Soil Conservation

Soil Conservation

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The United States was blessed with abundant fertile soil when the colonists first arrived, and the need to maintain that fertility did not immediately arise. Soon after the introduction of intensive tobacco farming, however, it became clear that this crop had a devastating on the quality of the soil if planted year after year without interruption.However, as long as the frontier presented fresh fertile land, the problem of soil degradation was never a crisis. The situation was exacerbated by the high prices paid by Europeans for food during World War I, which led to an expansion of land under cultivation beyond what could be sustained in peacetime.The onset of The Great Depression coincided with a combination of bad weather and the culmination of bad Farming practices that produced the Dust Bowl conditions of 1931 and 1933. Renamed the Soil Conservation Service within the Department of Agriculture, the agency developed demonstration projects across the country in selected watersheds.In 1938, the National Emergency Council sent a report to Roosevelt on economic conditions in the South. Its comments on the situation with regard to soil were particularly devastating:

Nature gave the South good soil. With less than a thirdof the Nation`s area, the South contains more than a thirdof the Nation`s good farming acreage. It has two-thirdsof all the land in America receiving a 40-ineh annual rain-fall or better. It has nearly half of the land on which cropscan grow for 6 months without danger of frost.This heritage has been sadly exploited. Sixty-one per-cent of all the Nation`s land badly damaged by erosion isin the Southern States. An expanse of southern farm landas large as South Carolina has been gullied and washedaway ; at least 22 million acres of once fertile soil has beenruined beyond repair. Another area the size of Oklahomaand Alabama combined has been seriously damaged by ero-sion. In addition, the sterile sand and gravel washed offthis land has covered over a fertile valley acreage equal insize to Maryland.

A Brief History of Farm Conservation Policy

Across the divide from the challenging realities of regulating nonpoint source pollution and agriculture reside the natural resource conservation policies for farmers contained in the omnibus legislation commonly known as the farm bill. The suite of conservation programs tend to avoid the sharp-edged debate surrounding environmental regulation, as well as the harsh criticism aimed at their sibling policies for commodity supports in Title I of the farm bill. They are, however, related to the issue of environmental regulation of farming and part of the universe of policies that impact farming on the ground.

Historical Discussion

Farm conservation policy was born of the dramatic Dust Bowl disaster of the 1930’s, when the soils of the Great Plains darkened the skies over the U.S. Capitol during Hugh Hammond Bennett’s testimony before the Senate Agriculture Committee about the need for legislation to conserve topsoil. Spurred to action by this unfolding disaster in the plains descending on the East Coast, Congress passed the Soil Conservation Act of 1935. This legislation established a national policy for the conservation of soil with the newly-named Soil Conservation Service at the helm. The law also eventually led to the creation of soil conservation districts in the states to help with land use planning.

A year later, the Supreme Court threw out a law providing commodity price support programs designed to help farmers survive the devastating Depression. The cornerstone of this law was a policy to manage commodity supplies by paying farmers to reduce planting and production the Supreme Court found regulation of agricultural production to be outside the bounds of Congress’ authority as provided in the Constitution and declared the law unconstitutional. Still mired in the Great Depression, farm leaders searched for a solution. They settled on combining the production management concepts with soil conservation, passing the Soil Conservation and Domestic Allotment Act of 1936 a month after the Supreme Court decision. Soil conservation was considered well within Congressional authority to provide for the general welfare of the nation – likely an easier argument in light of the Dust Bowl. The new act provided payments to farmers who reduced their plantings of “soil-depleting” crops (which were also the same crops Congress had been attempting to support) and switched some acreage to crops such as grasses and legumes considered to conserve soils. Thus began in earnest the national effort to improve on-farm conservation, albeit significantly tied to the policies for increasing farm prices and income. The 1936 Act also provided assistance payments for implementing practices such as terraces and even planting cover crops.

World War II’s demands for increased production are seen as having resulted in a de-emphasis of conservation policies as the war needs shifted the national and farm policy focus. The post-war commodities markets brought significant farm surpluses and low prices problems that kept much of the policy focus on supporting prices and farm incomes. In 1956, Congress returned to conservation policy as method for helping remove acreage from production, creating the Soil Bank as part of the Agricultural Act of 1956. The Soil Bank involved both an acreage reserve program that provided rental payments for reduced plantings of certain crops and a conservation reserve program that provided for a long-term land-retirement program, removing 29 million acres from production.

