Soils Online Study Guide

Current Issue 2003 Farmland Preservation

This page contains links that deal specifically with this year's Current Issue and wildlife habitat. Check the National Envirothon Page for more information on the Current Issue.

The 2003 Canon National Envirothon will be held in Maryland. The 2003 theme is based on Maryland's Agricultural Land Conservation and Farmland Preservation. The background for the theme is below.

Agricultural lands – cropland, pasture, and rangeland – form the economic, social, and cultural backbone of much of North America. Agriculture plays an important role economically, contributing hundreds of billions of dollars in gross domestic product annually. Millions of people are employed – directly and indirectly – in agricultural production. Farmland – including row crops, pasture, and range – covers hundreds of millions of acres.

Yet, productive arable agricultural lands – areas with fertile soils, adequate water, and a climate capable of producing food and fiber – are a finite resource.

For much of human history, soil erosion has posed a significant threat to agricultural lands and has had a significant impact on water quality. According to United States Department of Agriculture (USDA) 1997 Natural Resources Inventory, erosion carries away more than 2 billion tons of soil annually in the U.S. Considerable erosion also occurs on Canadian crop- and rangeland. In 1986, almost 15 percent of cultivated lands were affected by moderate and severe wind erosion. At a soil-loss rate of 10 tonnes per hectare, this means that at least 63 million tonnes of prairie topsoil were lost, according to Agriculture and Agri-Food Canada. During the past 20 years North America has experienced rapid commercial, economic, and residential growth, which continues today.

According to the USDA’s National Resources Inventory, an average of more than 1 million acres of agricultural land were developed in the U.S. each year between 1992 and 1997. As agricultural lands – including cropland, pasture, rangeland – are developed for other uses, we lose not only its food and fiber production and associated jobs, but also scenic viewscapes, wildlife habitat, wetlands, and open space.

According to Agriculture and Agri-Food Canada, between 1901 and 1996 Canada's cultivated land area expanded five-fold. In contrast, the supply of dependable agricultural land dropped by an estimated 16% over this period because of conversion to urban and other non-agricultural uses. In the 1980s, the area of land under cultivation in Canada surpassed the supply of dependable land. This situation indicates that agricultural production is becoming more reliant on marginal land, with possible effects on productivity, soil quality, wildlife habitat, and other environmental aspects.

Soil erosion and siltation has always been a part of a natural environmental process. The actions of man have accelerated this process through the use and misuse of land. During the 1930's, the culmination of several factors caused the development of a severe erosion problem in the United States. These factors including overworking of the soil, poor land use practices and an extended period of drought, were the cause of the "Dust Bowl", a term used to describe the huge storms that carried sediment from the Great Plains all the way to the east coast. One particular storm was so severe, dust was scattered on the decks of ships 200 miles out to sea and drove grit into the teeth of people in New York City! It also blotted out the sun in Washington, DC! During the 1930's over 100 million acres of farmland were destroyed.

Soil conservation efforts began in earnest in the United States in the 1930’s with the establishment of the Soil Conservation Service, now the Natural Resource Conservation Service (NRCS). In doing so, approved legislation lead to the formation of 3,000 soil and water conservation districts in the United States. Through years of dedication and commitment to farming, these local soil and water conservation districts have been key partners to the success of farmland conservation and preservation efforts. Several Canadian programs – the Canada National Soil Conservation Program and National Soil and Water Conservation Program (1997-1999) – have also dealt with soil erosion and conservation. Resource professionals from federal, state, provincial, and local agencies provide farmers the necessary assistance for the installation of best management practices to conserve and protect the farmland utilizing a land preservation program.

Federal, state, and provincial governments, and non-profit land trusts and land preservation organizations are working in various ways to facilitate the preservation of farmland. Farmland is continually being developed for other land uses that may destroy prime farmland, scenic viewscapes, or wildlife habitat.

We will provide opportunities for students to experience and gain knowledge about the management and stewardship of our natural resources through hands-on activities, authentic assessment, and personal contacts. The students will take home with them an understanding of how the quality of life is affected by the quality of our natural resources and will understand the need to conserve and preserve agricultural farmland.

