Soil Genesis and Development, Lesson 6 - Global Soil Resources and Distribution

This lesson discusses soil resources and functions at the global scale. Goals To introduce students to the basic functions of soil, and to evaluate regional differences in soil resources at the global scale. Objectives Identify and describe the roles of soil in the global ecosystem. Consider the impact of physical, chemical, and biological factors on soil functions. Identify cultural and environmental factors which affect the ability of soil to function. Evaluate the nature and extent of the global soil resource. [Figure 1. Though it is commonly taken for granted, soil is an indispensable component in the cycles of life on Earth. Image courtesy of Tim Kettler.] Consider a handful of soil (Figure 1). How does it appear to you, as dirt, minerals, or soil? At first glance it may appear very ordinary, something that you routinely take for granted. However, if we make a closer inspection, we find that soil is far from ordinary. It is the home of countless numbers of organisms, both easily visible and microscopic. The soil acts as the Earth’s recycler, filter, purifier, and storehouse. The soil ecosystem recycles dead organisms into the building blocks of new life, it transforms toxic substances into simple compounds, it renders pathogenic organisms harmless, and it purifies and stores water as it passes through. The soil is a dynamic living system which functions as the interface between land and sky, and the living and the dead. Soil is the repository of fertility and life on this planet. Even as the nature and properties of the soil vary greatly by location, its role in ecosystems and the ways in which it functions are basically constant from one place to another worldwide. This lesson will introduce you to the basic functions performed by all soils, consider environmental and cultural factors that enhance or degrade its ability to perform these functions, and address regional similarities and differences in soil type and quality on a global scale. Modules: Lesson home 6.1 - Introduction 6.2 - Functions of Soil 6.3 - Soil Quality 6.4 - Soil Orders 6.5 - Major Biomes 6.6 - Land Quality 6.7 - Land Stresses - Natural 6.8 - Human Populations 6.9 - Land Stresses - Anthropic 6.10 - Soil Moisture Regimes 6.11 - Soil Temperature Regimes 6.12 - References Glossar