China's three major silkworm areas are Sichuan Basin, Taihu Plain and which areas?

Sichuan basin:

Sichuan Basin, also known as envelope basin, purple basin and red basin, is one of the four great basin in China, including the central and eastern Sichuan Province and most parts of Chongqing, located in the upper reaches of the Yangtze River, with an altitude of about 500 meters. It is located in the south-central part of the Asian continent, in the heart of China and in the middle of the eastern edge of China, surrounded by connected mountains. The total area is about 260,000 square kilometers, which can be clearly divided into two parts: marginal mountain and basin bottom, with an area of about 654.38+ and 654.38+0.6 million square kilometers respectively. Generally, there are 2 ~ 5 vertical natural zones from bottom to top in marginal mountainous areas. The bottom of Sichuan Basin is divided into three parts: parallel ridges and valleys in eastern Sichuan, hills in central Sichuan and Chengdu Plain in western Sichuan. The main cities in the basin are Chongqing and Chengdu, and Zigong, Luzhou, Deyang, Mianyang, Guangyuan, Suining, Neijiang, Leshan, Yibin, Nanchong, Guang 'an, Dazhou, Ya 'an, Bazhong, Meishan and Ziyang in Sichuan Province. The culture is Shu culture. Generally speaking, the climate of the basin belongs to subtropical monsoon humid climate, but most areas of the basin are similar to temperate maritime climate.

Sichuan Basin is the home of most people in Sichuan and Chongqing, one of the most densely populated areas in China and even the world, and the cradle of Bashu culture. Among them, Chengdu Plain is called "Land of Abundance". Zhuge Liang, the prime minister of Shu, once praised it as "fertile soil for thousands of miles". China is a famous red bed basin with the most typical shape, the southernmost latitude and the lowest elevation in the great basin of China. Covering the central and eastern Sichuan Province and most parts of Chongqing, it is located in the upper reaches of the Yangtze River at an altitude of about 500 meters. The Yangtze River connects it with the East China Sea, which is the largest outflow basin in China.

Taihu plain:

Taihu Plain is located in the south of Yangtze River in Jiangsu Province, China, north of Qiantang River in Zhejiang Province, west of East China Sea and east of Tianmu Mountain. It is a dish-shaped depression centered on Taihu Lake.

In Taihu Plain, the height of the plate edge is only 4 ~ 10 m, most of which is 4 ~ 6 m, and the lowest place in the depression is 1.7 m.. Many isolated mountain ranges are distributed on the plain. Generally below 200 meters, Taihu Lake has 9 1 islands. There are groups of lakes and rivers criss-crossing, as dense as cobwebs. The length of rivers is about 40,000 kilometers, and there are more than 250 large lakes. Taihu Lake covers an area of 2,425 square kilometers with an average water depth of 2. 1 meter. There are Gehu Lake and Changdang Lake in the west, Yangcheng Lake, Hucheng Lake and Dianshan Lake in the east, forming a group of lakes centered on Taihu Lake.

Taihu Plain is located in the Taihu Lake Basin, starting from the Yangtze River in the north, east to the East China Sea, south to Qiantang River and Hangzhou Bay, and west to Tianmu Mountain and its branches, separated from mountainous areas in southern Anhui and Ningzhen hills, including Hangzhou, Jiaxing and Huzhou in Zhejiang Province, Suzhou, Wuxi, Changzhou, Danyang and Shanghai in Jiangsu Province.

? The inland river network in Taihu Plain is dense, and countless rivers such as the Yangtze River and Jiangnan Canal pass through it. Taihu Plain is a commodity grain base in China, and it has been the main grain source of China royal family and army since the Six Dynasties.

The Pearl River Delta, formerly known as the Yuejiang Plain, is located in the south-central part of Guangdong Province, adjacent to the South China Sea. East from Dongjiang Shilong, west to Xijiang Antelope Gorge, north to Beijiang Lubao and south to the South China Sea coast. It is a composite delta formed by the common alluvial of Xijiang, Beijiang and Dongjiang, the three tributaries of the Pearl River, in Shuigu Bay. Located in the south of the Tropic of Cancer, it belongs to the humid monsoon climate in the south subtropical zone and is the largest alluvial plain in the south subtropical zone of China. [1] The Pearl River Delta includes nine prefecture-level cities along the Pearl River, namely Guangzhou, Shenzhen, Zhuhai, Foshan, Huizhou, Dongguan, Zhongshan, Jiangmen and Zhaoqing. It has jurisdiction over 33 municipal districts, 5 county-level cities, 7 counties, 320 towns, 267 streets and 2 ethnic townships, with a total land area of 54,700 square kilometers. [2] The registered population is 3,200. [4] 1985 1, the State Council proposed that the Pearl River Delta should be regarded as a coastal open area, with a "small triangle" first and then a "big triangle", and the layout should be carried out step by step and in a planned way. 199410/0 On October 8th, the Guangdong Provincial Party Committee proposed to establish the Pearl River Delta Economic Zone at the Third Plenary Session of the Seventh Central Committee. In July, 2003, Guangdong Provincial Committee formally put forward the concept of "Pan-Pearl River Delta" for the first time. In June 2004, the first Pan-Pearl River Delta Regional Cooperation and Development Forum was held. [5]

