base in the province. In 2015, the base's cross-village contiguous planting of open-field vegetables reached 6,500 mu. The base adopts a "company + cooperative + farmer" development model and can radiate to and drive 11 surrounding villages. Photo by Gao Jinliang, reporter for this newspaper.