One winter day, the craftsmen of the city were busy with surveying and planning.

Finally, before the beginning of spring, Su Bo presented the final method of supervision.

The warm breeze is coming. Nowadays, every family has a boiler greenhouse, and the total amount increases, and the heat loss is relatively reduced. Firewood within 100 miles, especially smokeless charcoal, is sold into Lousang. The villagers of Linxian County have benefited a lot.

Liu Bei will be fifteen during the New Year. Although he is only twenty years old, fifteen years old is already a sign of adulthood. Historically, his mother also let Liu Bei go out to study at this age. Bailu Zhi as a teacher. Now that I think about it, many old things are vivid, as if it were yesterday.

"Young owner?" Seeing that Liu Bei was silent for a long time, Su Bo asked out loud.

"Oh." Liu Bei came back to his senses, pointed to a ditch flowing through Li Ting in the picture, and said, "How come I don't know about this water? ”

Su Bo smiled: "The craftsman surveyed the terrain and found this deserted ditch upstream. It is the same as the ditch drowning in the water, which is dug by manpower. I asked the villagers of Liting to know that this canal existed in the Han Dynasty before the Han Dynasty, and it is unknown when it was excavated. One year later, the water was so heavy that it was silted up by mud and rocks, and now only the river is dry. After that, the giant horse water could only flow out of the Dukang ditch, and then it overflowed the river and flooded. ”

Liu Bei understood: "So, in the place of Dukang, there are actually two artificial canals. One name said: Li Tinggou. One name said: Governor Kanggou. ”

"Exactly." Su Bo pointed to the clear stream that flowed through Lousang and said, "The water in the Liting ditch was blocked, so it was diverted into a clear stream. ”

Artificial excavation of waterways, called ditches. Since it is called Liting Ditch, it is obviously also manually excavated. This ditch is also old, or it was also built by the Yan people during the Warring States period.

Liu Bei nodded: "So, you want to rebuild Liting Ditch." ”

"Yes, yes." This is exactly what Su Bo meant: "The reason why there is a lot of water is because there is a lot of water and there is little water to go." The water level continues to rise, breaking through the embankment and overflowing into a river. A few years ago, the young master ordered us to dredge the clear stream and speed up the upstream drainage. Now, a two-pronged approach is taken to reopen the Liting ditch and clean up the Dukang ditch, so that the upstream water can be divided into three channels and discharged three times. When the stagnant water flows out, the water surface of the water will be lowered. In this way, the embankment of the river and the polder will be built with half the effort. ”

Liu Bei nodded happily and asked: What is a polder?

'Polder', also called enclosure. It is farmland enclosed by embankments along rivers, seasides or lakeside areas. Build a fence around low-lying fields and store water outside the fence. There is a culvert gate on the embankment, which usually closes the gate to protect against water, and opens the gate to release water into the field during drought, so there is no worry about drought and flood.

Polders originated in the pre-Qin period.

It was developed from the 'encircling the silt lake as a field', and it was quite developed in the Tang Dynasty. The construction and maintenance of polders require a lot of manpower and material resources, which ordinary farmers cannot afford. Later generations of polders were very large-scale. During the Five Dynasties and Ten Kingdoms, the Southern Tang Dynasty and Wu Yue overhauled the polders in their respective territories, each polder with a radius of dozens of miles, like a big city. Among them, most of the low-sand polders with low terrain, poor drainage and heavy soil are planted with rice. High-sand polders, sorghum and wheat and other dryland crops are high-lying and well-drained, loose soil, and not suitable for maintaining water layers.

The earliest record of polders can be found in the "Lupi" in the Eastern Han Dynasty's "Yue Jue Shu Wu Di Biography".