The Soil Bank programs continued through the surplus years of the late-1950’s and the 1960’s until strong international demand in the 1970’s pushed farm policy in a different direction, with USDA calling on farmers to plant “fencerow to fencerow” to meet demand. While some conservation policies continued, they appear to have been minimalized and lacked clear focus even as a rising environmental movement succeeded in passing the Clean Water Act and the Clean Air Act. In 1977, Congress passed the Soil and Water Resource Conservation Act requiring a comprehensive review of conservation programs to be used in the design of improved, new programs.

Expanded production in the 1970’s was followed by a collapse of prices and incomes in the 1980’s bringing about a second farm crisis as well as ushering in a renewed focus on conservation policies, particularly by an empowered environmental community. The Food Security Act of 1985 was the first farm bill with a specific title devoted to conservation programs and policies it marks the clearest turning point in conservation policy and its relation to farm policy. The 1985 Farm Bill included the Conservation Reserve Program (CRP) in its current form and operation, but most notably it included conservation compliance requirements: to be eligible for commodity subsidies farmers had to comply with provisions known as swampbuster (addressing the draining of wetlands), sodbuster (addressing the plowing of native sod) and requirements conservation planning for any farming on Highly Erodible Land. All farm bills since 1985 have contained conservation titles and each has been written as amendments to that bill conservation compliance has also remained a significant part of farm bill debates as evidenced by the Agricultural Act of 2014’s linking compliance to eligibility for crop insurance premium assistance.

In the wake of the direction established by the 1985 bill, legislation in the 1990’s expanded conservation programs. The 1990 Farm Bill (the Food, Agriculture, Conservation, and Trade Act of 1990) added the Wetlands Reserve Program (WRP, providing easements to restore and maintain wetlands) and the Ag Water Quality Protection Program. The 1996 Farm Bill (the Federal Agricultural Improvement and Reform Act of 1996) extended CRP and created a new program, the Environmental Quality Incentives Program (EQIP) which replaced the existing Agricultural Conservation program and consolidated other programs in an attempt to improve conservation outcomes, efficiency and effectiveness. The 1996 bill also created the Wildlife Habitat Incentives Program (WHIP).

Expansion of conservation policies continued in the 2000’s. The 2002 Farm Bill (the Farm Security and Rural Investment Act) reauthorized the existing suite of conservation programs, including EQIP with some revisions and a significant increase in funding to $1.3 billion per year. WRP, the Grasslands Reserve Program, a program to protect farmland from development and more were continued. The 2002 Farm Bill also added the Conservation Security Program (CSP) a new program with a different focus, seeking to achieve natural resource conservation within farm production, known as “working lands” conservation. CSP was modeled after green payment program proposals in that it provided farmers payments on a dollars-per-acre basis over a 5-year contract to adopt, maintain and improve conservation across their entire farm, as opposed to cost-share assistance on specific conservation practices. Finally, the 2002 Farm Bill capped the amount of acres that could be enrolled in CRP at 39.2 million acres.

Following in its footsteps, the 2008 Farm Bill (the Food, Conservation, and Energy Act of 2008) maintained a significant focus on conservation policy by continuing the general suite of conservation programs. The Conservation Security Program was revised in the wake of significant problems in its implementation by USDA and renamed the Conservation Stewardship Program (CSP). It maintains the working lands, operation-wide focus on conservation but is given operational adjustments to improve its effectiveness, as well as substantial, long-term funding and a charge to add over 12 million acres to the program each fiscal year. By comparison, the CRP acreage cap was lowered to 32 million acres and changes were made to the program to permit enrollment of farmable wetlands, buffers and other similar practices that depart from the traditional reserve concept, moving in the direction of working lands conservation.

