Dry-wet change in the ecotone between farming and animal husbandry along
the Great Wall of China between 1540 and 2019
Abstract
The research on the periodic change of dry-wet has significance to study
the regional response research of climate change. In the ecotone between
agriculture and animal husbandry along the Great Wall of China,The ring
width index of the Carya Cathayensis is fitted with the rain-factor
index (R) calculated by the nearest Qinglong meteorological station. The
R is divided into different cycles by the stepwise function fitting
method. The results show that there are two dry cycles and one wet cycle
from 1543 to 2019. In each dry and wet cycle, there are also different
cycles, such as long (decade years), intermediate (ten years) and short
cycles (several years). Drought is a greater threat to agricultural
production in the region and even China. In the first dry cycle
(1543-1756), 4 cycles (1633-1635: R = 30, 1636-1939: R = 26, 1640-1642:
R = 9 and 1643-1645: R = 24) with low R appear continuously, the severe
droughts (R < 20, no rain in a year) last 13 years. The cycles
of dry-wet changes are consistent with the traditional Chinese calendar.
The results can be used to make necessary preparations for effectively
coping with the drought and flood.