Soil is our life support system: it filters our water, provides essential nutrients to our forests and crops, and helps regulate the Earth's temperature as well as many of the important greenhouse gases; Soil provides habitat for billions of organisms, contributing to biodiversity; and supplies most of the antibiotics used to fight diseases. Soil is the basis of our nation's agroecosystems which provide us with feed, fiber, food and fuel. Humans use soil as a holding facility for solid waste and foundation for our cities and towns.

Water is an essential component of this system. Globally two-thirds of all fresh water is held in soils as soil moisture, soil 'reservoir ', or green water, accessible to plant, only one tenth of fresh water is blue water - stream flow and groundwater that can be abstracted for general use. Functionality and evolution of soil 'reservoir' is a crucial and driving force for the terrestrial ecosystems development - so long as the 'soil reservoir' function is properly maintained, the whole eco-system can be better protected.