The newly issued classification guide adheres to the principle of scientific, concise and operable classification within the same level, adopts a three-level classification system, and * * * sets up 24 first-level categories such as cultivated land, garden land, woodland, grassland, wetland, residential land and industrial and mining land, 106 second-level categories and 39 third-level categories. Taking cultivated land as an example, the Classification Guide divides cultivated land in the first category into three secondary categories: paddy field, irrigated land and dry land, and explains the corresponding meanings and codes.
Land is a natural complex composed of rocks, minerals, soil, hydrology, atmosphere and vegetation within a certain height and depth of the terrestrial part of the earth. Geologists in China generally believe that land is a comprehensive concept of physical geography. Land "is a natural complex including geology, landform, climate, hydrology, soil, vegetation and other natural elements on a certain section of the surface".
Land, as a natural thing, has gradually transformed from the most basic ecological environment factor for human survival and development into human labor objects and labor materials, and is increasingly regarded as a treasure house of natural resources for human life and production activities, and has become the source and support of all production resources and production materials; And the land with natural resources and ecological environment elements will be transformed into artificial natural resources and artificial ecological environment elements into natural resources complex, so that the land not only has use value, but also has value (labor value).