"People do not eat unless they are in the valley, and the valley does not grow unless it is in the land" comes from Guanzi · Eight Views. The original text is: "The people do not eat without grain, do not grow without grain and land, do not move without land, and do not work with people, so as not to bring wealth." It means that the people do not eat without grain, and there is no place for grain to grow without land. This reflects the idea of "food is the most important thing for the people" and emphasizes the irreplaceable role of land in agricultural production. In the White Tiger Tongyi compiled by Ban Gu in the Eastern Han Dynasty, it was said that "people cannot stand without soil, nor can they eat without grain", which also emphasized the importance of food and land for the people and the country. This is also the inheritance of the above ideas in Guanzi that was first seen in ancient books. Wang Fu's "On Hidden Husband - Real Border" also said: "Those who live in the land are the foundation of the people. Honesty cannot be left uncultivated for a long time." It also reflects the important position of land as the foundation of agriculture and the root of farmers. It can be seen that land is the most valuable resource for a nation and a country to survive, and is the cornerstone of productivity development, social prosperity and stability, and people's living and working in peace and contentment. The Chinese nation has always attached great importance to agricultural production and achieved a brilliant farming civilization; As the most important means of production in agriculture, the understanding and protection of land became the top priority of the ancients. As early as the Spring and Autumn Period and the Warring States Period, the people's exploration of the nature of land has been very advanced. Yu Gong, written about in the Warring States Period, recorded the land characteristics and output of Jiuzhou. According to the fertility level, the soil in Jiuzhou can be divided into three grades and 18 types, 90 kinds in total. There are many proper nouns in Shuowenjiezi: "soil" refers to soft soil, "lu" refers to hard soil, "yang" refers to red hard soil, "gui" and "gui" refers to hard soil, "kai" refers to high and dry land, and "yu" and "jin" refers to clay, which shows how meticulous the working people's understanding of land in ancient times has been. The agricultural books of previous dynasties also took soil conservation and fertility conservation as important discussion contents. In Wang Chong's book "On Balance and frankness" in the Eastern Han Dynasty, "a man is fertile and has the nature of the land. A fertile man is beautiful in nature, and a fertile man has luxuriant crops. A fertile man is evil in nature. He plows deeply and hoes carefully, adds thick manure soil, and encourages people to work hard to help the land. His crops are similar to those of other fertile men." It can be seen that the ancient people had realized the importance of how to increase the fertility of the land and maintain the "land" two thousand years ago. All things grow in the soil, and cultivated land is the essence of land resources. China is a country with a large population and a large demand for food. The conservation, protection and rational allocation of cultivated land resources are crucial. In addition, cultivated land also has a strong ecological protection function and is an important part of ecological civilization construction. Therefore, the value of cultivated land must not be measured by the cost price in the sense of ordinary economics, and its fundamental, scarce and strategic value must be fully recognized. The 18th National Congress of the Communist Party of China