The history of Tang Laiqu

By the Tang Dynasty, all the old canals in the Han Dynasty had been renovated, newly built and expanded. The famous canals are Hanqu, Qiji, Guanglu, Shangshu, Shi Yu, Bo Gu, Huqu, Baijia and Tejin.

The large-scale development of Tanglaiqu irrigation area moved Huaiyuan County (now Yinchuan) from the west terrace of the Yellow River to the bank of Tanglaiqu in the middle terrace, which marked the development of the irrigation area to the middle plain with low-lying, dense lakes and marshes and original salinization of soil, and marked the improvement of productivity level in Tang Dynasty to a new stage.

According to official records, Yinchuan Plain was rich in rice in Song Dynasty.

The author believes that at the latest in the Tang Dynasty, a large area of rice cultivation should have been developed here [8].

Because the main part of Tanglaiqu irrigation area is a heavily swamped area in the middle of the plain, people have to use the method of ditching and draining, planting rice and washing salt to transform it (this method has been adopted in many areas of the Yellow River Basin as early as the end of Han Dynasty).

The agricultural proverb of "planting rice in furrows and furrows will bring benefits to saline-alkali land" handed down from generation to generation by farmers in Yinchuan Plain is a summary of the production experience of past dynasties.

It is said that Guo cultivated land in the west of the river, made full use of land and water, and achieved a bumper harvest of rice.

When Xuanzong was in Xuanzong, he was stationed in Lingzhou, so he must pay attention to promoting rice cultivation.

It goes without saying that since then, some lakes and swamps in Yinchuan Plain have gradually turned into rice fields with human intervention.

With the expansion of paddy fields and the increase of water transfer, the surplus irrigation water may converge to some new lakes and swamps downstream.

After the Ming and Qing Dynasties, the irrigation area of the plain was expanded on a large scale, especially during the Kang Yong period in the early Qing Dynasty, canals such as Daqing, Huinong and Changrun were newly built. The irrigation area jumped from the original 6.5438+0.7 million mu to 2.4 million mu, but the drainage facilities were not built accordingly, and the problem of uneven drainage and irrigation suddenly became very prominent, resulting in a large number of depressions between canals and lakes.

In the irrigation area of Yinchuan Plain, under the condition of water diversion without dam in ancient times, a number of canal systems were gradually formed, and the main canal was arranged in parallel with the Yellow River, which divided the irrigation area into north and south strips, resulting in the opening of bucket canal and agricultural canal directly from the main canal, which often caused breaches in irrigation.

In Yinchuan area, due to the river barrier, except for Huinong Canal in the easternmost part, other main canals can't retreat safely. When the river rises or rains, the canal water can only be discharged into the lake ditch, which has caused chaos, stagnant water and dense lakes and marshes in the middle and lower reaches of Yinchuan Plain in history.

Generally speaking, the coastal areas of the Straits are high-lying agricultural areas. Obviously, the high terrain on both sides of the channel is caused by sediment deposition caused by irrigation and channel breach year by year. Between the two canals is a lake depression zone, which appears regularly from west to east.

This kind of lake is a secondary lake formed with the development of irrigation area. It began in the Han and Tang Dynasties and reached its peak after the early Qing Dynasty. It can be called inter-canal depression lake.

During the Qianlong period of the Qing Dynasty, there were 48 famous great lakes near Fucheng (now Yinchuan) in Ningxia, including Changhu Lake and Yuehu Lake, and 72 rivers.

"Lotus Lake Fishing Song" was one of the "Eight Scenes of Shuofang" at that time. It is said that "on the east bank of the pond canal, there are many lakes that store water, which is called Lotus Lake by custom, also known as Lotus Lake.

Between Shaogang and Li Jun, this fortress is the largest, with dozens of miles around. There are many fish in the water, which are clear and green. The mountains are reflected and the trees are far away. There are canoes in the smoke from time to time, and people passing by are thinking of moving to the countryside. "

In feudal society, when water conservancy was not repaired, in case of rainstorm and flash floods, the Yellow River flooded or burst, it was often "the water flowed across the river, soaking in Long Mu, and there were no seedlings in the wild", and lakes, swamps and fields merged into Wang Yang.

