The National Cooperative Soil Survey (NCSS) has published more than 130 soil survey geographic (S... more The National Cooperative Soil Survey (NCSS) has published more than 130 soil survey geographic (SSURGO) datasets using ArcView Data Publishing (AVDP) technology during the past 10 years. Each SoilView CD-ROM provides county-level digital soil survey maps, attribute tables, supporting text, and predefined interpretive maps. The AVDP products can be readily updated and reissued with newer soil survey information as needed at relatively low cost. SoilView products are readily accessible to the general public and government users via computers running MS Windows 95 or newer operating systems. The many popular features in SoilView also enhance soil science educational programs. These same features are being considered for future development of a 2.5-dimension interactive digital soil survey.
Soil samples were collected from soil pits at depths of 0 to 5 and 5 to 10 cm and by genetic soil... more Soil samples were collected from soil pits at depths of 0 to 5 and 5 to 10 cm and by genetic soil-horizon thereafter, with data reported to 1 m depth. Weights of soil organic carbon (SOC) by profile layer were calculated using thicknesses, bulk densities, and C analyses data. Recalculation for discrete depth increments from the horizon data was necessary to statistically analyze and report the SOC for depth increments of 0 to 10, 10 to 20, 20 to 30, 30 to 60, and 60 to 100 cm. The Soil Extent Mapping Tool of the NRCS provided a snapshot, by soil survey area, of where and the size of the areas by county of the soil series sampled in this study. Estimated combined acreage of the 21 soil series, for these 30 paired native and cropped sites, was 9 Mha within 18 states. To estimate the equivalent amount of SOC represented required that the data be area-weighted and statistically analyzed. On an area-weighted basis 131,890 and 98,470 kg SOC per ha were found in the top 100 cm of the nativ...
The popular Soil Survey Geographic (SSURGO) Database is available in the Web Soil Survey, but not... more The popular Soil Survey Geographic (SSURGO) Database is available in the Web Soil Survey, but not easily used in national, regional and statewide resource planning and analysis of soils data. USDA-NRCS has added a new product designed to provide convenient access to soils information for large land areas by the simulation modeling community. The new product, called gSSURGO (g for gridded), provides detailed soil survey mapping in raster format including all traditional attributes plus “ready to map” attributes organized in statewide tiles for desktop GIS. In addition, the raster format allows GIS visualization of highly detailed soils themes for an entire state in a matter of seconds. The gSSURGO Database is derived from the official Soil Survey Geographic Database for fiscal year 2013 and was prepared by merging the traditional vector-based SSURGO digital map data and tabular data into statewide extents, adding a statewide gridded map layer derived from the vector layer, and adding...
Detailed soil data for the Conterminous United States are being made available to hydrologic mode... more Detailed soil data for the Conterminous United States are being made available to hydrologic modelers and others in a new gridded format. The Soil Survey Geographic (SSURGO) Database is now 86 percent complete for the Conterminous United States. The soil properties of interest to hydrologists include available water capacity, bulk density, saturated hydraulic conductivity, field capacity, porosity, average soil thickness, soil organic matter or carbon content, and percentages of sand, silt, clay, and rocks. The methods for creating the gridded format data summarize the attributes across soil horizons and soil components to create a value for each attribute at the mapunit level. Separate gridded products can be developed for specific depth zones, as required. The SSURGO data are being continuously improved by National Cooperative Soil Survey under the leadership of the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS). Readily accessible gridded soils data ...
ABSTRACT The U.S. Soil Survey Geographic (SSURGO) database provides detailed soil mapping for mos... more ABSTRACT The U.S. Soil Survey Geographic (SSURGO) database provides detailed soil mapping for most of the conterminous United States (CONUS). These data have been used to formulate estimates of soil carbon stocks, and have been useful for environmental models, including plant productivity models, hydrologic models, and ecological models for studies of greenhouse gas exchange. The data were compiled by the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS) from 1:24,000-scale or 1:12,000-scale maps. It was found that the total soil organic carbon stock in CONUS to 1 m depth is 57 Pg C and for the total profile is 73 Pg C, as estimated from SSURGO with data gaps filled from the 1:250,000-scale Digital General Soil Map. We explore the non-linear distribution of soil carbon on the landscape and with depth in the soil, and the implications for sampling strategies that result from the observed soil carbon variability.
