With the pencil this thing, the pen writing and painting is more convenient, the most important thing is to facilitate the draft, and the price is quite appropriate, and can be erased on the white paper, so, now Qujiang Academy and Weinan hope Yixue students are also each hand, of course, our Chinese national brush and calligraphy can not be lost.

For example, now, the pencil is sketching quickly in my hand, and it will not take a while. In front of the two princes, a map of the evolution of the Guanzhong area in later generations was eroded by flowing water, the valleys developed, and the long strips of land were divided. "This ...... Brother Jun, are you saying that in a hundred years, our fertile Guanzhong Plain will become like this? ”

"If we follow the unrestrained reclamation in previous years, our Guanzhong area of the Tang Dynasty will definitely change greatly, although my picture may be exaggerated, but it does not mean that it will not happen. And not only Guanzhong, but also the lower reaches of the river, after more than a hundred years, it has become a disaster......," I said in a deep voice. Yes, I came, I existed, I changed, I was able to do it, and I tried to do it, and as much as I could, fulfill the obligations and responsibilities of a traveler who knows the consequences of history from the future more than a thousand years from now.

"Could it be that Brother Jun, you have been asking for land exchange, moving the population of the densely populated area of Guanzhong to other regions as much as possible, and asking my father to prohibit the cultivation of fertile land in Guanzhong, all for the sake of this failure?" Li Zhi's expression also became solemn.

I didn't speak again this time, and by this time, all the officials who had been listening to it on the side had also crowded over and asked what was it that made us do this.

I can only tell the dozens of officials present what I understand about soil erosion, its formation and its harm.

The Guanzhong Plain of the Tang Dynasty is located on the Loess Plateau, the loess particles are fine, the texture is loose, the structure is loose and easy to be dissolved by flowing water, it is easy to be eroded and collapsed, which promotes soil erosion, the second is that since the Qin and Han dynasties, the population of the Guanzhong Plain has been growing rapidly, and the uncontrolled reclamation and grazing have destroyed the forest, destroyed the grassland, and the green vegetation has been seriously damaged, and the Loess Plateau has lost its natural protective layer, causing serious soil erosion.

------------------------------------------------ worse, soil erosion has significantly reduced soil fertility and resulted in a significant reduction in crop yields. The more production is reduced, the more people have to reclaim wasteland: the more land is cultivated, the more soil erosion will be. A cycle of bad names is formed. In addition, sparse vegetation and heavy rains in summer have contributed to the expansion of gullies and accelerated soil erosion. The erosion of the valley was intensified, and the valley slope continued to expand, so that the land between the ditches was broken. It is closely related to human activities, especially social factors such as indiscriminate reclamation and deforestation, and destruction of natural vegetation.

It's a pity that most of the dozens of officials and alternate officials in this group of offices here have half-believing expressions, can this son still use words to fool you? I was annoyed in my heart, but I remained silent on the surface: "This official also knows, just by talking about it, I am sure you will not believe it, although the data in my hand is evidence, but I can also find more evidence to prove that our Guanzhong Plain is in a dangerous period of instability." Fang Cheng! ”

In order to prove that everything we said was based on evidence, I immediately asked Fang Cheng to go to my home in Weinan to pick up the books I usually collected. Soon, Fang Cheng was holding a bunch of books.

I directly handed them to the officials in front of me one by one, and said with my usual memory: "Everyone, please see, this book "Yu Gong", "The Book of Mountains and Seas. The Book of the Northern Mountains and the Book of Han. It is recorded in the Geographical Chronicles that the lower reaches of the Yellow River flowed through the Hebei Plain and entered the sea on the west bank of the Bohai Bay. According to the literature, the Yellow River has changed back and forth many times...... Do you know why? It is because the sediment carried by the river has accumulated the original course of the river, so that the river has to wander and divert its course, or divert it in multiple streams. ”

I opened one book after another and turned to a place where it was clearly recorded, and handed it to every official around me, Cui Renshi, Wang Fangyi, and Di Renjie, and I kept expounding and describing everything I knew. These are all recorded in the book, we don't brag, and even the history books are there, which proves the accuracy of my words.

