If we are to understand the economy of the land use of New England, we are going to need to know much about the land of New England itself and its infinite variations. Land, generally speaking, is the surface of the earth, its components of soil, subsoil, and parent rock, and associated topography, climate, rainfall, and sunshine. In this chapter, we will deal particularly with the soil aspect of land.
By the term soil, the scientist refers only to the thin upper layer of the earth surface in which the living roots of ordinary plants and trees are found and in which organic materials are being constantly fused with mineral in the soil-building processes. The nature of these physical, chemical, and biological processes is determined by temperature, rainfall, topography and drainage, and the type of plant growth resulting. One must never forget that the soil is in large part a product of climate and topography. But the final soil product also depends upon the kind of mineral parent material beneath the soil, whether it is weathered from sandstone, shale, or limestone, to choose from the sedimentary rocks; or from granite, trap, gneiss, or schist, to choose from the igneous and metamorphic group. It also depends upon the texture and arrangement of this parent material, whether, to mention extremes, it is in the form of a loose assortment of coarse fragments, or of compacted fine-layered materials that are more or less impervious. Beneath the parent material, ordinarily at depths from 3 to 25 feet, is the bedrock, commonly very much like the parent material except that it is unweathered and unbroken. There are numerous locations, of course, in which glacial action, or stream or wind deposition, have laid down upon the bedrock a type of material very different from it, transported here from some other geological formation.
How to use soils information in studies of land use has long perplexed