What differentiates people from the north and south? Dumplings or tofu pudding? Neither! Actually, it’s this!

In middle school geography class, we all learned that "the Qinling Mountains and the Huaihe River are the dividing line between north and south China."

But if you think it is a clear "line", you underestimate the complexity of geography.

01

Qinling Mountains is a "surface"

Let's talk about the Qinling Mountains first. The Qinling Mountains in a broad sense refers to a huge east-west mountain range that stretches across central China, starting from the Dieshan Mountains in Gansu Province and dividing it from the Kunlun Mountains in the west, and running eastward through the Maiji Mountains in southern Tianshui into Shaanxi.

Schematic diagram of the location of Qinling Mountains. Image source: Paprika

The Qinling Mountains are divided into three branches at the border between Shaanxi and Henan. The northern branch is Xiaoshan Mountain, and its remaining branches extend eastward along the south bank of the Yellow River, commonly known as Mangshan Mountain; the middle branch is Xiong'er Mountain; and the southern branch is Funiushan Mountain. A small part of the southern part of the mountain range extends from Shaanxi to Yunxian County, Hubei, with a total length of 1,600 kilometers and a width of tens of kilometers to 200 to 300 kilometers from north to south. It is vast, majestic, and spectacular.

Taibai Mountain is the main peak of Qinling Mountains.

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The Qinling Mountains in a narrow sense refer to the middle section of the Qinling Mountains located in Shaanxi Province, which is also the main body of the Qinling Mountains . It is about 400-500 kilometers long from east to west, 100-200 kilometers wide from north to south, and generally 2000-3000 meters above sea level. The main peak , Mount Taibai , has an altitude of 3767 meters, making it the highest mountain in central and eastern China with majestic scenery.

Even the narrow Qinling Mountains are about one or two hundred kilometers wide, so where is the dividing line between the north and the south?

Generally speaking, this important dividing line should be located at the ridge, so as to ensure the integrity of the vertical natural zones on both sides of the mountain. But the embarrassing thing is that the Qinling Mountains do not have a clear ridgeline . Even if the highest points of the high-altitude peaks are connected, what is obtained is not a "line", but more like a "net".

The autumn scenery of Qinling Mountains.

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The Qinling Mountains have a complex terrain, and the geographical community has never stopped arguing about it.

Some people advocate drawing the north-south dividing line at the 800-meter contour line on the south slope , because as the altitude increases, the temperature drops, and typical subtropical plants begin to disappear here, and the north should start from here. Others advocate drawing the north-south dividing line at 700 meters on the north slope , because the warm temperate zone ends here, and the climate above should be considered mountainous.

Each view has its scientific basis, which is why the true dividing line has always been confusing. Why did the burden of dividing the north and the south fall on the Qinling Mountains?

Qinling Mountain Highway.

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The Qinling Mountains just happen to grow at a critical point.

Qinling Mountains is located in an important part of the Central Orogenic Belt on the geological map of China, a key area where the Central Orogenic Belt and the North-South Tectonic Belt meet . There are not only many geological periods, but also many geological phenomena such as magmatic activities, geological deformation, rock metamorphism, and new mineral formation. The steep north slope is full of canyons and steep mountains.

The Qinling Mountains are a large natural barrier. In summer, it prevents humid ocean air from penetrating deeply into the northwest, making the northern climate dry. In winter, it blocks the southward invasion of cold air, making the Hanzhong Basin and Sichuan Basin less affected by cold air.

Mount Hua is part of the Qinling mountain range.

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Due to the blocking effect on water vapor, the average precipitation on the southern slope of Qinling Mountains is more than 800 mm, while the average precipitation on the northern slope is less than 800 mm . The northern slope of Qinling Mountains is relatively cold and dry, while the southern slope is warm and humid, forming an important boundary between the warm temperate semi-humid climate zone and the subtropical monsoon humid climate zone.

The southern slope of Qinling Mountains is divided into five climate zones from bottom to top: subtropical, warm temperate, temperate, cold temperate, and subarctic; the northern slope is divided into four climate zones from bottom to top: warm temperate, temperate, cold temperate, and subarctic. The temperature difference between the north and south slopes is large, reaching 6-7 degrees Celsius.

The Qinling Mountains are also home to many rare wild animals, especially the Qinling giant pandas, which is the northernmost boundary of the distribution of giant pandas in China and the area with the highest density of wild giant pandas in the world.

Sichuan golden monkey in Qinling Mountains.