ABSTRACT Prairies have been noted in several areas of Pennsylvania since the time of European set... more ABSTRACT Prairies have been noted in several areas of Pennsylvania since the time of European settlement. Because very little is known about the soils of these areas, a prairie area in northwestern Pennsylvania was studied. The A horizon of the soils of this area is thick (mean of 55 cm), and many areas have colors dark enough to qualify as mollic or umbric epipedons. The organic matter content for the top meter of the soils was greater than reported for midwestern prairie soils of similar texture and drainage and probably reflects greater plant growth and/or a lower rate of decomposition as a result of cooler and more moist climatic conditions in northwestern Pennsylvania. The average opal phytolith content for the top 15 cm of the prairie soils was 21.1 Mg ha-1. The age of these soils, estimated from phytolith accumulation, is 2000 to 6000 years. This would indicate that prairie occupation and soil formation started during the late Hypsithermal (3000 to 7000 years ago) interval. The characteristics of these soils indicate an apparent developmental continuum, extending from the midwest to Pennsylvania, of increasing organic matter accumulation and leaching under prairie vegetation. Although developed under prairie grass, these soils do not meet the base saturation classification requirements of Mollisols and would be classified as Inceptisols (Umbrepts). (C) Williams & Wilkins 1995. All Rights Reserved.
... A series of discussion papers followed a year later (Brown et al., 1982; Fischel, 1982; Fishe... more ... A series of discussion papers followed a year later (Brown et al., 1982; Fischel, 1982; Fisher, 1982; Raup, 1982; Simon and Sudman ... in other countries for regional and national land evaluation (eg, Dumanski and Stewart, 1983; Brklacich and MacDonald, 1992; Ogunkunle, 1993 ...
ABSTRACT Soil climate is the record of temporal patterns of soil moisture and temperature and is ... more ABSTRACT Soil climate is the record of temporal patterns of soil moisture and temperature and is an important component of the structure of U. S. Soil Taxonomy. The U. S. Soil Survey has used the Newhall simulation model (NSM) for estimating soil climate from atmospheric climate records at weather stations since the 1970s. The current soil climate map of the United States was published in 1994 by using NSM runs from selected weather stations along with knowledge-based hand-drawn mapping procedures. We developed a revised soil climate mapping methodology using the NSM and digital soil mapping techniques. The new methodology is called grid element Newhall simulation model (GEN), where a coordinate system is used to divide geographic space into a grid, and each element or grid-cell serves as a reference area for querying and organizing model input and for organizing and displaying model output. The GEN was used to make a soil moisture map of the conterminous United States (GEN-CONUS). The GEN-CONUS and the 1994 map were compared to each other and to two sets of weather station data from years 1961 to 1990 and years 1971 to 2000 (NCDC). Agreement between GEN-CONUS and the 1994 map was 75.6%. GEN-CONUS had higher agreement than the 1994 map with NSM output from NCDC data for 1961-1990 and 1971-2000 (k = 0.845 and 0.777). The GEN methodology was also used to generate a map of projected soil climate in the year 2080 for part of the Southern Rocky Mountains, predicting expansion of the Ustic and contraction of the Udic moisture regimes.
Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil orga... more Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (r b ), the mass of soil per unit volume. Here, we review methods used for calculating r b and assess their prevalence. We show how treatment of coarse fragments (particles >2 mm diameter) influences r b values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26%) differences in r b . Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m À2 . We suggest a revised method for accounting for coarse fractions in r b calculations. A large portion of the world's soils, particularly in drylands, are fine enough to allow r b determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.
The performance of ground-penetrating radar (GPR) in soils strongly depends on soil electrical co... more The performance of ground-penetrating radar (GPR) in soils strongly depends on soil electrical conductivity. Soils having high electrical conductivity rapidly attenuate radar energy, which restricts penetration depths and severely limits the effectiveness of GPR. Factors influencing the electrical conductivity of soils include the amount and type of salts in solution and the clay content. The Ground-Penetrating Radar Soil Suitability Map of the Conterminous United States is a thematic map showing the relative suitability of soils for GPR applications within comparatively large areas of the United States. This map is based on over twenty-five years of field observations made throughout the United States and soil attribute data contained in the State Soil Geographic (STATSGO) database. Attribute data used to determine the suitability of soils include taxonomic criteria, clay content, salinity, sodium absorption ratio, and calcium carbonate content. Based on additional testing, several GPR specific adjustments have been made. This paper describes these revisions and outlines the procedures used to develop the revised map. The revised map limits areas that are rated as being "Unsuited" for GPR to saline and sodic soils, reassesses calcareous and gypsiferous soils, and provides a mineralogy override for soils with low activity clays. This map can be used to assess the relative appropriateness of GPR for soil investigations within comparatively large areas of the conterminous United States. Published by Elsevier B.V.
