ABSTRACT
Soil is the upper most layer of earth crust, and it supports all terrestrial life. It is the interface between the lithosphere and the atmosphere, and strongly interacts with biosphere and the hydrosphere. It is a major component of all terrestrial ecosystems, and is the most basic of all natural resources. Most living things on earth are directly or indirectly derived from soil. However, soil resources of the world are finite, essentially nonrenewable, unequally distributed in different ecoregions, and fragile to drastic perturbations. Despite inherent resilience, soil is prone to degradation or decline in its quality due to misuse and mismanagement with agricultural uses, contamination with industrial uses, and pollution with disposal of urban wastes. Sustainable use of soil resources, therefore, requires a thorough understanding of properties and processes that govern soil quality to satisfactorily perform its functions of value to humans. It is the understanding of basic theory, leading to description of properties and processes and their spatial and temporal variations, and the knowledge of the impact of natural and anthropogenic perturbations that lead to identification and development of sustainable management systems. Soil science is, therefore, important to management of natural resources and human well-being.
