Soil and Land Use Study Guide
Created by the Erie County NY Envirothon
There can be many uses of the word “soil”, depending upon the context. For example, soil can be thought of as an engineering material for road construction, as dirt on clothing, as a mixture of ingredients for growing potted plants, or what the farmers plow every spring.
For the purposes of the regional Envirothon, “Soil is the collection of natural bodies on the earth’s surface, in places modified or even made by man of earthy materials, containing l living matter and supporting or capable of supporting plants out-of-doors.” Soil is thus considered both a product of nature and a critical part of natural systems. This definition also allows soils to be collectively grouped into a classification system, as used in making soil surveys.
Soils “begin” as parent material, and then the process of weathering occurs. Weathering eventually causes a differentiation into distinct horizons. A soil and its profile show the effects of five soil forming factors: Climate, Living Organisms, and Topographic Relief, Parent material and Time (it may help to remember the word “CLORPT”). Soils can be considered as “young”, “mature” or “old”, depending upon their extent of weathering and horizon development. Soils in NY State are relatively young or mature, but not old – their parent material was exposed or deposited during the relatively recent retreat of glaciers, some 10 to 15 thousand years ago.
There are a number of soil properties and limitations including: composition, texture, structure, slope, color, chemistry, profile, permeability and drainage. In addition to defining and applying these soil properties for background, a practical knowledge of the soils can be attained by using the Soil Survey, which classifies soils into series for identification, provides reference maps and interpretative tables.
Most of the soils in the U.S. are aerobic. But soils can often become saturated with water due to rainfall and flooding. When this anaerobic (no oxygen) environment continues for long periods during the growing season, different biological and chemical reactions begin to dominate. In soils where saturation with water is prolonged and is repeated for many years, unique soil properties usually develop. Soils with these unique properties are called hydric soils. These soils are important favor the formation of many types of wetlands. In fact, hydric soils were defined so that they help identify wetlands.
Soil erosion and sedimentation are separate processes, but think of them as occurring together, since once soil is eroded, it will eventually become sediment impacting water quality somewhere else. Normally it takes an average of 500 years for nature to build up 1 inch of topsoil. To grow good crops agriculturally, 6 inches of topsoil are required. Since only 1/500th of an inch of topsoil is being built up naturally on the average annually in the U.S., soil is being depleted on the average each year approximately 18 times faster than it is being built up in nature.
___________________________________________________________________________________________
Soil and Land Use Learning Objectives
For successful completion of the soils/ land use section, students should be able to:
- Know the five soil forming factors, and understand how they influence soil properties.
- Understand the origin and types of soil parent materials and land forms.
- Understand basic soil forming processes: additions, losses, translocations, and transformations.
- Recognize and understand features of Soil Profiles, and be able to use this information to determine basic soil properties and limitations.
- Identify and describe soil characteristics (texture, structure, and color- using Munsell color charts).
- Understand soil biological diversity and how it relates to soil health and hence plant, human and environmental health. Recognize that understanding soil ecosystems is important to soil management.
- Understand how the hydrologic, carbon and nutrient cycles relate to soil management.
- Understand that soil fertility relates to the physical and chemical properties of the soil in addition to the quantity of nutrients.
- Understand why soil fertility reflects the physical, chemical and biological state of the soil.
- Compare different land uses and conservation practices and their impact on soils and erosion.
- Understand how soil is impacted by point & non-point source pollution and practices used to address, reduce or eliminate the impact.
- Access and use published and on-line soil data and other resources to learn how land use affects soil, and the limitations of local soils.
- Understand Land Capability Classes and how they are important in determining appropriate land use.
- Understand soil drainage classes and be able to recognize the characteristics of hydric soils and know how soils fit into the definition of wetlands.
We have attempted to find the most recent information from creditable, university or governmental based institutions related to the listed learning objective but please note that the following resources are not all inclusive or exclusive and there are many other sources of information that you may wish to consult in your study of Soils and Land Use.
_________________________________________________________________________________
Soil and Land Use References