The study of the soil in the field comprises the detailed and accurate observation of certain natural phenomena, including not only the growth and development of surface material but the soil as a whole in relation to the various forms of life with which it is associated. The study in the laboratory of the material obtained by the sampling of a soil pit is an essential adjunct to soil study, but it is not the study of the "living soil". So soon as a soil sample is removed from its environment it "dies", and though laboratory investigation is necessary in order to obtain information not otherwise available it is essentially of the nature of a post-mortem examination. Soil scientists are now beginning to realize that the story of a soil is told by an examination of it in its natural environment. The observation of the land worker have been used by him in the utilization of the soil from the earliest ages, but these very observations which have meant so much to him have too frequently been neglected or discounted by the laboratory investigators of the last half-century. The idea that a simple chemical analysis of a "dead" soil sample taken in any arbitrary manner would solve the problems of economical fertilizing and cultivation is now fornunately nearly extinct. In its place is growing the conception of the soil as a live substance, almost an entity. A soil grows, develops, and responds to environment, care, and sympathetic treatment much as a true organism does, and history is full of examples of man and soil working together towards their mutual evolution and, in fact, the farther one goes back into the history of the agricultural utilization of land the more one is led to believe in this define but indefinable property special characteristics by means of which it can be recognized and, in consequence, ultimately classified. The term now generally adopted to describe the "form" of the soil is "soil profile". The soil profile is the manifestation of all the changes, growth, and development which have taken place during the "life" of the soil, and it may be studied by any intelligent observer when he works on the land or digs a hole in the earth. The pedologist must be a naturalist in sympathy with his subject, must know what to look for, and how to interpret the true significance of his observations and utilize them for the advancement of his study. The necessity for systematic study of the soil profile, both in relation to its environment in the field and its behaviour in the laboratory, becomes evident after the consideration of a few points. Since, until a subject of study is classified, knowledge of that subject is incomplete, it is obvious that the first and fundamental duty of pedologists is the classification of soils. Many efforts have been made to standardize a system of soil classification, nearly all of the more recent of which have been tolerably successful in the countries of their origin, and soil utilization schemes and maps have resulted. They all differ, however, in their systematism and nomenclature one from another, but they all recognize the necessity for the profile pit as the picture of the life-history of the soil. For the rational utilization of land, to which end all pedological researches should ultimately be directed, a soil-profile, survey is essential. A good soil description on the "site and profile" principle should be so complete that no further inforation is required to arrive at a technically perfect system of rational utilization. The ideal for which the pedologist must strive is the accumulation of knowledge for the ultimate utilization of land, and no system of soil study has yet been evolved which can supply this knowledge better than the study of the soil profile in relation to its environment, first in the field and then in the laboratory. In the soil environment must be included the natural or cultivated vegetation since, until the weathering complex of the mineral material has borne vegetation and obtained its complement of humus and become "live", the material is not soil. The term "humus" in the foregoing sentence includes not only the products of the decomposition of vegetable matter but also the living organisms which bring about the biochemical reactions of this decomposition. Newly weathered rocks, desert sands, or sea sands, until anchored by vegetation and humus, cannot be soils or develop into soils. Vegetation and soil development cannot be dissociated, since it is impossible to see or to find out where, in the soil proper, vegetation ceases and the ultimate mineral particles of the soil begin - they are, in fact, completely merged into a natural living unit.