The Agricultural Act of 2014 continued the above-discussed trend even in the face of demands for reducing spending across farm bill programs. In general, conservation title spending was reduced by an estimated $4 billion over the 10-year budget window — a reduction that was substantially less than the reduction to Title I subsidy programs and even less than for the Supplemental Nutrition Assistance Program. Moreover, spending on conservation is now estimated to surpass spending on Title I subsidies an historic shift in policy priorities. Much of the savings in the 2014 Farm Bill comes from a reduction in the acreage cap for CRP, moving the cap down from 32 million acres to 27.5 million, 26 million, 25 million and finally to 24 million acres over the five fiscal years of the bill. Other major changes involved consolidating the easement programs (Wetland Reserve, Grasslands Reserve and Farmland Protection) into a single Agricultural Conservation Easement Program. CSP is further revised to improve on-the-ground operation and spending for it is reduced. Finally, a host of programs and authorities were consolidated into a single program — the Regional Conservation Partnership Program (RCPP). RCPP is notable in that it takes further the concept of working lands, bringing in private partners and private resources to achieve conservation on a large-scale, regional basis across multiple programs and coordinated among numerous producers. The program also seeks comprehensive assessment of the impacts of conservation practices on the natural resources it seeks to conserve.

Farm-based, natural resource conservation policy effectively began as a product of the twin disasters of the 1930’s: the Dust Bowl and the Great Depression. For much of its history its existence was closely linked to, if not dependent upon, commodity support policies, often as a tool to help manage or control production and supplies. The 1985 Farm Bill sent conservation policy off on a different trajectory. Over the last 20 years the policy focus has rapidly shifted away from land retirement towards conservation as a part of production — working lands conservation to address resource concerns by building on stewardship principles at the heart of responsible farming.

The history of soil conservation: This is not a new problem!

Soil erosion is one of the biggest land degradation issues plaguing the current world. I’ve touched on this topic in the land degradation series. However, a recap is warranted:

  • Today, we are losing 30-40% of the world’s arable soil due to erosion every year, according to FOA.
  • That is equivalent to 3 football (soccer) fields worth of topsoil every minute.
  • At this rate, we will be able to practice agriculture only for 60 more years, according to a Scientific American article.

You would think that this has been a problem only since we have started changing age-old agricultural practices by using chemicals and mass producing grains to feed the growing population. However, that is not true…

Civilizations of the past have all faced the problems of soil erosion and have actually fallen because of this. That’s right: civilizations have fallen because of soil erosion.

The old days

The middle eastern civilizations of the past have been prolific in their advancements in war, law and order and science. However, they have fallen prey to the problems of deforestation, soil erosion and salt buildup. Simeria, in 2700 BC., was a successful and prosperous community. But, by 2100 BC., the civilization had fallen prey to poor land management. As these civilization continued to move north towards Assyria and Babylonia, they didn’t seem to learn and continued to make the same mistakes.

In the year 1200 BC., Troy (popularly known for the Trojan Horse) faced a similar problem. Deforestation and erosion resulted in the shifting of the coastline continuously, throughout the Trojan regime. Only when this buildup was accounted for, the city was rediscovered in 1870.

Simultaneously, the Greek coastal cities just east of Troy were becoming land locked due to increasing soil erosion and sedimentation.

Across the world, Central American city states continued the wonderful tradition of degrading soils. Civilizations rose and fell constantly from 1700-1500 BC.

In fact, the problems of soil erosion seems to have affected those civilizations that had developed advanced methods of agriculture coupled with rampant deforestation. Both have been a direct consequence of growing population, and has resulted in the eventual fall of that civilization.

Did someone see the dangers of soil erosion?

Soil erosion was first recognized in the modern world by Jared Elliot in 1685. He recorded his observations in a series of essays, and was deeply concerned about water running down bare hillslopes. He was one of the earliest in his time to conduct experiments on conserving soil. He planted green crops to make the soil firm and enriched, and planted grasses and legumes for livestock management.

In fact, he wasn’t the only one. While the West continued poor soil practices, human settlements in the East, most notable China and India, understood the importance of soil preservation and practiced a lot of the current conservation techniques like terracing, crop rotation and the use of natural fertilizers. Early British settlers have recorded their first impressions of hill slopes lined in the form of terraces for agriculture in these regions.

However, western influences coupled with the need to feed the increasing number of mouths has forced these countries to forget their historic practices and resort to the short-term gains of the modern practices today.

What about today?

The biggest reason why history will continue to be relevant as long as humans live is to prevent the same mistakes being made over and over and over again. For some reason, however, humans tend to make them in new and more profound ways!

