中国土壤科学发展的理论与实践（Theory and practice of soil science development in China）Theory and practice of soil science development in ChinaZhao Qiguo 1, Wan Hongyou 21: Nanjing Institute of soil science, Chinese Academy of Sciences, Jiangsu 210008, China; 2: Department of urban and resource science, Nanjing University, Jiangsu, Nanjing 210093, Nanjing, ChinaAbstract: from the angle of the soil as a common carrier of resources and environment, expounds the characteristics and direction characteristics, development of soil science of soil science research, put forward the soil 3P, 3S soil and soil 3R future research content innovation. It is believed that the theoretical foundation of modern soil science development should be firmly grasped, and the modern soil science should be enriched and developed, and the practical application of soil science development and innovation will be further promoted.Key words: soil science; soil circle; development and innovation; theoretical basis; practical applicationCLC number: S15, document identification code: A, article number: 1672-2175 (2004) 01-0001-05Soil is an important natural resource for human survival and development, and it is also one of the important environmental factors. Therefore, with the increasingly prominent problems of resources and environment, soil science is bound to face new challenges and developments. In order to enrich and develop modern soil science, it is necessary to constantly develop the theory and practice of soil science and make it constantly innovated.1 development of Soil Science1.1, the characteristics of soil science developmentThe development of Soil Science in twenty-first Century will have the following 5 characteristics. (1) the research field has been developing to a deeper level, and the branches of disciplines have been continuously expanded. The comprehensive study of soil properties and processes has been made from different angles, so that soil science has made significant progress in depth. (2) the scope of research will be further developed in terms of scope. Soil research will be more interdisciplinary and comprehensive, and will pay more attention to the effects of soil and environment, soil quality, soil fertility, ecology and health in solving the major problems in the national economy. (3) the quantification and informatization of soil science research will be developed day by day. Regardless of the soil properties, soil processes or soil classification research, will continue to tend to quantify and information. (4) long-term observation and study of soil dynamics and location will be an important indicator for systematic study of Soil Science in the future. Because of the complexity and variability of soil itself, it is only through long-term observation that the dynamic characteristics of soil properties can be understood. (5) soil research will become more and more internationalized. Soil research is not only related to a country or region, but more to the international community. International cooperation and exchanges will be strengthened, 1.1.2 the characteristics, development and research directions of Soil Science ResearchTwo characteristics of 1.2.1 Soil ScienceThe characteristics of soil science are determined by the soil itself. In the course of its development, it has its own distinctive characteristics, that is, temporal and spatial difference and relative stability.Temporal and spatial differences of soil as an independent body in the occurrence and development of natural history, both in time and space is changing, this change due to the environment and human impact of external conditions such as different or change showed inconsistency, namely the difference. At the same time, the occurrence and development process of the soil itself is slow, has its own law of development, not because of external conditions and mutation mutation, but in its occurrence and development process in accordance with the external conditions change change. Stability is relative, occurrence and development are absolute. It is through the constant exchange of material and energy with the outside soil that it can happen and develop, which also makes soil management, improvement and restoration possible.The spatial and temporal differences include regional, diversity, variability and restriction. It is precisely because of the existence of time and space differences that the soil between different regions presents diversity and variability, and has regional distribution. However, this diversity and variability are constrained by the laws of soil development and development, as well as external conditions. This makes the soil distribution have a certain regularity.Relative stability includes experience, accumulation, gradualness and permeability.Chinas soil science development from 1930 survey of the former Central Geological Institute of soil chamber have been es