In 1996, nine federal agencies with mandates to inventory and manage the nation's land, w... more In 1996, nine federal agencies with mandates to inventory and manage the nation's land, water, and biological resources signed a memorandum of understanding entitled "Developing a Spatial Framework of Ecological Units of The United States." This spatial framework is the basis for interagency coordination and collaboration in the development of ecosystem management strategies. One of the objectives in this memorandum is the development of a map of common ecological regions for the conterminous United States. The regions defined in the spatial framework will be areas within which biotic, abiotic, terrestrial, and aquatic capacities and potentials are similar. The agencies agreed to begin by exploring areas of agreement and disagreement in three federal natural-resource spatial frameworks--Major Land Resource Areas of the US Department of Agriculture (USDA) Natural Resources Conservation Service, National Hierarchy of Ecological Units of the USDA Forest Service, and Level III Ecoregions of the US Environmental Protection Agency. The explicit intention is that the framework will foster an ecological understanding of the landscape, rather than an understanding based on a single resource, single discipline, or single agency perspective. This paper describes the origin, capabilities, and limitations of three major federal agency frameworks and suggests why a common ecological framework is desirable. The scientific and programmatic benefits of common ecological regions are described, and a proposed process for development of the common framework is presented.
International Journal of Geographical Information Science, 2003
ABSTRACT Growing concerns about global climate change, biodiversity maintenance, natural resource... more ABSTRACT Growing concerns about global climate change, biodiversity maintenance, natural resources conservation, and long-term ecosystem sustainability have been responsible for the transformation of traditional single resource management approaches into integrated ecosystem management models. Eco-regions are large ecosystems of regional extent that contain smaller ecosystems of similar response potential and resource production capabilities. They can be used as a geographical framework for organizing and reporting resource information, setting bioecological recovery criteria, extrapolating site-level management, and monitoring global change. The objective of this research is to develop a quantitative, multivariate regionalization model that is capable of delineating eco-regions at multiple levels from remotely sensed information and other environmental and natural resources spatial data. The Spatial Pattern Analysis Model developed in this study uses a region-growing algorithm to generate spatially contiguous regions from primitive polygonal land units. The algorithm merges the most similar pair of neighbouring units at each iteration, based on satisfying certain similarity criteria until all units are grouped into one. This model was utilized to develop an eco-region map of Nebraska with three hierarchical levels. In the mapping process, the STATSGO data set was used to build the primitive map units. Environmental parameters included in the model were multi-temporal AVHRR data, soil rooting depth, organic matter content, available water capacity, and long-term annual averages of water balance and growing degree day totals. Development of the model provides a new and useful approach to eco-region mapping for resource managers and researchers. The method is automated and efficient, reduces the judgement biases and uncertainty of manual analyses, and can be replicated for other regions or for the regionalization of other themes.
The National Cooperative Soil Survey (NCSS) has published more than 130 soil survey geographic (S... more The National Cooperative Soil Survey (NCSS) has published more than 130 soil survey geographic (SSURGO) datasets using ArcView Data Publishing (AVDP) technology during the past 10 years. Each SoilView CD-ROM provides county-level digital soil survey maps, attribute tables, supporting text, and predefined interpretive maps. The AVDP products can be readily updated and reissued with newer soil survey information as needed at relatively low cost. SoilView products are readily accessible to the general public and government users via computers running MS Windows 95 or newer operating systems. The many popular features in SoilView also enhance soil science educational programs. These same features are being considered for future development of a 2.5-dimension interactive digital soil survey.
Soil samples were collected from soil pits at depths of 0 to 5 and 5 to 10 cm and by genetic soil... more Soil samples were collected from soil pits at depths of 0 to 5 and 5 to 10 cm and by genetic soil-horizon thereafter, with data reported to 1 m depth. Weights of soil organic carbon (SOC) by profile layer were calculated using thicknesses, bulk densities, and C analyses data. Recalculation for discrete depth increments from the horizon data was necessary to statistically analyze and report the SOC for depth increments of 0 to 10, 10 to 20, 20 to 30, 30 to 60, and 60 to 100 cm. The Soil Extent Mapping Tool of the NRCS provided a snapshot, by soil survey area, of where and the size of the areas by county of the soil series sampled in this study. Estimated combined acreage of the 21 soil series, for these 30 paired native and cropped sites, was 9 Mha within 18 states. To estimate the equivalent amount of SOC represented required that the data be area-weighted and statistically analyzed. On an area-weighted basis 131,890 and 98,470 kg SOC per ha were found in the top 100 cm of the nativ...