Erosion Prediction

The Universal Soil Loss Equation, developed by Agricultural Research Service scientists, W. Wischmeier and D. Smith, is the most widely used model for erosion prediction. It is calculated using the formula below which takes into account rainfall, slope, slope length, soil erodibility, crop or land cover and conservation practice if any.

A = R x K x (LS) x C x P

where:

A = estimate average soil loss from sheet and rill erosion in tons per acre per year

R = rainfall and runoff erosivity index

K = soil-erodibility factor

L = length of slope factor

S = degree of slope factor

C = cropping-management factor

P = conservation practice factor

This model was put into its present developmental form during the 1950/60s by Mr. W.H. Wischmeier who held a joint appointment with USDA and the Department of Agricultural Engineering here at Purdue. The model is a phenomenological one (predicts the effect) and does not give a good idea of the actual mechanisms involved.

Evaluating the factors in USLE:

Taken from: Perdue University

R, the rainfall factor:

Most appropriately called the erosivity index; it is a statistic calculated from the annual summation of rainfall energy in every storm (correlates with raindrop size) times its maximum 30-minute intensity.

K, the soil erodibility factor:

This factor quantifies the cohesive character of a soil type and its resistance to dislodging and transport (particle size and density dependent) due to raindrop impact and overland flow shear forces.

LS, the topographic factor:

Steeper slopes produce higher overland flow velocities. Longer slopes accumulate runoff from larger areas and also result in higher flow velocities. Thus, both result in increased erosion potential.

C, the cropping-management factor:

This factor is represents the soil loss from land cropped under specified conditions to corresponding loss under tilled, continuous fallow conditions. For example, pasture, hayland and lawns have much less erosion than plowed corn and soybean fields.

P, the conservation practice factor:

Practices included in this term are contouring, strip cropping (alternate crops on a given slope established on the contour), and terracing.

There are other erosion prediction models including the Revised Universal Soil Loss Equation (RUSLE), the Wind Erosion Equation (WEQ) and others.

Highly Erodible Land

Highly erodible soil and potentially highly erodible soil are also listed in Section 11 of the Natural Resources Conservation Service (NRCS) Field Office Technical Guide. The criteria used to group highly erodible soils were formulated using the Universal Soil Loss Equation (USLE) and the wind erosion equation. Soil use, including tillage practices, is not a consideration. Areas defined as highly erodible can be held to an acceptable level of erosion by following approved practices in a conservation plan. Various conservation practices, such as residue management, reseeding to grasses, contour farming, and terraces, are used in conservation planning to reduce soil loss, maintain productivity, and improve water quality.

Prime Farmland

Prime Farmlands include all those soils in Land Capability Class I and selected soils from Land Capability Class II. Prime Farmland is land that has the best combination of physical and chemical characteristics for producing food, feed, forage, fiber and oilseed crops and is also available for these uses. It has the soil quality, growing season, and moisture supply needed to economically produce sustained high yields of crops when treated and managed according to acceptable farming methods, Prime Farmlands are not excessively erodible or saturated with water for a long period of time, and they either do not flood frequently or are protected from flooding.

Statewide Importance

Farmlands of statewide importance include those soils in land capability Class II and III that do not meet the criteria as Prime Farmland, These soils are nearly Prime Farmland and economically produce high yields of crops when treated and managed according to acceptable farming methods, Some may produce yields as high as Prime Farmland if conditions are favorable.

Locally Important

Farmland of local importance includes those soils that are not prime or statewide importance and are used for the production of high value food, fiber or horticultural crops.

Unique Farmland

Farmland of unique importance includes those soils that are not prime, statewide or local importance and are used for the production of specialty crops in a particular area. An example is special vegetable production in muck soils and cranberry production in acidic bog soils.