It is also said that in the first year of Chiwu in Eastern Wu, Sun Quan was proclaimed emperor, and the general Ding Feng was the general of the five routes, guarding Wuhu and Xuancheng. He personally led the army and civilians to encircle the lake and build fields, and supervised the repair of the polder. Tens of thousands of people wore stars and moons, and after four years of hard work, they finally "surrounded the lake into fertile fields". Named: Qian Wei. Later, it was changed to Huimin Wei, and finally according to the appearance of the polder, it was officially named Jinbao Wei. More than 200,000 acres of Jinbaowei encircling the beach field of Qian Lake: "The embankment is one hundred and four miles long and forty-nine steps, the embankment (surface) is more than two zhang wide, the (embankment) is more than two zhang high, and the bottom is five zhang wide. The high places in the polder were built to defend the fields, and the ditches were dug in the low places, and the troops were stationed in the fields. They also relocated the displaced people, built houses, and built villages, so that the army and civilians could work in the meantime. ”

In the five dynasties, there was a polder in the south of the Yangtze River, a large polder, dozens of miles in square, like a big city, there were channels in it, and there were gates outside...... By the time of the Northern Song Dynasty, polders were further developed in the south. Wanchun Wei, Wuhu County, Taiping Prefecture, has 127,000 acres of land, and the avenue in the polder is 22 miles long. The polder can prevent drought and waterlogging, so it can always maintain a good harvest.

Song Yang Wanli's "Polder" has: "The surrounding polders are golden cities, and there is no distinction between the polders and the green at a glance." ".

The polders separate the farmland from the outside water, and regulate the inflow and outflow of internal and external water through the irrigation and drainage canal system and the manipulation of the sluices on the embankment. If there is difficulty in artesian irrigation and drainage, it is supplemented by water lifting machinery such as keel dumping to meet the water demand of farmland in the polder. In later generations, there will be polders around the riverside and lakeside lowlands, and there will be irrigation and drainage systems in the agricultural areas, the downstream will be called "wei", and the middle reaches will be called "wei", collectively referred to as "wei". A number of polders are connected together, which is called a polder area or polder area.

The 'cabinet field' recorded in the "Book of Agriculture" written by Wang Zhen in the Yuan Dynasty is a polder with a small area.

The plain area is dominated by polders, with beaches attached. The embankment is built around the polder, and the small polder outside the polder is the beach. The embankment along the half of the river and lake along the hill is called '埧', and the embankment at the exit of the hill and ravine and the place where there is no water is called 'cong'. Because Daxu 'square dozens of miles, like a big city', so the later generations of 埧, Cong mostly appear in the form of place names.

There are only 20,000 people in Lousangyi. To build a 'square for dozens of miles, like a big city', is not enough. The polder, Liu Bei is ready to build in batches. Divide the hundred miles of water into several areas. First take Lousang as the base and build a good governor. Gather the homeless, the craftsmen. When the governor Kangyi is full, then based on Lousang and Governor Kang Eryi, continue to Tuntian.

Similar to bee bins. One to two, two to four, four to eight, eight to sixteen. This is the most appropriate way to get twice the result with half the effort.

The direction of the ditch has been figured out by good craftsmen, and it is roughly a straight canal from north to south. Lead the giant horse water to the south, flow through Du Kang, and reunite with the north giant horse water into Laishui, rushing like the sea.

Just build an embankment along the west bank of the ditch to enclose the reclamation, there is a culvert gate at intervals on the embankment, close the gate to protect against water when it is waterlogged, open the gate to release water when it is dry, and ensure the harvest in drought and flood, it must be good land.

Unexpectedly, the people of Liting came to beg one after another, wanting to merge the land of Liting into the fiefdom.

Lousang Village is ten miles south of Zhuo County, and ten miles south is Liting. The people who live between the Li Pavilion and the Lucheng Pavilion have many fields between the two pavilions, and even belong to the Li Pavilion. The household registration moved into Lousang, and the land property naturally moved into Lousang. Now the Lousang paddy field is more than ten miles. Previously, the Lousang paddy fields were ripe, and the nearby villagers came to ask the old patriarch. I want to buy rice seeds, hire farmers, and change to paddy fields. The young prince asked the villagers of the nearby Tingyi to elect representatives to come to Lousang to learn art. The sectarians carefully taught rice farming.

Liting bore the brunt of the situation, and now all of them have been converted into paddy fields. However, the stream is small and the yield is not high. Dredging the Liting ditch can solve the dilemma of water shortage. The season is ripe, why not?

Su Bo said that if the people of Liting can be merged, there will be no constraints in dredging the Liting ditch.

Liu Bei took a picture to look at. It seems that the circle with a diameter of 100 miles can vaguely wrap the Li Pavilion in it.

Just waiting for the holy edict to be issued, how Liu Bei will divide and deliver with the state and county. A small pavilion shouldn't be a problem.

Rippling the Ground.

The word 'crack' is the essence of the word.