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The last of the world's rare birds, the Crested Ibis, was discovered by scientists in Yang County on the southern slope of the middle section of the Qinling Mountains. After more than 30 years of local protection and artificial breeding, the population has reached nearly 2,000, and the Qinling Mountains have become its excellent habitat. The Qinling Golden Monkey is also widely distributed on both the north and south sides.

The largest wild animal in Qinling Mountains, the Qinling takin, can be seen everywhere. Giant pandas, golden monkeys, takin and crested ibis are known as the "four national treasures" of Qinling Mountains.

02

The Huai River is so "tangled"

The Qinling Mountains are a huge mountain range after all, which blocks airflow. Why can the Huaihe River, a river on the plain, also become the dividing line between the north and the south?

There is no big difference in natural vegetation and crops between Huainan and Huaibei on both sides of the Huai River. But if you go a few hundred kilometers further north and south, the difference becomes obvious. For example, Yangzhou on the south side of the Huai River and Zhengzhou on the north side of the Huai River have a very clear distinction between the south and the north.

Part of the Huai River Basin. Image source: Paprika

The common people on both sides of the Huai River call it the "Bad River", which has a rather gnashing meaning.

Because the floods in this river are so serious, there were more than 70 floods every 100 years on average from 1400 to 1900. The heaviest rainstorm in mainland China's meteorological records occurred in the upper reaches of the Huaihe River in 1975. In Linzhuang, the center of the rainstorm, the total precipitation in three days reached 1,605 mm.

Since the Huaihe River is the dividing line between the north and the south, its tributaries naturally have the characteristics of both the north and the south. It has both the large precipitation variability and concentrated rainstorms in the north and the long-lasting and strong rainstorms in the south. From the perspective of disaster science, the intersection of natural zones is often a high-incidence area for natural disasters. Therefore, the Huaihe River is particularly prone to major floods.

Sunset on the Huai River.

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What is even more worrying is that the Huaihe River has no downstream.

In order to prevent the invasion of Jin soldiers, the Southern Song Dynasty dug up the southern dike of the Yellow River, but it not only failed to stop the Jin soldiers, but also allowed the Yellow River to seize the estuary of the Huai River. The Huai River was depressed, and the flood became more serious.

After the Yellow River was redirected back to the Bohai Sea, the silt left behind still accumulated in the lower reaches of the Huai River, making it difficult for it to enter the sea. The Huai River struggled to cross the huge Hongze Lake and enter the sea through artificial canals and several small streams.

Fishing boats on the Huai River.

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The artificial dam of Hongze Lake completely blocked the only remaining outlet of the Huai River, and the river water could only flow into the artificially dug Subei Irrigation Canal and Grand Canal. Geographical circles had no choice but to regard the Subei Irrigation Canal as the lower reaches of the Huai River and identify it as the dividing line between the north and the south , although its direction was not completely east-west.

03

How to divide it?

You may ask, since the Qinling-Huaihe line is so chaotic, is it really appropriate to use it as the north-south dividing line?

In fact, this line is the most accurate way to divide the area . When you cross the vast Qinling Mountains, you can see the difference in vegetation on both sides. Plants such as oranges that are suitable for growing in the south are almost no longer found north of the Qinling Mountains. Although the vegetation on both sides of the Huaihe River is not much different, if you extend it from here to the north and south for hundreds of kilometers, you can see a bigger and bigger difference.

Mount Hua, famous for its danger, is part of the Qinling Mountains.

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The two most important rivers in the north and south of my country are the Yangtze River and the Yellow River. The Qinling Mountains are the watershed between the Yangtze River and the Yellow River. The Wei River, the largest tributary of the Yellow River, originates in the Qinling Mountains, with a total length of more than 800 kilometers. After entering Shaanxi from Gansu, the Guanzhong Plain formed by the alluvial deposits of the Wei River is known as the "Eight Hundred Miles of Qinchuan".

The Han River and Jialing River, two major tributaries of the Yangtze River, also originate in the Qinling Mountains. The Han River forms the Hanzhong Basin and the narrow Hanshui Valley to the east. It is known as the Jiangnan of the Northwest and is a land of fish and rice.

The Chihai Lake on Taibai Mountain, the main peak of the Qinling Mountains, is a cirque lake formed during the Quaternary glacial activity.