The popular Soil Survey Geographic (SSURGO) Database is available in the Web Soil Survey, but not... more The popular Soil Survey Geographic (SSURGO) Database is available in the Web Soil Survey, but not easily used in national, regional and statewide resource planning and analysis of soils data. USDA-NRCS has added a new product designed to provide convenient access to soils information for large land areas by the simulation modeling community. The new product, called gSSURGO (g for gridded), provides detailed soil survey mapping in raster format including all traditional attributes plus “ready to map” attributes organized in statewide tiles for desktop GIS. In addition, the raster format allows GIS visualization of highly detailed soils themes for an entire state in a matter of seconds. The gSSURGO Database is derived from the official Soil Survey Geographic Database for fiscal year 2013 and was prepared by merging the traditional vector-based SSURGO digital map data and tabular data into statewide extents, adding a statewide gridded map layer derived from the vector layer, and adding...
Detailed soil data for the Conterminous United States are being made available to hydrologic mode... more Detailed soil data for the Conterminous United States are being made available to hydrologic modelers and others in a new gridded format. The Soil Survey Geographic (SSURGO) Database is now 86 percent complete for the Conterminous United States. The soil properties of interest to hydrologists include available water capacity, bulk density, saturated hydraulic conductivity, field capacity, porosity, average soil thickness, soil organic matter or carbon content, and percentages of sand, silt, clay, and rocks. The methods for creating the gridded format data summarize the attributes across soil horizons and soil components to create a value for each attribute at the mapunit level. Separate gridded products can be developed for specific depth zones, as required. The SSURGO data are being continuously improved by National Cooperative Soil Survey under the leadership of the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS). Readily accessible gridded soils data ...
ABSTRACT The U.S. Soil Survey Geographic (SSURGO) database provides detailed soil mapping for mos... more ABSTRACT The U.S. Soil Survey Geographic (SSURGO) database provides detailed soil mapping for most of the conterminous United States (CONUS). These data have been used to formulate estimates of soil carbon stocks, and have been useful for environmental models, including plant productivity models, hydrologic models, and ecological models for studies of greenhouse gas exchange. The data were compiled by the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS) from 1:24,000-scale or 1:12,000-scale maps. It was found that the total soil organic carbon stock in CONUS to 1 m depth is 57 Pg C and for the total profile is 73 Pg C, as estimated from SSURGO with data gaps filled from the 1:250,000-scale Digital General Soil Map. We explore the non-linear distribution of soil carbon on the landscape and with depth in the soil, and the implications for sampling strategies that result from the observed soil carbon variability.
ABSTRACT Prairies have been noted in several areas of Pennsylvania since the time of European set... more ABSTRACT Prairies have been noted in several areas of Pennsylvania since the time of European settlement. Because very little is known about the soils of these areas, a prairie area in northwestern Pennsylvania was studied. The A horizon of the soils of this area is thick (mean of 55 cm), and many areas have colors dark enough to qualify as mollic or umbric epipedons. The organic matter content for the top meter of the soils was greater than reported for midwestern prairie soils of similar texture and drainage and probably reflects greater plant growth and/or a lower rate of decomposition as a result of cooler and more moist climatic conditions in northwestern Pennsylvania. The average opal phytolith content for the top 15 cm of the prairie soils was 21.1 Mg ha-1. The age of these soils, estimated from phytolith accumulation, is 2000 to 6000 years. This would indicate that prairie occupation and soil formation started during the late Hypsithermal (3000 to 7000 years ago) interval. The characteristics of these soils indicate an apparent developmental continuum, extending from the midwest to Pennsylvania, of increasing organic matter accumulation and leaching under prairie vegetation. Although developed under prairie grass, these soils do not meet the base saturation classification requirements of Mollisols and would be classified as Inceptisols (Umbrepts). (C) Williams & Wilkins 1995. All Rights Reserved.