Soil erosion and deforestation has claimed countless civilizations, some well-known ones as well. It’s latest victim, however, looks like it will be it’s biggest victim of all. If the agricultural system of the current world fails, it is not one or two isolated civilizations that will fall. It is the entire world. Our interconnectedness, in this case, will be a bane.

SWCS Headquarters

The SWCS international headquarters building is located in the heart of the Corn Belt, between Des Moines and Ankeny, Iowa. This historical building was constructed in 1962 on land leased from Iowa State University at $1.00 per year through a 99-year lease. This generous arrangement was made possible because the land was an unused corner of an Iowa State experimental farm with little value for production. Built in a then-modern design, the building was intended to serve as &ldquosymbol of men and women dedicated to conservation for the welfare of people throughout the world."

Over the years, the building, which is dedicated to Hugh Hammond Bennett, has served as home to his library of conservation resources and archived documents, housed a full printing press and production staff for the Journal of Soil and Water Conservation, and provided a central location for conservation work from around the United States and world.

As Iowa State sold the experimental farm and the surrounding land became urbanized, the SWCS headquarters has remained intact. The six acres on which the building is situated are prairie soils&mdashNicollet loam and Webster silty clay loam. A small pond and wooded area add habitat to the east side of the property. Wildlife include deer, foxes, turtles, hawks, and an owl.

Visitors often comment on the unusual and striking building among newly developed, suburban surroundings. Please feel free to stop by to see us if you&rsquore in the area!


The soil survey program in the United States began in the late 1890's. The first soil survey in Iowa was of the Dubuque County area. Field work was completed in 1902 and the report was published in 1903. The &ldquolife&rdquo of a soil survey is estimated to be about 30 years so all 99 Iowa counties have had multiple surveys.

Beginning in the mid 1960's Iowa began an accelerated effort to map all counties in a short time. The agencies involved were the USDA Soil Conservation Service (now USDA Natural Resources Conservation Service), Iowa Department of Soil Conservation (now Division of Soil Conservation, Iowa Department of Agriculture and Land Stewardship) Iowa State University through the Experiment Station and Cooperative Extension Service and the counties. Costs were shared equally among federal, state, and county.

Most counties were mapped at a scale of 1:15840 (4 inches = 1 mile) on an aerial photo base. Approximately 12 person-years were required to map a 16 township county.

Soil surveys have gone through many phases over time. Since the initial surveys our knowledge of soils has increased, methods of collecting and presenting data have improved, and the present surveys are more detailed and accurate. However, soil surveys have always followed the same procedures of mapping, classification, correlation, interpretation, and publication.

Mapping is the delineation of soil boundaries on a base map which at the present time is an orthophotograph. A soil map of a tract of land is shown in Figure 1. Each polygon on the map is called a delineation and contains a number to identify the soil, a letter to define the slope group, and if needed, a number that identifies the erosion phase. The number 2 is used for moderately eroded which is interpreted as 3 to 7 inches of topsoil present. The number is 3 for severely eroded indicating that there is less than 3 inches of topsoil present and mixing of subsoil material has occurred because of tillage. If no number is present, the soil erosion phase is none or slight indicating that more than 7 inches of topsoil is present. All delineations containing the same set of symbols is called a map unit, for example 138C2. The number 138 identifies the Clarion soil series. In Iowa, a statewide legend is used to identify soil series and each series has a unique number. The letter C identifies the slope group as 5 to 9 percent, and the number 2 identifies the area as moderately eroded. Other symbols on the map show drainageways and contrasting soil areas that affect soil use but are too small (generally less than 2 acres) to show as a separate delineation. For example, the small circle with a plus sign indicates a wet depression with restricted permeability is present in a 107 (Webster) delineation in the upper middle of Figure 1.

Classification is the systematic arrangement of soils into groups or categories. The present system of soil classification used throughout the United States and many other countries is Soil Taxonomy. The lowest category in the system is soil series which in the above example is Clarion. The highest category is order. Soil Taxonomy includes 12 soil orders. Six of the 12 orders are mapped in Iowa. These are: Alfisols, Entisols, Histosols, Inceptisols, Mollisols, and Vertisols. Mollisols and Alfisols are the dominant orders occurring in Iowa.

