The spatial pattern of agricultural land use in China during the Holocene Megathermal

During the Holocene Megathermal, China entered a stage of extensive agricultural farming, although there are few reports on the possible distribution pattern of agricultural land use. The main objective of this paper is to discuss issues related to the spatial pattern of agricultural land use in China during the Holocene Megathermal. According to historic and archaeological information, three widely planted crops (foxtail millet, broom millet and rice) were selected to represent the main crops, and their distribution was assumed to reflect the agricultural land-use pattern at that time. From the perspective of these crops and their required climate conditions and based on proxy-based ancient temperature and precipitation data combined with modern climate data, an average annual accumulated temperature of >= 10 degrees C in the Holocene Megathermal was retrieved and spatially interpolated to capture a picture of land use. Validation was conducted using archaeological data from 141 agricultural heritage sites. The results indicated that in the Holocene Megathermal, agricultural farming activities were widespread in China The northern-most boundary of agricultural land use was north of Daxinganling, and the southern-most boundary extended to Hainan Island. In the region of the Qinghai-Tibet Plateau where climate is currently much colder than during the Holocene Megathermal, the environment for foxtail millet and broom millet was suitable from the eastern segment of the Qilian Mountains to Lhasa. This study provides a reference for exploring the distribution pattern of agricultural land use in the early period of agricultural production in China and provides useful information for agricultural archaeology.