(3) Benefit from pond salt

Yuncheng salt lake

Yuncheng Salt Lake is the only inland salt lake in the Central Plains. Shanxi people benefited from salt making as early as four or five thousand years ago. The earliest record of salt industry is the post of "salt man" in the series of officials in the Western Zhou Dynasty. He was the first official in charge of salt affairs. He supplied salt to the current dynasty for different purposes, some as sacrificial salt, and the quality of salt enjoyed by officials of different grades was also different.

There were salt officials in the Zhou Dynasty, which shows that salt should have been in circulation before the state set up officials. Early people did not produce salt, but only collected natural crystalline salt from salt lakes to eat. Later, the supply of salt increased, and more people used salt, and the salt dispersed. Salt was the best condiment at that time. When our distant ancestors tasted salty for the first time, what a pleasant surprise it would be. It should be accidental. This kind of accident may have two sources: first, the ancients mistook the lake for fresh water, tried to quench their thirst but drank it by mistake, and then abandoned it after it was bitter and salty, but in the end, the ancients thought it was salty and delicious, so they spilled food on the lake and ate it. In the second way, the prey died in the lake, or accidentally dropped the food into the lake. The ancients also tasted salt. This is the first stage of using salt. Later, the ancients found that the small white crystal near the lake was salty and could also be used for seasoning. It could be carried around, transported in large quantities and exchanged goods. This is the second stage of using salt. The third stage is the sharp increase in salt consumption, and the salt-using areas are expanded to different nationalities and clans hundreds or even thousands of miles away. After that, the crystallization of natural salt can't keep up with people's needs, and we will think of ways to build beds to dry salt. This is also an artificial salt-making method adopted by the ancients for long-term observation of the changing law of natural conditions of salt crystallization.

Some historians speculate that the first gathering place of China ancestors was within a few hundred kilometers of Fiona Fang, not far from the salt lake, which may be related to the salt produced in the salt lake.

The chemical composition of salt is sodium and chlorine, both of which are essential elements for human body. Each adult contains sodium 105g and chlorine10.5g.. The necessity of human physiology is the primary reason why people like salt, followed by delicious condiments. Today, people raise cows, sheep, horses and donkeys and often feed them with salt. When they can't eat salt, they will lick the nitrate soil in the corner, which is also the physiological instinct of animals.

How is the salt produced in the salt lake? The principle is simple. When the evaporation of inland lakes is greater than the precipitation, the salt molecules in the water are continuously concentrated, and the fresh water in the lake is transformed into salt water, salt water and brine. When the salt content reaches a certain concentration and the water evaporates, the salt will crystallize out. The annual precipitation in Yuncheng Salt Lake is 400 ~ 600 mm, but the annual evaporation is as high as 2200 ~ 2900 mm. Without groundwater recharge, the water in the salt lake will be evaporated in a few months.

Yuncheng Salt Lake covers an area of 130 square kilometers, and the water-receiving area of the lake defined by Mingtiaogang Uplift is 235 square kilometers, that is, the salt lake has only a small surface water supply less than twice the lake area, so it is difficult to form such a rich salt source with such a small water-receiving area.

The Sushui River basin covers an area of 5,774 square kilometers. Except for the lower end of the basin, most of the groundwater is replenished to the salt lake, which is lower than the place where the Sushui River enters the Yellow River, so the groundwater receiving area of the salt lake can reach 4300 square kilometers. Groundwater ensures that the source of salt will never be exhausted.

By radioisotope determination, the earliest age of carbon in sapropelic mud under salt plate layer left by people mining salt at the bottom of lake is 4653 87 years. This proves that the era of large-scale artificial salt mining should begin in the Xia Dynasty (2070 BC, 4080 years ago). According to historical records, the original salt mining method was to salvage the salt naturally deposited at the bottom of the pool. But the speed of natural deposition can't keep up with the amount people need. It was not until the Tang Dynasty that the method of "watering while ploughing" was invented, that is, embankment was built around the flat land by the lake, and the high-concentration salt water in the lake was sucked up by artificial pumping, and it was dried by the sun to obtain salt. This method can extract a foot deep brine and harvest a batch of salt in 5 ~ 6 days. Since the invention of this method in Tang Dynasty, the area of artificial salt field has been expanding day by day, and the annual output has been rising. By the Song Dynasty, the annual output of salt had reached 36,000 tons, and the daily average salt was 100 tons (654,380+100000 kg), which showed the high output. The highest annual salt production in history can reach 6.5438+0.44 million tons.