Correlation is a nation-wide process to ensure that soil series names are defined and used consistently. For example, a soil named Clarion has the same set of soil properties as a result of the impact of a particular set of soil-forming factors wherever the Clarion name is used.

Interpretation describes the prediction of soil behavior for specific uses or management based on inferences from soil properties. They may be either qualitative or quantitative estimates of soil behavior.

Publication consists of compilation of soil information of a survey area to include descriptions, properties, classification, interpretations, and maps. Publications are available in hard copy and digital format. Starting in 2007 newly published county soil surveys are available only in digital format at:

In addition county soil survey reports are available on DVDs or CDs that can be obtained at soil and water conservation district offices or at the Iowa State University Extension and Outreach Online Store.

Additional soil and land use information plus a state-wide soil data base named the Iowa Soil Properties and Interpretations Database (ISPAID) are available.

A great advance in contributing to improvement of soil surveys was the use of aerial photographs. They came into common usage in the late 1930&rsquos. Their use greatly increased the precision with which soil boundaries could be delineated on maps. Another important variable is the scale at which the soil map is made. Early surveys were made at a scale of one inch per mile. Beginning in the late 1950&rsquos and continuing until 1990, the most common scale of mapping was 4 inches per mile. Since 1990, the scale used is 1:12,000 which is 5.28 inches per mile.

Understanding of soils, their development and properties is based on a knowledge of the five classic factors of soil formation: climate, organisms, topography, parent material, and time. Because of intensive use of the soil, human activity is considered by many to be a sixth soil forming factor. The need for updates of soil surveys will continue as our knowledge of the interactions of the above factors continues to increase with introduction of new technologies including improved remote sensing techniques, Light Detection And Ranging (LiDAR), smart phones, and many other innovations.

Figure 1. A soil map showing soil map symbols, drainage and spot symbols.

Prepared by Thomas E. Fenton and Gerald A. Miller, Emeritus Professors of Agronomy, Iowa State University. Article is modified version of original article published in Iowa Water Center 2011 report: Fenton, Thomas E. 2011. The Soil Survey in Iowa. Pp. 24-25 in Getting Into Soil and Water. Iowa Water Center, Iowa State University, Ames. 40 pages.

Soil Conservation

by Douglas Helms, 2006
Additional research provided by Joan E. Freeman.

Climate and landscape make much of North Carolina susceptible to soil erosion. Intensity and duration of rainfall, the measures of the rain's erosive power, are greater in the Southeast than elsewhere in the continental United States. During the nineteenth century, inefficient farming practices contributed significantly to the erosion of North Carolina's complex and varied soils when North Carolina cotton, tobacco, and corn farmers hitched animal power to plows and cultivators to clean-till widely spaced rows, gullies opened on the landscape and the rivers ran red with clay sediments.

Southerners struggled to invent indigenous methods of soil conservation. Nicholas T. Sorsby, a North Carolina native, developed a system of farming around horizontal (contour) plowing and hillside ditching. Written first for the North Carolina Agricultural Society, his Horizontal Plowing and Hillside Ditching (1860) was the only book available on these conservation methods prior to the Civil War. Priestly H. Mangum developed the Mangum terrace around 1885 on his farm near Wake Forest. The broad-based terrace became widely adopted in the South and was advocated by various state agricultural agencies. The North Carolina Agricultural Experiment Station in West Raleigh experimented with terracing and by 1896 advocated Mangum terraces to the state's farmers. By 1915 Cleveland County had terraces on 6,000 acres, earning the moniker, the "county of terraces." Terracing was hardly a panacea and in fact sometimes concentrated runoff, causing gullies. Crop rotations of grasses, hay, legumes, or close-growing small grain crops protected the soil from raindrop impact through part of the year and added organic matter to the topsoil, thus increasing the rate of rainfall infiltration. However, the system of agriculture based on clean cultivated row crops made soil conservation a difficult proposition.