“…… From the end of the Western Han Dynasty, the river and river water in Jun County, Henan, were higher than the flat land, and it was obvious that it had become a 'hanging river'. This is the result of increased soil erosion in the middle reaches of the Yellow River since the Qin and Han dynasties. At the time of Wang Mang, the Yellow River broke east of Yuancheng in Wei County, and the river flooded to several counties east of Qinghe County. At that time, Wang Mang did not advocate blocking the mouth because the river broke to the east, so that his ancestral tomb in Yuancheng would not be threatened, and heard that the flood lasted for nearly 60 years, thus causing the second major diversion in the history of the Yellow River. ”

After the beginning of the Eastern Han Dynasty, a large number of nomads settled in the middle reaches of the Yellow River, returning farmland to grazing, secondary grasslands and shrubs replaced cultivated land, and soil erosion was relatively weakened. In the Eastern Han Dynasty, under the governance of Wang Jing, the overflowing river at the end of the Western Han Dynasty was comprehensively controlled, and a new river channel was fixed.

However, this does not mean that the river that nurtured the ancestors of the Chinese nation has been calm. More and more data show that soil erosion is still serious, although in recent years, due to the use of coal, the indiscriminate felling of trees in the Guanzhong area has been greatly reduced, coupled with the vigorous implementation of land replacement, so that in recent years, the population of Guanzhong Province has become a negative growth, that is, the population of Guanzhong Road has been decreasing in recent years, and the area of cultivated land is finally no longer expanding.

Cui Renshi made a face on the side, looking very serious: "What Master Fang said is not bad, Xia Guan is indeed in the "Hanshu. Geographical Chronicles have seen about the flooding of the great river during the reign of Emperor Wang Mangdi. ”

"This official is doing this in the hope that there will be a way to keep the prosperous land of our Datang and the fertile land of Guanzhong." I shook the form in my hand, very excited, yes, it's time to do it, otherwise, God knows that the Guanzhong Plain will not survive the war because of my arrival, but the problem is that the rapid growth of the population is also an important part of the environmental damage.

"It seems that this land replacement policy must be continued, and the population of Guanzhong really cannot be increased." Uncle Li looked at the large row of bottles in front of him, which were filled with sedimented water, Uncle Li could clearly see the reality, in addition, I also personally made a demonstration in front of Uncle Li, that is, to impact the loess dug from the outside with the water flow, and soon, the original hardened loess rushed out of the ravines in front of the rapid cement.

The loess clods overgrown with weeds on the surface are difficult to be washed away, this knowledge we can often see when we watch science and education films when we are children, but now, this son has to use this method to teach His Majesty the Emperor of the Tang Dynasty and the important ministers of the Tang Dynasty a vivid lesson on the principle of soil erosion and the mechanism of its occurrence.

------------------------------------------------Not only me, but also a large number of officials from the Ministry of Industry who are here to give a detailed explanation to these important ministers of the court who do not know anything about water conservancy.

After all, it is not a matter of one or two days for us to deal with the Ministry of Industry, and Yan Lide, who was originally the secretary of the Ministry of Industry, is also very familiar with me like his younger brother, and once he was drinking at his house, so he naturally talked about it. As a result, the argument began, Yan Lide, the elder brother, thought that this son was just doing something unfounded, while Yan Liben, a big country, remained neutral, and felt that what I said also made some sense, but the question was whether there was evidence? Although there are many records in ancient books, at this stage, the wind and rain in Guanzhong are very smooth, and there are no disasters and no disasters.

In the past, disasters occurred, it was just a consequence of the war, the country was not interested in civil affairs, and did not repair the water conservancy, and his words also had his truth, but this son is not so easy to convince the master, not to mention that we are from the next generation, so in the end, Yan Lide still agreed, seconded some water conservancy experts under the Ministry of Industry to the Jinju Academy, the research period lasted for several years, and now, the collected data has proved my correct surname and vision.

In the end, Uncle Li also agreed with the suggestion put forward by the Ministry of Industry, starting this year, the Guanzhong area will be prohibited from cultivating new acres of land, and in addition, the measures of returning farmland to forests and grasslands should be carried out in the areas along the river, and the efforts to publicize and promote land replacement will be intensified, so that the population distribution of Datang will be more even.

I am very glad that the political leaders of Datang unanimously passed this resolution, and Uncle Li is very happy to praise the work of the Ministry of Industry and the Jinjuanyuan, believing that the contribution of these two departments to Datang is absolutely unpredictable, and in doing so, it can also fundamentally solve the phenomenon of increasing disasters in the Guanzhong area, anyway, I always feel that the return of farmland to forests can be carried out more than a thousand years in advance, which is not only an increase in the environmental awareness of the Datang Empire, but also slows down the pace of decline of the fertile fields in Guanzhong.

(To be continued)