Minerals, dead and living organisms (organic materials), air, and water make up soil. These four elements interact in amazing ways, making soil one of the most dynamic and vital natural resources on the planet. People use soil in a variety of ways. Soil science is concerned with soil as a natural resource on the earth's surface, including its creation, classification, and mapping, as well as the physical, chemical, biological, and fertility qualities of soils in general, as well as these features in connection to soil use and management. Paedology (the production, chemistry, morphology, and categorization of soil) and edaphology (the influence of soil on organisms, particularly plants), for example, are sometimes used interchangeably with soil science. Pedology (the production, chemistry, morphology, and categorization of soil) and edaphology (the interaction of soils with living organisms, particularly plants) are names that are sometimes used interchangeably with soil science. Soil scientists are concerned about how to conserve soil and arable land in a world where there is a growing population, a potential future water crisis, rising per capita food consumption, and land degradation.