Hugh Hammond Bennett, a native of Anson County, earned the title "father of soil conservation" through his efforts to awaken the country to the impact of soil erosion on food production and the economic health of rural communities. Bennett graduated from the University of North Carolina in 1903 and joined the Bureau of Soils in the U.S. Department of Agriculture (USDA). His concern over soil was born of tramping southern fields while making soil surveys. In September 1933, after waging a campaign to start some watershed-based demonstrations of soil conservation with New Deal emergency employment funds, he became head of the Soil Erosion Service, later the Soil Conservation Service (SCS), an agency of the USDA whose main purpose was to help farmers use their land and water resources wisely, thus preventing or reducing loss of soil by flood or erosion. One of several demonstration projects in North Carolina included the Bennett home place in the Brown Creek watershed. When the Soil Conservation Service began extending help to landowners through locally organized and directed soil conservation districts, the Brown Creek Soil Conservation District became, on 4 Aug. 1937, the first recognized by the USDA. The SCS, today the Natural Resources Conservation Service, continues to work with districts, farmers, and local governments and groups throughout the state on soil conservation and other resource matters.

Beginning in the fall of 1934, the Soil Erosion Service and the National Resources Board undertook a national reconnaissance erosion survey all 100 North Carolina counties have at least one published soil survey for comparison and land management purposes, and certain soil types are named after North Carolina locations: Alamance, Ashe, Conetoe, Fuquay, Georgeville, Goldsboro, Hyde, Mayodan, Pungo, Secrest, Wadesboro, Wake, and White Store. In this survey, erosion was found not to be severe in the Coastal Plain due to the region's gentle slopes combined with sandy soils, which allow rapid infiltration of rainfall and produce some of the richest farmland.

The story in the Piedmont and Mountain regions was very different. The loamy soil of the Piedmont is mostly sandy, red clay, producing some of the best farmland in the state with the greatest variety of crops, including cotton, tobacco, timber, small grains, hay, and corn. In the Mountains, the soils are usually a grayish brown loam, stony, shallow, and on steep slopes, allowing extensive pastureland and some crops of corn, hay, cabbage, and burley tobacco on properly terraced land. However, a soil type designated as Cecil, which covered large areas of the Piedmont, originally had a surface layer of sandy loam 12 to 14 inches thick underlain by 2 to 6 feet of heavy clay. The surface layer had been removed on much of the area. Statewide, the survey teams calculated that 9 percent of the land exclusive of water and large cities had lost three-fourths of its topsoil, 30 percent of the land had lost one-fourth to three-fourths of its topsoil, and 13 percent of the area had been gullied to some extent.

Two trends in land use have reduced soil erosion from cropland in North Carolina. First, there was a decrease in statewide cropland from about 7.7 million acres in 1949 to less than 5 million acres by the late 1990s. Second, land used for crops has been shifting from the Mountains and the Piedmont to the gentler slopes of the Coastal Plain. Comparing 1949 with 2004, Piedmont cropland shrank from 3.4 million acres to 929,000 acres, and Mountain cropland acreage decreased from 819,222 acres to 308,000 acres. Cropland in the Sandhills dropped from 128,648 acres to 61,469 by the early 1990s, and in the same period Coastal Plain cropland declined less severely from about 2.1 to 1.8 million acres. The flatwoods of the Coastal Plain remained fairly constant, with 932,254 acres in 1949 and 897,634 acres by 1992. The Tidewater section actually increased in total acreage, from 334,063 acres in 1949 to 565,448 acres in 1992.

Arthur R. Hall, "Soil Erosion and Agriculture in the Southern Piedmont: A History" (Ph.D. diss., Duke University, 1948).

William D. Lee, The Early History of Soil Survey in North Carolina (1984).

Angus McDonald, Early American Soil Conservationists (1941).

Roy W. Simonson, Historical Aspects of Soil Survey and Soil Classification (1987).


During the Dust Bowl era soil erosion caused severe dust storms in many parts of the United States. A 1934, an Idaho soil erosion survey revealed that more than 27 million acres of land (roughly half the state), had serious soil erosion problems. As a result, the U.S. Soil Conservation Service (later named the Natural Resources Conservation Service) was formed in the mid-1930s by Congress. The Idaho Soil Conservation Commission was established in March of 1939.

The Commission was originally to help form and coordinate soil conservation districts at the county level. As districts formed here, NRCS and the Conservation Commission began to promote new practices in production agriculture that protected the land. Farmers and ranchers were elected as District Supervisors, adding experienced local leadership to the federal/state partnership. This continues today. Over time, we moved beyond soil erosion to addressing water quality and quantity, plants, animals, and air issues too.