Hydrologic Group

1.  Definition - Hydrologic group is a group of soils having similar runoff potential under similar storm and cover conditions. Soil properties that influence runoff potential are those that influence the minimum rate of infiltration for a bare soil after prolonged wetting and when not frozen. These properties are depth to a seasonally high water table, intake rate and permeability after prolonged wetting, and depth to a very slowly permeable layer. The influence of ground cover is treated independently.

2.  Classes - The soils in the United States are placed into four groups, A, B, C, and D, and three dual classes, A/D, B/D, and C/D. In the definitions of the classes, infiltration rate is the rate at which water enters the soil at the surface and is controlled by the surface conditions. Transmission rate is the rate at which water moves in the soil and is controlled by soil properties. Definitions of the classes are as follows:

A Class. (Low runoff potential). The soils have a high infiltration rate even when thoroughly wetted. They chiefly consist of deep, well drained to excessively drained sands or gravels. They have a high rate of water transmission.

B Class. The soils have a moderate infiltration rate when thoroughly wetted. They chiefly are moderately deep to deep, moderately well drained to well drained soils that have moderately fine to moderately coarse textures. They have a moderate rate of water transmission.

C Class. The soils have a slow infiltration rate when thoroughly wetted. They chiefly have a layer that impedes downward movement of water or have moderately fine to fine texture. They have a slow rate of water transmission.

D Class. (High runoff potential). The soils have a very slow infiltration rate when thoroughly wetted. They chiefly consist of clay soils that have a high swelling potential, soils that have a permanent high water table, soils that have a claypan or clay layer at or near the surface, and shallow soils over nearly impervious material. They have a very slow rate of water transmission.

Online list of hydrologic soil groups for all soil series in the United States.

Taken from: U.S. Department of Agriculture, Natural Resources Conservation Service, 2002. National Soil Survey Handbook, title 430-VI.

2004 Current Issue - Natural Resource Management in the Urban Environment

This page contains links that deal specifically with this year's Current Issue and soils. Check the National Envirothon Current Issue Page for more information on this year's theme.

Learning Objectives:

• Soils/Land Use - Soil conditions greatly influence the growth and vigor of vegetation, the stability of structures, the drainage of storm water, and water quality in urban areas.
• Understand the common problems found in urban soils and suggest techniques to prevent or correct them.
• Discuss the soil characteristics necessary for vegetation growth and examine specific soil conditions found in urban areas.
• Explain how soil properties in urban areas affect the stability of structures and water quality.

Urban Soils

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Soil Erosion on Construction Sites (1.4 mb) 

Functions of Urban Soils

Urban soils are unique because they:

• are exposed to more intense land use versus forest or even agricultural soils
• must be able to withstand high volumes of pedestrian and vehicular traffic
• must support densely populated areas of buildings and roads
• must provide an adequate growth medium for trees and lawns

In some cases, a single urban soil may have to perform some or all of the above tasks simultaneously and usually within a very confined area. Compare this situation with a soil in a rural setting that may only have to support a road, or provide habitat for trees or row crops.

Impacts on Urban soils

• Because of their intense land use, urban soils are subjected to the following impacts:
• erosion and sedimentation
• compaction
• contamination
• disturbance

Although these impacts can also be found in non-urban setting, the intensity and a real extent of these impacts may be much greater in an urban area than they would be in a non-urban area.

Erosion and sedimentation on construction sites occurs when steps are not taken to protect the soil once it is exposed to the surface. Much of the natural soil can be carried off site by runoff if steps are not taken to prevent erosion.

Compaction occurs when the soil is traveled on by pedestrian and/or vehicular traffic during a time when the soil is moist or wet. Once compacted, the soil loses all its structure, which in turn affects the amount of water that can infiltrate into the soil. If the surface water cannot move into the soil, it will then travel across the ground surface as runoff, potentially carrying sediment with it.

 Soils can become contaminated either from a single catastrophic event, such as a fuel spill from a container leak, or could occur over time, such as when pollutants in the air from a factory fall to the ground.

