Challenges to Digital Soil Mapping
7.2 Current Progress and Application
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survey has been the incorporation into field, laboratory and reporting methods of new techniques and technologies that enhance soil scientists’ abilities to map and interpret soils and to deliver information to soil survey users.
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Fig. 7.2 Individual soil mapping units as portrayed in the Soil Survey of Barbour County, Alabama (Trayvick, 1995) (See also Plate 5 in the Colour Plate Section)
mapped soil in the soil survey legend. The mapping unit may be an individual soil series, a phase of a soil series or a combination of soils identified at the series or other taxonomic level. The map unit is a collection of polygons that represents soils as similar as possible at the mapping scale.
This paper “hard copy” of the modern soil survey is being replaced by a digital product known as SSURGO (Soil Survey Geographic Overlay). This elec-tronic soil survey data layer is being digitized from paper manuscript soil sur-veys in the United States and is available either by downloading from the Soil Data Mart http://soildatamart.nrcs.usda.gov/ or the Geospatial Data Gateway http://
datagateway.nrcs.usda.gov/NextPage.asp for use in geographic information sys-tems. The SSURGO information is also in an online format from the Web Soil Sur-vey http://websoilsurSur-vey.nrcs.usda.gov/app/. All completed soil surSur-veys digitized to the SSURGO standards and specifications are available through this website.
Fig. 7.3 is an example of a digitized soil survey from the Web Soil Survey.
Although costs for generating SSURGO are not fully documented at this time, digitizing to produce SSURGO certified databases will cost in excess of $100M
Fig. 7.3 Portion of the Dane County, Wisconsin soil survey (Glocker and Patzer, 1978) produced from the Web Soil Survey (See also Plate 6 in the Colour Plate Section)
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Fig. 7.4 Status of SSURGO digitizing in the United States. (approximately 1:2,000,000) (See also Plate 7 in the Colour Plate Section)
to fully complete all counties in the United States that have modern soil surveys.
Figure 7.4 is a map of the status of SSURGO digitizing projects. Counties colored green are completed.
Information from the previously discussed examples of the modern soil survey database has been applied, used and become institutionalized as the foundation for many county, state, federal and private programs. The generated data and informa-tion is being used for environmental regulainforma-tions, guidelines, laws and soil interpre-tations.
The Farm Security and Rural Investment Act of 2002 is landmark legislation for conservation funding and for focusing on environmental issues (Farm Bill Conser-vation Provisions, 2006). The United States Department of Agriculture Farm Bill programs depend directly on soil survey information for eligibility and administra-tion of a variety of programs including the specific programs listed in Table 7.1.
The newest of these farm bill programs, the Conservation Security Program (CSP), has been in effect since fiscal year 2003. Through fiscal year 2005, CSP has funded $181M of conservation payments. The US Congress will cap total expendi-tures for CSP at $6.037 billion (between FY-2005 and FY-2014) (Why a Watershed Approach Is Being Used, 2006).
Soil survey information from traditional soil survey products has been used as background data for tax assessment and evaluation. The state of Iowa uses soil sur-vey information for agricultural land assessment and valuation. In counties or town-ships in which field work on a modern soil survey has been completed since January 1, 1949, the assessor places emphasis upon the results of the survey in spreading the valuation among individual parcels of such agricultural property (Code of Iowa).
The state of Iowa also uses soil survey or derived data for other assessments.
Corn Suitability Ratings (CSR) is an index procedure developed in Iowa to rate
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Table 7.1 Federal programs that rely on or utilize soil survey information for planning and re-source allocation
Program Costs Contracts Acres
Agricultural Management Assistance (AMA)-provides cost-share and incentive payments to agricultural producers to voluntarily address issues, such as water management, water quality and erosion control by incorporating conservation practices into their farming operations
$23.4M 1899 392,000
The Conservation Security Program (CSP)-voluntary conservation program that supports ongoing stewardship of private agricultural lands by providing payments for maintaining and enhancing natural resources.
$181M 14975 12.1M
The Environmental Quality Incentives Program (EQIP)-voluntary program that provides assistance to farmers and ranchers who face threats to soil, water, air and related natural resources on their land
$1.08B 117,625 51.5M
The Farm and Ranch Lands Protection Program (FRPP)-voluntary program that helps farmers and ranchers keep their land in agriculture
$321M 2080 367,510
The Conservation Reserve Program (CRP)-voluntary program that grants annual rental payments for set-aside highly erodible land
$1.66B 34.7M 665,101M
The Grassland Reserve Program (GRP)-voluntary program that helps landowners and operators restore and protect grassland, including rangeland, pastureland, shrubland and other certain lands, while maintaining areas as grazing lands.
$111M 908,400 3.036M
The Wetlands Reserve Program (WRP)-voluntary program that provides technical and financial assistance to eligible landowners to address wetland, wildlife habitat, soil, water, and related natural resource concerns on private lands in an environmentally beneficial and cost effective manner.
$759M 544860 3.013M
each soil for its potential row-crop productivity. An annual conservation and land preservation tax is imposed on each acre of agricultural land that is converted to a commercial, industrial, or residential use on or after the effective date of this law. The tax rate is based on the CSR of each acre of the converted agricultural land. If the CSR of the acre is less than fifty, no tax is imposed on that acre.
If the CSR of the acre is fifty or higher, the tax is fifty dollars plus one dollar for each whole rating unit in excess of fifty. Soil survey information for this and other interpretations, including smart growth, land evaluations, site assessments and regional planning, is an indispensable tool for environmental planning in many communities.
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