The Commission was part of the Idaho Department of Lands until 1997 when the Legislature moved the Commission’s enabling statute under the Idaho State Department of Agriculture (ISDA). In 2010 the Legislature renamed us the “Soil & Water Conservation Commission”, and granted the Commission autonomy (while leaving us under the statutory enabling statute of the Idaho State Department of Agriculture since the number of state departments is limited in the Constitution).

Read more about Idaho’s conservation history here: Serving People and the Land, Part I and Serving People and the Land, Part II, a History of Idaho’s Soil Conservation Movement.

A snapshot of soil conservation

As you can see, soil conservation has a long history in Australia. We have also published other historic films on our YouTube channel.

For other historical material, you can also check out:

  • the extensive set of publications and images on Trove
  • the Soil Conservation Service Journal from 1945-1982 and 1982-1988
  • the author and subject lists from the Soil Conservation Services Journal since 1945.


Contour ploughing orients furrows following the contour lines of the farmed area. Furrows move left and right to maintain a constant altitude, which reduces runoff. Contour ploughing was practiced by the ancient Phoenicians for slopes between two and ten percent. [4] Contour ploughing can increase crop yields from 10 to 50 percent, partially as a result of greater soil retention. [5]

Terracing is the practice of creating nearly level areas in a hillside area. The terraces form a series of steps each at a higher level than the previous. Terraces are protected from erosion by other soil barriers. Terraced farming is more common on small farms.

Keyline design is the enhancement of contour farming, where the total watershed properties are taken into account in forming the contour lines.

Tree, shrubs and ground-cover are effective perimeter treatment for soil erosion prevention, by impeding surface flows. A special form of this perimeter or inter-row treatment is the use of a "grass way" that both channels and dissipates runoff through surface friction, impeding surface runoff and encouraging infiltration of the slowed surface water. [6]

Windbreaks are sufficiently dense rows of trees at the windward exposure of an agricultural field subject to wind erosion. [7] Evergreen species provide year-round protection however, as long as foliage is present in the seasons of bare soil surfaces, the effect of deciduous trees may be adequate.

Cover crops such as legumes plant, white turnips, radishes and other species are rotated with cash crops to blanket the soil year-round and act as green manure that replenishes nitrogen and other critical nutrients. Cover crops also help suppress weeds. [8]

Soil-conservation farming involves no-till farming, "green manures" and other soil-enhancing practices which make it hard for the soils to be equalized. Such farming methods attempt to mimic the biology of barren lands. They can revive damaged soil, minimize erosion, encourage plant growth, eliminate the use of nitrogen fertilizer or fungicide, produce above-average yields and protect crops during droughts or flooding. The result is less labor and lower costs that increase farmers’ profits. No-till farming and cover crops act as sinks for nitrogen and other nutrients. This increases the amount of soil organic matter. [8]

Repeated plowing/tilling degrades soil, killing its beneficial fungi and earthworms. Once damaged, soil may take multiple seasons to fully recover, even in optimal circumstances. [8]

Critics argue that no-till and related methods are impractical and too expensive for many growers, partly because it requires new equipment. They cite advantages for conventional tilling depending on the geography, crops and soil conditions. Some farmers claimed that no-till complicates pest control, delays planting and that post-harvest residues, especially for corn, are hard to manage. [8]

Salinity in soil is caused by irrigating with salty water. Water then evaporates from the soil leaving the salt behind. Salt breaks down the soil structure, causing infertility and reduced growth.

The ions responsible for salination are: sodium (Na + ), potassium (K + ), calcium (Ca 2+ ), magnesium (Mg 2+ ) and chlorine (Cl − ). Salinity is estimated to affect about one third of the earth's arable land. [9] Soil salinity adversely affects crop metabolism and erosion usually follows.

Salinity occurs on drylands from overirrigation and in areas with shallow saline water tables. Over-irrigation deposits salts in upper soil layers as a byproduct of soil infiltration irrigation merely increases the rate of salt deposition. The best-known case of shallow saline water table capillary action occurred in Egypt after the 1970 construction of the Aswan Dam. The change in the groundwater level led to high salt concentrations in the water table. The continuous high level of the water table led to soil salination.