Although tilling a farm field is considered disturbance, the disturbance related to urban soils usually occurs on a much larger scale. The types of soil disturbances that can occur in urban areas include mixing of soil horizons, adding or removing of topsoil, cutting/filling or grading of areas to level the ground surface, and filling areas of wet or undesirable soils.

The first line of defense against these impacts is to avoid their occurrence. Since this may not be possible, steps must be taken to correct these problems.

Further erosion on a site can be minimized by covering exposed soil with mulch. Sedimentation can be lessened by placing hay bales or silt fence at the base of actively eroding areas to capture any transported soil material. See “NRCS Soil Quality Urban Technical Note 1”.

Alleviating compaction problems in soils basically involves procedures that mechanically loosen the soil to reestablish soil structure, or at least increase infiltration into the soil. See “NRCS Soil Quality Urban Technical Note 2”.

Removal of contaminants, especially heavy metals, involves the use of chemical treatments, or in some cases utilizes plants that are able to uptake and remove contaminants from the soil. See “NRCS Soil Quality Urban Technical Note 3”.

Urban Soils and Soil Survey

Urban Soil/Parent Material relationships

Urban soils are different from other kinds of soil in that their parent material, the material from which the soil formed, is predominately disturbed material. In some cases, the parent material is natural soil material that has been disturbed in a manner such as described above (cutting/filling, adding/removing soil material); however, there are areas where the disturbed parent material is not soil material at all, but may be material transported from a source area. Examples of foreign fill material include:

• Dredge material
• Garbage
• Coal ash
• Fly ash
• Construction debris

Urban Soil Series

With regard to soil surveys, it was traditional for urban land to be considered a “miscellaneous area”, and was not represented in a soil survey as a soil series. However, in the past few years, some NRCS soil scientists have chosen to begin trying to identify soils formed in different kinds of fill material. The term “anthrotransported” has been coined to identify these types of material. Here is a small list of soil series, with reference to their parent materials, that have recently been proposed for use in soil surveys:

Bigapple - formed in anthrotransported soil material from dredging activities of nearby shorelines, waterways, bays or rivers.

Centralpark - formed in transported soil material. The transported soil material is relatively clean of refuse, with less than 10 percent pieces of plastic, glass, bricks, concrete, and metal.

Greatkills Series - formed in a mixture of household garbage and transported soil material.

Riker Series – formed in a mixture of coal slag, unburned coal fragments, and large pieces of coal used as railroad ballast.

Links:

1. NRCS Soil Quality Urban Technical Notes Series:

http://soils.usda.gov/sqi/soil_quality/land_management/urban.html

• Note 1: Erosion and Sedimentation on Construction Sites
• Note 2: Urban Soil Compaction
• Note 3: Heavy Metal Soil Contamination

2. Urban Soils - USDA Forest Service Southern Region Urban Forestry South website (link from National Envirothon webpage)

• USDA Forest Service, Urban Forestry South, Wildlife in Urban Areas

More Study Materials from the National Envirothon Website

Soil/Land Use- conditions greatly influence the growth and vigor of vegetation, the stability of structures, the drainage of storm water, and water quality in urban areas.

1. Understand the common problems found in urban soils and suggest techniques to prevent or correct them.

Urban Soils

2. Discuss the soil characteristics necessary for vegetation growth and examine specific soil conditions found in urban areas.

Chapter 7: Site Assessment and Soil Improvement

3. Explain how soil properties in urban areas affect the stability of structures and water quality.

Natural Resource Conservation Service - Urban Soil Issues

Natural Resources Conservation Service - Soil Facts

2007 Current Issue - "Alternative/Renewable Energy"

Note to Contestants and Advisors: answers for questions for the 2007 NJ Envirothon Soils Exam will be taken directly from this supplemental information. Website links and publications listed in this information are for reference purposes only, but may be used to further one’s knowledge on each topic discussed.

Learning Objectives

Identify and understand issues of traditional and innovative energy sources related to:

1. agricultural and forested lands
2. soil erosion control

Issues of traditional and innovative energy sources related to Agricultural Lands

Agricultural lands would most likely be used for crop production to produce source plant material for the production of biomass fuels. Examples of such crops may include:

• corn and other starch-rich crops grown for the purpose of making ethanol
• soybeans and other oil-rich crops grown for the purpose of making renewable diesel fuel, or “biodiesel”.

