1. Geology pioneered soil research

Humans interact with soil through cultivated rice. As mentioned above, the earliest development was in the Paleolithic Age in Hunan, about 14,000 years ago. The transition period to the Neolithic Age; the earliest written records about soil in my country were in the Xia Dynasty during the Xia, Shang and Zhou dynasties, about 4,000 years ago; but the inclusion of it into the scope of modern natural sciences to study soil began in geology. There is no independent soil science.

Foreign geologists Faro, Richthofen, Raman and others studied soil from a geological perspective and believed that soil is a loose layer on the surface formed by the weathering of rocks, that is, the product of rock weathering. Fiske, a German scientist who specialized in studying soil at that time, said, "Soil was a rock at some time in the past, and now it is forming a rock. From a petrological point of view, soil science can be regarded as a rock with an independent soil structure. "[1]. Since geologists studied soil from a geological point of view during this period, it was called the "agricultural geology school" in the history of soil science research. At the same time, soil research institutions were also located within geological research institutions, such as in 1907 The Institute of Geology of the Royal Hungarian Academy of Sciences established the world's first "Agricultural Geology Department" to engage in agricultural geological research. The department's main tasks are soil geological survey, soil formation and classification [2].

Domestic research on soil is first and foremost geological. Richhoff, one of the founders of soil research from a geological perspective, visited my country seven times from 1868 to 1872. He visited Shandong, Zhili, Sichuan, Central China, South China, and Northeast China, and his footprints covered most of China. The investigation was mainly based on geology. There is no doubt that his geological survey had a huge impact on the development of geology in our country. Naturally, his study of soil from a geological perspective will also have a profound impact on our country. In July 1930, the then China Education and Culture Foundation commissioned The Central Geological Survey is preparing to build a soil research laboratory (the predecessor of the current Nanjing Soil Research Institute of the Chinese Academy of Sciences). In 1932, at the invitation of my country, the United States sent James Thorp to China as chief technician of the Central Geological Survey. His main job was first to carry out field soil surveys closely related to geology. In 1937, Hunan Province conducted field soil surveys in the Hengshan and Xiangxiang areas. The first soil survey was carried out by central geologists. Therefore, the first batch of soil researchers in my country were geological science and technology personnel at that time.

2. The theory of soil-forming factors emphasizes biology as the dominant factor, but ignores geological (parent material) factors

Dokuchayev’s theory of soil-forming factors is his work in Russia It was created while doing soil survey work on the Great Plains. The Russian Great Plain stretches for nearly a thousand kilometers. Within this area, there is an increasing temperature gradient from north to south; there is an increasing gradient of temperature and annual precipitation from east to west. Related to this are differences in vegetation types, especially the change from grassland vegetation to forest vegetation. Regular changes in climate and vegetation leave their effects on relatively consistent parent material, producing distinct soil differences. In this way, Kuchayev proposed the zonal distribution law of soil. Later, Sibirtsev deepened the zonal distribution law of soil into soil zonal theory, that is, connecting certain soil types with certain climate vegetation or geographical areas. The theory of soil zonation has been widely spread and has had a great impact, promoting people to conduct in-depth research and understanding of the role of climate, biology and other zonal soil factors in soil formation. This point, especially in the concept of "unified soil formation process" proposed by Williams later, further emphasized the leading role of biological factors in soil formation. He believed that the development of organisms as the leading factors in soil formation will cause changes in soil properties. It is the bioaccumulation process that dominates the pedogenesis process. In this way, the dominant pedogenic factors in the theory of pedogenesis are determined by organisms, and organisms (vegetation) are controlled by climate and have zonal characteristics. In this way, the theory of pedogenic factors has the theory of "only zonality", which is ignored in the classification of soil occurrence. In addition to other factors, especially the role of soil-forming parent material and parent rock; what is more, under the one-sided academic thinking in my country in the 1950s, the view of soil formation from a geological point of view, that is, the parent material and parent rock is regarded as an important soil-forming factor. Criticize the opposite, so that no one in the field of soil science dares to care about the role of geological factors in soil formation. This has brought great adverse consequences to the research and development of soil science in my country. As Academician Li Lianjie pointed out in 1991, " To this day, soil science has been left with intractable sequelae. For a long time, soil science has not been able to get its due status in soil science, which has not only affected the development of soil science theory, but also delayed the cultivation of talents."[1 ].

3. Soil scientists’ opinions on strengthening the application of geology in soil science

With the development of soil science in modern times, some knowledgeable people in the field of soil science have reconsidered the application of geology in soil science. The meaning of soil science, of course, is not simply a return to the era of Faro and Richthofen. Moreover, as far as geology itself is concerned, its level is far from the same as it was at that time. Therefore, it is inevitable for scientific development to reconsider and recognize the geological significance of soil science. For example, Academician Li Lianjie of Beijing Agricultural University has an incisive discussion on this.

Academician Li Lianjie (photo 2-7) graduated from the School of Science of Yenching University in 1932 and received a doctorate in philosophy from the College of Agriculture at the University of Illinois in the United States in 1944. After returning to China, he served as a researcher at the Geological Survey of China (Central) and engaged in Soil research.

He is one of the main pioneers and founders of soil science in my country. For more than half a century, he has been engaged in field investigation, scientific research, and teaching. He has made outstanding achievements in soil taxonomy, soil geography, geomorphology, and Quaternary geology. In 1955, he was appointed as a member of the Chinese Academy of Sciences ( academician). Since the 1990s, he has repeatedly discussed the significance of geology in the development of soil science. For example, in the preface to the monograph "Soil Geology" [3] published by the Agricultural Press in 1992, he believed that "the continuous soil on the earth's surface "It is an undoubted and arduous task for geoscience in soil science to accurately identify and classify the soil." He also pointed out that neglecting geology "affects the development of soil science theory" in theory; in practice, "soil is divorced from the foundation of geoscience." It is also difficult for science to solve current practical problems. "In view of the current actual situation, he predicted that "it will not be too long before we start to use geoscience as an important basic theory of soil science."

Photo 2-7 Li Lianjie. Academician (1908～1992)

When the author introduced geological results into the field of agricultural research in 1987 and took the lead in carrying out agricultural geological research in Hunan, he attracted the attention of Hunan agriculturists, especially soil scientists. For example, Mr. Tang Xinnong, former soil science professor of Hunan Agricultural College, once pointed out that "Hunan agricultural geological research is an important basic research in agriculture, which is very meaningful and necessary for the development of soil science"; Hunan Academy of Agricultural Sciences Mr. Xiao Zehong, a well-known soil scientist, believes that "it is very meaningful to use geoscience results to conduct agricultural geological research to serve agriculture. Agricultural geology has a marginal scientific nature, and research must cooperate with the agricultural department."; Hunan Province Agricultural Economy and Agricultural Zoning Research Regarding the application of geological science to agricultural zoning, researcher Duan Zhengwu, the former director of the institute, believes that "the use of rich geological data for agricultural development and extension to agricultural zoning is a marginal cross-research. This is a better guide for deepening agricultural zoning research work." In terms of agricultural layout, it is of practical significance to implement agricultural zoning to promote agriculture through science and technology." Researcher Yin Jirong, former president of the Hunan Academy of Agricultural Sciences, believes that "the combination of agriculture and earth science is necessary, and this combination itself is an innovation."