What counties are there in Changsha, Hunan?
1. Geological characteristics:
The geological characteristics of Changsha are: the strata are completely exposed, the granite bodies are widely distributed, and the geological structure is complex. Various geological and historical strata are exposed in Changsha, and the oldest stratum was formed about 1 100 million years ago. About 600 million years ago, Changsha was still a sea of Wang Yang, but the sea was not deep. After that, the sea gradually withdrew from east to west, and most areas of Liuyang, Changsha and Wangcheng surfaced, becoming the northwest edge of Jiangnan ancient land. About/kloc-0.40 billion years ago, the seawater immersion in Changsha area ended and rose to land. Due to the influence of crustal movement and geological structure, a long-strip intermountain depression basin-Chang (Sha) Ping (Jiang) basin has been formed. Since Cenozoic, the whole Changping basin has risen to land. About 3.5 million years ago, the third ice age occurred on the earth, and Liuyang preserved the remains of glacial landforms.
2. Terrain:
The overall characteristics of Changsha landform are: large ups and downs, diverse landforms and developed surface water system. The northeast of Changsha is the northern section of the shogunate-Luo Xiao mountain system, the northwest is the eastern edge of Xuefeng Mountain, and the middle is the transition zone from Heng Chang hilly basin to Dongting Lake Plain. Surrounded by mountains at both ends of the northeast and northwest, the terrain is steep, and the middle gradually declines and tends to be flat, just like a saddle shape. Xiangjiang River runs obliquely through the central part from south to north, with rolling hills in the south and flat and open terrain in the north, which is shaped like a funnel opening to the north. The city consists of multi-level terraces with gentle slopes, and Orange Island in Xiangjiang River is 5 kilometers long.
3. Climate environment:
Changsha has a subtropical monsoon climate with mild climate, abundant precipitation, simultaneous rain and heat, and distinct four seasons. The annual average temperature in Changsha is 17.2℃, the annual accumulated temperature in each county is 5457℃, the annual average precipitation in urban area is 136 1.6 mm, and the annual average precipitation in each county is 1358.6 ~ 65438. Changsha is long in summer and short in spring and autumn, with about 1 18- 127 days in summer, 1 17- 122 days in winter and 6 1-64 days in spring. The temperature changes greatly in spring, with more rain in early summer, long high temperature in summer and autumn and less cold in winter. From late March to mid-May, cold and warm air crossed each other, forming continuous rainy and low temperature weather. Since the end of May, the temperature has obviously increased. In summer, the average daily temperature is above 30℃ for 85 days, and in hot days above 35℃, the average annual temperature is about 30 days, and it is very hot and rainy in summer. After the end of September, it is warmer during the day and cooler at night, with less precipitation and more low clouds. 165438+ 1 from late October to mid-March of the following year, the severe cold period in Changsha is very short, and1is the coldest in June, with a monthly average of 4.4℃-5. 1℃. Overwintering crops can safely overwinter and grow slowly.
4. Soil environment:
There are various soil types in Changsha, which can be divided into 9 soil types, 2 1 subclass, 85 soil genera, and 22 1 soil type, with a total area of 13662 mu, in which red soil and paddy soil account for 70% and 25% of the total soil area respectively. The rest are vegetable garden soil, fluvo-aquic soil, mountain yellow soil, yellow brown soil, mountain meadow soil, lime soil and purple soil, which are suitable for the growth of various crops.