It can be seen from 1935' s Survey of Canal Water Flow in Ningxia Province and Tanglaiqu River Area Map that almost all branch canals are lakes and swamps.

The water area near Yinchuan actually accounts for about 1/4 of the total area.

Hedong Han canal "all tributaries have nowhere to discharge excess water, which is collected in the downstream area between Qin and Han canals, forming a lake-beach connection, which is endless." There are more than 20 famous great lakes and beaches, of which Balang Lake is the largest, Fiona Fang 10 km, and Fiona Fang is the smallest one or two kilometers.

The result is that the inter-canal zone is generally swamped and salinized, which affects the stable and high yield of agriculture.

Therefore, although the central area of Yinchuan Plain developed in the Tang Dynasty, the average grain output remained at the level of tens of kilograms for a long time.

In the low-lying areas of Yinchuan Plain, there are also waterlogged depressions and lakes and marshes formed after the earthquake. The most prominent examples are Mancheng and Baofeng in Ningxia.

Ningxia Mancheng is a castle built in the first year of Yongzheng in the early Qing Dynasty (1723), where Manchu flag soldiers were stationed. It is located 2.5 kilometers outside Manchuria, the capital of Ningxia.

Its city is low-lying, and the water is muddy every rainy season.

After the earthquake in the third year of Qianlong (1739), houses collapsed, the city walls were sunken, and the terrain was even more sunken, forming a waterlogged swamp, which could not be rebuilt. Therefore, the city had to be moved to 7.5 kilometers west of Fucheng (now Yinchuan New Town).

The former site of the city (now located in Man Chun Town, a suburb of Yinchuan) has become a fish pond and a rice field.

Baofeng County, which was newly established during the Yongzheng period, was also devastated by the earthquake and the ground subsided. "After the earthquake, a big hole was opened, the water spun out and the river flooded into the city. A piece of Wang Yang, as deep as four or five feet to six or seven feet, froze many people and livestock, and all weapons and other items were flooded. "

Since then, Baofeng County has been revoked. During the annual inspection of Baofeng City (where Baofeng Township in Pingluo County is located)198/kloc-0, there were still large lakes and marshes inside and outside, and residents only lived in the corner of Cheng Nan.

In addition to freshwater lakes, Yinchuan Plain has primary and secondary salt ponds since ancient times.

According to reports, Huaiyuan County (Huaiyuan County and huaiyuan town in Yinchuan during the Tang and Song Dynasties) "has three salt ponds ... the red peach salt pond is like a peach blossom, and the county is 320 miles west; Wuping Yanchi is twelve miles northwest of the county, and Hechi Yanchi is one hundred and forty-five miles northeast of the county. " Among them, Wuping Yanchi must be in Yinchuan Plain.

By the Ming Dynasty, there was Yanchi15km in the north and south of Fucheng, Ningxia. The output is not much, and officials can't help it. It is estimated that this is a mixture of chloride and sulfate.

Until the founding of New China, nitrate was still collected near the North Tower of Yinchuan City.

As we all know, all lakes and marshes in Yinchuan Plain that are not directly connected with rivers and canals are salinized to varying degrees, becoming bitter salt lakes, salt lakes and even salt lakes.

After the founding of New China, a relatively complete drainage system was built, and many shallow lakes and waterlogged depressions were drained. The area of the lake has decreased from about 790,000 mu before to about 240,000 mu in 1958, leaving only 1600 mu.

The water depth of existing lakes has also been greatly reduced.

In addition, the area of seasonal waterlogging depression has decreased compared with the past, and the geographical landscape of Yinchuan Plain has undergone tremendous changes.

The complex process of shrinking-expanding-shrinking experienced by plain lakes and swamps in geological period and human history period is influenced by many natural factors such as land subsidence, sediment deposition, flooding of the Yellow River and dry climate.

However, since the development of the Yellow River Diversion Irrigation Area in Han Dynasty, the changes of lakes and marshes are mainly related to the development activities in different stages of the irrigation area, and various natural factors are relatively secondary.

The change of lake and marsh area, especially the change between canals, and the salinization or desalination of water body can basically reflect the balance of irrigation and drainage and the balance of water and salt in different periods of irrigation area.