Chinese name

Chu Chiang Delta

Foreign name

Pearl River Delta in China

Another name

Pearl River Delta

Administrative category

Region, Metropolitan Area and Urban Agglomeration

Belonging area

The south of China

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brief introduction

Chu Chiang Delta

The Pearl River in China is a delta formed by alluvial deposits in the middle of Guangdong. It is composed of three small deltas alluvial by Xijiang River, Beijiang River and Dongjiang River, with an area of about 1. 1.3 million square kilometers. The Xijiang River and Beijiang River Delta account for110. There are more than 160 bedrock mounds in the delta, about 6000 years ago. It was originally an island in a shallow bay in 2000. There is not much sediment in the Pearl River, and the annual total sediment is only 65438+ 100 million tons. Shallow bays with many islands are conducive to sediment stagnation, so the delta has developed rapidly in the past 2000 years. Canqiu is 300 meters above sea level? 500 meters often becomes a beautiful scenic spot, such as Xiqiao Mountain, Wugui Mountain and Yashan Mountain.

Chu Chiang Delta

Formerly known as Yuejiang Plain. The Pearl River Delta for short. Located in the eastern coast of Guangdong Province, China, it is a delta complex with radial estuary, which is the general name of the large delta formed by simultaneous alluvial of Xijiang River and Beijiang River and the small delta formed by alluvial of Dongjiang River. It is an inverted triangle, with the bottom line starting from Sanshui City in the west, Guangzhou City in the east, and Shilong, with the apex at Yamenwan. The area is about 1. 1 10,000 square kilometers. Alluvium is thin, generally 20 ~ 30 meters. The ground fluctuates greatly, surrounded by hills, mountains and islands, accounting for 30% of the area. The central part is plain, distributed in southern Guangzhou, northern Zhongshan, eastern Jiangmen and western Humen. The annual sediment transport capacity of the Pearl River system is more than 80 million tons, and the delta near the estuary is still extending to the South China Sea. Hekou District can extend 65,438+00 ~ 65,438+020 meters every year, which is one of the key reclamation areas in China. The delta has a subtropical climate, which is warm and humid all year round. The annual average temperature is 2 1 ~ 23℃, with the highest Leng Yue 13 ~ 15℃ and the hottest month above 28℃. There are frequent typhoons from June to 10, with concentrated rainfall and the hottest weather. The annual average precipitation exceeds1500mm. The rainy season is synchronized with the high temperature season, with fertile soil and rivers, which is beneficial to agriculture. The yield per unit area of rice is among the best in China. Tropical and subtropical fruits include litchi, citrus, banana, pineapple, longan, carambola, mango, grapefruit and lemon. Three-dimensional agricultural structures such as mulberry-based fish ponds, fruit-based fish ponds and sugarcane-based fish ponds have been developed, which has become a model of ecological agriculture in China. There are sugar, silk, food, paper, machinery, chemicals, building materials, shipbuilding and other industries, known as the pearl of the South China Sea.

At present, there are nearly 100 large waterways in the delta, and there are more smaller ports interwoven into a network. The Pearl River enters the sea through eight gates respectively. There are often residual hills at the sea, and the situation is dangerous, which is called "door". The famous ones are Humen, Modaomen and Yamen. Due to the different separation conditions of water and sediment, the sedimentation rate of each inlet is also different. The Wanqingsha between Jiaomen and Li Hongqi increased by 1 10 m on average every year, and the lantern sand in Modaomen was 80? 100 m, Humen and Hutiaomen are insufficient 10 m. The Pearl River Delta is located in the south subtropical zone, and the local people have created management modes such as "Sangji Fish Pond", "Fruit Fish Pond" and "Sugarcane Fish Pond", which not only make use of superior natural conditions, but also protect the agricultural ecosystem. In addition, due to the construction of dikes and the establishment of electronic irrigation and drainage systems, floods and tides have been prevented and the development of agriculture has been promoted. Rich in rice, sugar cane, cocoon, jute, banana, pineapple, papaya, litchi, longan, orange, lemon and so on. Freshwater fishery is also called developed.

Since 1980s, it has become one of the fastest growing regions in China by taking advantage of the national policy advantages and strong geographical conditions. At present, economic strength still has great influence in our country. The Pearl River Delta has developed light industry, including sugar, silk, food, paper, machinery, chemicals, building materials, shipbuilding and other industries, and is known as the pearl of the South China Sea. In recent years, three-dimensional agricultural structures such as mulberry-based fish ponds, fruit-based fish ponds and sugarcane-based fish ponds have developed rapidly. "Greater Pearl River Delta" refers to the region composed of Guangdong, Hong Kong and Macao. The "Greater Pearl River Delta" covers an area of 18. 1 1,000 square kilometers. From the perspective of economic scale, the "Greater Pearl River Delta" is equivalent to 1.2 times that of the Yangtze River Delta. The "Greater Pearl River Delta" has become the third largest metropolitan group in the world.