The salt lake gathers all the salt in most groundwater in Yuncheng basin, which ensures the salt demand of the people in the Central Plains. The eastern region relies on sea salt, the western region relies on well salt and pond salt, and the Central Plains region mainly relies on salt from Yuncheng Salt Lake.

The State of Jin rose in the Spring and Autumn Period and became a tyrant in the Central Plains. The profit of salt lake is an important factor. Similarly, the rise of Chu in the south is also related to the profits of oriental sea salt. At first, salt ponds were open for people to fish. In the Spring and Autumn Period, Guan Zhong proposed to levy taxes from people's interests, and salt tax became an important economic income of the national treasury. In the prosperous Tang Dynasty, the tax revenue of Yuncheng Pool can reach a quarter of the total national tax revenue. It can be seen that Yuncheng salt tax is important to the country. China's famous Guan Gong was born in Xiezhou, near Yanchi. At first, he also made a living by smuggling salt (avoiding the guards of officers and soldiers and smuggling salt for export). Later, because of resisting oppression, he killed talents, fled to rivers and lakes, and became sworn in Taoyuan.

People thank God for giving great benefits to Yanchi, which is why Yanchi Temple was built beside the pond to worship Salt god, a salt minister in the era of the Yellow Emperor. At the same time, he worships the sun god, who is the founding father of drying salt; It is also dedicated to Fengshen, because the temperature is low in winter, and a pool of salt water can only be done in twenty or thirty days. In early summer, when the south wind comes and the weather is warm, the salt output can go up quickly, and you can get a pool of salt in 5 ~ 6 days. In addition, under the caress of the south wind, the wind will stir the salt in the pool water evenly, making the salt crystallization more smooth. In winter, the strong wind is too strong, and silt and bitter brine rich in magnesium sulfate appear at the bottom of the pool, which reduces the quality of salt. Therefore, only when the south wind blows gently will it be beneficial to the salt industry. Legend has it that Shun Di sat on the Yungang in the north of the pool, stroking the banjo and singing "Song of the South Wind": "The south wind can relieve the anxiety of our people; When the south wind blows, it can enrich the people. " "Sorrow" means sadness and pain. When the south wind comes, people's lives will begin to get out of sadness. "Fu" means wealth. When the south wind blows at the right time, it can enrich everyone's wealth. This is the embodiment of Shun Di's thought of being close to the people and loving the people.

2. Pool salt promotes chemical industry

According to the composition of brine, metal ions are mainly calcium, magnesium, sodium and potassium; Anions are mainly carbonate, sulfate and hydrochloride. With the increase of pool water concentration, dolomite crystallizes first, then gypsum, then salt, then mirabilite and finally trona.

In Yuncheng Salt Lake, besides a lot of salt, there are many gypsum and mirabilite deposits. Glauber's salt is an important chemical raw material, which is the main raw material for preparing sodium sulfate, ammonium sulfate, alkali sulfide and sulfuric acid. It is used in glass, salt making, paper making, man-made fiber, dyes and pharmaceutical metallurgy departments. Before the founding of New China, private enterprises tried to develop and extract mirabilite from salt ponds, but failed for various reasons. After the founding of New China, a chemical plant was formally established to produce mirabilite, sodium sulfate (the trade name after mirabilite dehydration), alkali sulfide, bromine and other products. Before the 1970s, it was mainly salt, but it was flat in the 1970s. After 1970s, the chemical output value of salt such as mirabilite and sodium sulfate surpassed that of salt and became the main products of salt lakes. By the beginning of this century, as an export commodity in China, the output of sodium sulfate in Yuncheng Salt Lake accounted for 70% of the total export volume in China. Nanfeng Group, a leading salt chemical enterprise in Yuncheng, expanded its business to Europe, established chemical plants in Europe and developed salt ponds in Western Europe.

Hedong county is rich in salt, which is not only the main product of salt, but also drives the transportation industry. In order to transport salt to the vast areas of the Central Plains, professional transport teams are needed. Therefore, since the Sui Dynasty, the Yaoxian Canal was built in the parallel salt pond on the north side of Mingtiaogang. One is to drain and protect the salt pond, and the other is to expand the transportation capacity by replacing manpower with ships. Finally, the small town centered on salt transportation was expanded to Yuncheng, and the original Anyi and Jiezhou county-level units were swallowed up to build Yuncheng County until Yuncheng City.

Bole saw Maxima once transported salt in the south of Yanchi, so he rescued Maxima. This is the story of "Bole Xiang Ma".