Soil science is the study of soil as a natural resource on the surface of the earth including soil formation, classification and mapping; physical, chemical, biological, and fertility properties of soils; and these properties in relation to the use and management of soils.
Sometimes terms which refer to branches of soil science, such as pedology (formation, chemistry, morphology and classification of soil) and edaphology (influence of soil on organisms, especially plants), are used as if synonymous with soil science. The diversity of names associated with this discipline is related to the various associations concerned. Indeed, engineers, agronomists, chemists, geologists, physical geographers, ecologists, biologists, microbiologists, sylviculturists, sanitarians, archaeologists, and specialists in regional planning, all contribute to further knowledge of soils and the advancement of the soil sciences.
Soil biology is the study of microbial and faunal activity and ecology in soil. Soil life, soil biota, soil fauna, or edaphon is a collective term that encompasses all the organisms that spend a significant portion of their life cycle within a soil profile, or at the soil-litter interface. These organisms include earthworms, nematodes, protozoa, fungi, bacteria and different arthropods. Soil biology plays a vital role in determining many soil characteristics yet, being a relatively new science, much remains unknown about soil biology and about how the nature of soil is affected.
Invasive species of earthworms, specifically from the suborder Lumbricina, have been noted to migrate and spread through North America. Their introduction is having drastic effects on the multiple nutrient cycles in temperate or temperate-coniferous forests. These earthworms increase the cycling and leaching of nutrients by breaking up decaying organic matter and spreading it into the soil. Since these northern forests rely on thick layers of decaying organic matter for growth and nutrition, they are diminishing in diversity and young plants struggle in these environments. Many species of trees and other plants may be incapable of surviving such drastic changes in available nutrients. This change in the plant diversity directly affects the other organisms of the environment and often leads to increased invasions of other exotic species as well as overall temperate forest decline.
Lumbricus terrestris is a large, reddish worm species native to Europe]citation needed[, but now also widely distributed elsewhere around the world (along with several other lumbricids) due to human introductions. In some areas where it has been introduced, some people consider it to be a serious pest species since it is outcompeting native worms.
Through much of Europe, it is the largest naturally occurring species of earthworm, typically reaching 20 - 25 cm in length when extended (though in parts of southern Europe, the native species are much larger). In September 2012, a specimen was found in SW China measuring roughly 50 cm in length. It has an unusual habit of copulating on the surface at night, which makes it more visible than most other earthworms.