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The Han River and Jialing River south of the Qinling Mountains have lush vegetation on both sides, weak soil erosion, and low sediment content, so the water is as clear as jade. Therefore, the South-to-North Water Diversion Project needs to divert water from the Han River to Beijing, and this area has become Beijing's water source area. However, the Wei River north of the Qinling Mountains has turbid water, which is better than the Yellow River . This is the obvious difference between the rivers north and south of the Qinling Mountains.

The Qinling Mountains are not only the dividing line between the north and south climates, but also the transition zone between the Oriental and Palearctic in the world's animal geography, and the intersection of the north and south flora. The complex and varied, distinctive geological landforms and climate types have nurtured a rich variety of wild animal and plant resources, and the biodiversity is extremely rich, and it is known as the "biological gene bank."

Vegetation of Qinling Mountains.

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From the perspective of vegetation, the southern slope of the Qinling Mountains is based on deciduous broad-leaved and evergreen mixed forests, with evergreen, deciduous broad-leaved mixed forests, deciduous broad-leaved forests, coniferous broad-leaved mixed forests and coniferous forests from bottom to top.

The southern slope is a subtropical forest vegetation landscape below 800 meters above sea level; the northern slope is affected by altitude, climate, soil and other comprehensive factors, and the vegetation landscape has a distinct vertical distribution, with deciduous oak forest belt, birch forest belt, coniferous forest belt and alpine shrub meadow belt from bottom to top, forming a typical warm temperate mountain forest vegetation landscape. Therefore, the Qinling Mountains are the dividing line between the warm temperate zone and the northern subtropical zone.

The vast Qinling Mountains run across Shaanxi from east to west, forming a dividing line between the north and south climate, soil, vegetation, and animals. The animals and plants in the north and south have become exhausted, but some animals and plants can still continue to extend to a certain extent to the south and north, making the Qinling Mountains a gathering place for various flora and fauna and showing a certain transitionality.

Clouds over the Qinling Mountains.

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The Qinling Mountains not only stretch across the north and south in a geographical sense, but also erect a high wall in people's hearts.

When Han Yu was demoted, he passed through the Qinling Mountains and sighed in front of the vast mountains: "Where is my home with clouds across the Qinling Mountains, and the horses cannot move forward with snow blocking the Lan Pass." When Bai Juyi was demoted to Jiangzhou, he wrote a poem to his good friend Yuan Zhen, and he could not hide his melancholy about the bleakness of the Qinling Mountains: "Spring snow on the Lan Bridge when you return, autumn wind on the Qinling Mountains when I leave." It can be seen that in the minds of ancient literati, the Qinling Mountains marked the division between the prosperous imperial capital and the desolate place of exile.

Although the Huai River does not erect an insurmountable barrier like the Qinling Mountains, if you broaden your horizons, you can also see the differences between the two sides of the river. It is not as meritorious as the Qinling Mountains on the north-south dividing line, but more like a lucky person, born at the edge of a natural zone.

Huaihe River Highway Bridge on Jiefang Road in Bengbu City, Anhui Province.

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The Huaihe River is an isotherm with an average temperature of 0 degrees Celsius in January. Rivers and lakes to the north of the Huaihe River may freeze, but those to the south will not. In the north-south division of the rain belt, the Huaihe River is also the dividing line between the spring rain and summer drought type and the spring drought and summer rain type.

In terms of vegetation, the Huai River is also the dividing line between evergreen and deciduous broad-leaved forests. However, these lines are not precisely coincident, but are scattered over an area of ​​dozens or even hundreds of kilometers north and south of the Huai River.

Sea of ​​clouds at sunset in Qinling Mountains.

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In fact, as long as we do not stick to one "line" and instead treat the Qinling Mountains and the Huai River as a wider buffer zone, the problem of the north-south dividing line will be easily solved.

In addition, the global climate has changed significantly in recent decades, which has also led to the shift of some contour lines. When meteorological statistics were collected at the beginning of the liberation, the 0℃ isotherm in January was indeed basically coincident with the Qinling Mountains and the Huaihe River. Now that the climate is warming, the 0℃ isotherm in January has obviously shifted northward. Perhaps, in a few years, the "north-south" division will move to a position that we can hardly imagine now.

Article丨West Lake Vinegar Fish

Part of the content is from | "Qinling Natural Observation Manual"

References:

[1] Qinling Natural Observation Manual

[2] The dividing line between the north and south of the Huai River, the fighting arena of heroes

[3] The Fog on the North-South Dividing Line

Source: China National Geographic BOOK

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