Use of humic acids may prevent excess salination, especially given excessive irrigation. [ citation needed ] Humic acids can fix both anions and cations and eliminate them from root zones. [ citation needed ]

Planting species that can tolerate saline conditions can be used to lower water tables and thus reduce the rate of capillary and evaporative enrichment of surface salts. Salt-tolerant plants include saltbush, a plant found in much of North America and in the Mediterranean regions of Europe.

When worms excrete feces in the form of casts, a balanced selection of minerals and plant nutrients is made into a form accessible for root uptake. Earthworm casts are five times richer in available nitrogen, seven times richer in available phosphates and eleven times richer in available potash than the surrounding upper 150 millimetres (5.9 in) of soil. The weight of casts produced may be greater than 4.5 kg per worm per year. By burrowing, the earthworm improves soil porosity, creating channels that enhance the processes of aeration and drainage. [10]

Other important soil organisms include nematodes, mycorrhiza and bacteria. A quarter of all the animal species live underground. According to the 2020 Food and Agriculture Organization’s report "State of knowledge of soil biodiversity – Status, challenges and potentialities", there are major gaps in knowledge about biodiversity in soils. [11] [12]

Degraded soil requires synthetic fertilizer to produce high yields. Lacking structure increases erosion and carries nitrogen and other pollutants into rivers and streams. [8]

Each one percent increase in soil organic matter helps soil hold 20,000 gallons more water per acre. [8]

To allow plants full realization of their phytonutrient potential, active mineralization of the soil is sometimes undertaken. This can involve adding crushed rock or chemical soil supplements. In either case the purpose is to combat mineral depletion. A broad range of minerals can be used, including common substances such as phosphorus and more exotic substances such as zinc and selenium. Extensive research examines the phase transitions of minerals in soil with aqueous contact. [13]

Flooding can bring significant sediments to an alluvial plain. While this effect may not be desirable if floods endanger life or if the sediment originates from productive land, this process of addition to a floodplain is a natural process that can rejuvenate soil chemistry through mineralization.

Wildlife & Crop Production

The fertile river valley supported many types of wildlife, including elk, buffalo, bear, deer, swan, geese, turkey, beaver, and otter. In 1755 Arthur Dobbs, the Provincial Governor of North Carolina, in a letter to the Lords of the Board of Trade described this land as being "rich, level ground, free from rocks and gravels, but all a rich, dark red and some inclining to yellow, of the richest loams." Daniel Boone also made Davidson County his home in the 1750s.

In the 1800s the local economy was mainly agricultural, with corn, wheat, cotton, and tobacco the main crops. Wheat from the Jersey farms won first prize at the Chicago Worlds fair in 1893, and high production was then 40 to 50 bushels per acre. Tobacco from Davidson County during this same time period won first prize at the Vienna (Austria) Exposition.

In the first half of the 20th century agriculture intensified its production efforts to support the war effort. With mechanization and new varieties of seed available, crop production substantially increased from the 1950s up through the present.

Mission & History

The need for soil conservation has been recognized for centuries. Although not widely practiced in Colonial America, many farmers, including Thomas Jefferson, realized the importance of protecting topsoil. After the Dust Bowl in the 1930s and witnessing the devastating results of erosion, the U.S. Government created soil conservation districts. A political subdivision of state government, districts typically have the same boundaries as their county. Soil conservation districts provide farmers, developers and the general public with soil and water conservation expertise at the local level. The Prince George’s Soil Conservation District was established on April 7, 1941. Initially created to assist the farming community in saving valuable topsoil, the District has expanded its programs to include water quality protection, public education, urban erosion and sediment control, small pond approval, and technical assistance to urban agricultural producers, landowners, schools, federal, state and local agencies and other groups.

The mission of the Prince George’s Soil Conservation District is to protect and promote the health, safety and general welfare of the citizens of the State and County, and otherwise enhance their living environment by conservation of soil, water and related resources. The District works to control and prevent soil erosion in order to preserve natural resources, control floods, prevent impairment of dams and reservoirs, assist in maintaining the navigability of rivers and harbors, preserve wildlife, protect the tax base and public lands.

The District promotes sound land management through the development and implementation of locally-led soil conservation and water quality programs.

Watch the video: Living Soil Film (December 2022).

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