For more information on these topics, refer to the following websites: http://www1.eere.energy.gov/biomass/ethanol.html and http://www1.eere.energy.gov/biomass/renewable_diesel.html

Therefore, the potential impacts on these lands would be consistent with those of any agricultural lands in crop production. These impacts arise due to the fact that the soil will undergo some form of tillage and the crop will be removed, leaving little crop residue behind. The potential impacts include:

• soil erosion due to tillage operations and removal of crop residue that exposes bare soil
• loss of organic matter and nutrients due to soil erosion and removal of crop residue
• loss of soil organisms, such as microbes, fungi, and earthworms, due to crop residue removal
• loss of available soil water due to evaporation of soil water from bare soil surfaces, which may also affect the drought resistance of the crops
• poor germination of crops due to lower soil temperatures in colder climates.

To counteract these potential impacts, the following recommendations may limit the abovementioned detrimental effects to the soil. These recommendations include:

• tailoring crop residue removal rates to particular crops and soil types, as different crops produce different levels of residue, and different soil types can tolerate higher residue removal rates. Enough residue should be left behind to provide a certain level of soil surface protection
• applying additional conservation practices, such as contour cropping or conservation tillage, to help compensate for the potential loss of erosion protection due to the removal of crop residue
• growing crops that are specifically tailored for biofuel production, such as switchgrass or hybrid poplar
• periodic monitoring and assessment of crop fields to ensure that none of the detrimental effects of crop production, such as erosion or nutrient loss, are occurring. Fertility tests should be conducted periodically to ensure that organic matter and nutrient levels are optimal for crop production.

For more information on this topic, refer to the following website: http://soils.usda.gov/sqi/management/files/AgForum_Residue_White_Paper.pdf

Issues of traditional and innovative energy sources related to Forested Lands

Forested lands would most likely be used directly for production of wood as source plant material, or indirectly as a source of wood waste generated from the production of wood products such as lumber and paper pulp. Examples of such materials may include:

• pulp and paper industry byproducts such as hogged (chipped) wood, bark, and spent “black liquor” (the pulping-process residue remaining after removal of the cellulose for papermaking). These materials can be used to generate electricity, heat, and steam in either biomass fueled electrical power plants or in combined heat and power (CHP) facilities.

For more information on this topic, refer to the following website: http://www1.eere.energy.gov/biomass/industrial_process.html

Therefore, the potential impacts on these lands would be consistent with those of any forested lands in wood production. These impacts arise due to the fact that the soil may be affected by some operation related to the harvesting of wood products. The potential impacts include:

• erosion during road construction
• erosion during logging operations

For more information on this topic, refer to the following publication: Soil Survey of Ocean County, New Jersey, USDA-SCS, 1980

To counteract these potential impacts, the following recommendations may limit the abovementioned detrimental effects to the soil. These recommendations include:

• using logging equipment only when site and soil conditions are favorable for maintaining site productivity and minimizing soil erosion
• installing drainage control measures, such as roadside ditches and surface crowning of access roads and trails, to minimize water flows across bare soil areas
• installing erosion control measures, such as vegetative or non-vegetative cover (gravel), on trails and log landings to minimize erosion rates. This can be done during logging operations as needed and after logging operations have ceased.

For more information on these topics, refer to the following websites: ftp://ftp-fc.sc.egov.usda.gov/NHQ/practice-standards/standards/560.pdf and ftp://ftp-fc.sc.egov.usda.gov/NHQ/practice-standards/standards/655.pdf

Check the 2007 National Canon Envirothon webage for links and more information.

For more information contact your local Soil Conservation District Office or Richard Belcher, NJ Envirothon Coordinator Phone: (609) - 292-5540,  Fax: (609) - 633-7229.

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This Page Last Updated February 07, 2008