... A series of discussion papers followed a year later (Brown et al., 1982; Fischel, 1982; Fishe... more ... A series of discussion papers followed a year later (Brown et al., 1982; Fischel, 1982; Fisher, 1982; Raup, 1982; Simon and Sudman ... in other countries for regional and national land evaluation (eg, Dumanski and Stewart, 1983; Brklacich and MacDonald, 1992; Ogunkunle, 1993 ...
ABSTRACT Soil climate is the record of temporal patterns of soil moisture and temperature and is ... more ABSTRACT Soil climate is the record of temporal patterns of soil moisture and temperature and is an important component of the structure of U. S. Soil Taxonomy. The U. S. Soil Survey has used the Newhall simulation model (NSM) for estimating soil climate from atmospheric climate records at weather stations since the 1970s. The current soil climate map of the United States was published in 1994 by using NSM runs from selected weather stations along with knowledge-based hand-drawn mapping procedures. We developed a revised soil climate mapping methodology using the NSM and digital soil mapping techniques. The new methodology is called grid element Newhall simulation model (GEN), where a coordinate system is used to divide geographic space into a grid, and each element or grid-cell serves as a reference area for querying and organizing model input and for organizing and displaying model output. The GEN was used to make a soil moisture map of the conterminous United States (GEN-CONUS). The GEN-CONUS and the 1994 map were compared to each other and to two sets of weather station data from years 1961 to 1990 and years 1971 to 2000 (NCDC). Agreement between GEN-CONUS and the 1994 map was 75.6%. GEN-CONUS had higher agreement than the 1994 map with NSM output from NCDC data for 1961-1990 and 1971-2000 (k = 0.845 and 0.777). The GEN methodology was also used to generate a map of projected soil climate in the year 2080 for part of the Southern Rocky Mountains, predicting expansion of the Ustic and contraction of the Udic moisture regimes.
Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil orga... more Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (r b ), the mass of soil per unit volume. Here, we review methods used for calculating r b and assess their prevalence. We show how treatment of coarse fragments (particles >2 mm diameter) influences r b values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26%) differences in r b . Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m À2 . We suggest a revised method for accounting for coarse fractions in r b calculations. A large portion of the world's soils, particularly in drylands, are fine enough to allow r b determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.
The performance of ground-penetrating radar (GPR) in soils strongly depends on soil electrical co... more The performance of ground-penetrating radar (GPR) in soils strongly depends on soil electrical conductivity. Soils having high electrical conductivity rapidly attenuate radar energy, which restricts penetration depths and severely limits the effectiveness of GPR. Factors influencing the electrical conductivity of soils include the amount and type of salts in solution and the clay content. The Ground-Penetrating Radar Soil Suitability Map of the Conterminous United States is a thematic map showing the relative suitability of soils for GPR applications within comparatively large areas of the United States. This map is based on over twenty-five years of field observations made throughout the United States and soil attribute data contained in the State Soil Geographic (STATSGO) database. Attribute data used to determine the suitability of soils include taxonomic criteria, clay content, salinity, sodium absorption ratio, and calcium carbonate content. Based on additional testing, several GPR specific adjustments have been made. This paper describes these revisions and outlines the procedures used to develop the revised map. The revised map limits areas that are rated as being "Unsuited" for GPR to saline and sodic soils, reassesses calcareous and gypsiferous soils, and provides a mineralogy override for soils with low activity clays. This map can be used to assess the relative appropriateness of GPR for soil investigations within comparatively large areas of the conterminous United States. Published by Elsevier B.V.
In 1996, nine federal agencies with mandates to inventory and manage the nation's land, w... more In 1996, nine federal agencies with mandates to inventory and manage the nation's land, water, and biological resources signed a memorandum of understanding entitled "Developing a Spatial Framework of Ecological Units of The United States." This spatial framework is the basis for interagency coordination and collaboration in the development of ecosystem management strategies. One of the objectives in this memorandum is the development of a map of common ecological regions for the conterminous United States. The regions defined in the spatial framework will be areas within which biotic, abiotic, terrestrial, and aquatic capacities and potentials are similar. The agencies agreed to begin by exploring areas of agreement and disagreement in three federal natural-resource spatial frameworks--Major Land Resource Areas of the US Department of Agriculture (USDA) Natural Resources Conservation Service, National Hierarchy of Ecological Units of the USDA Forest Service, and Level III Ecoregions of the US Environmental Protection Agency. The explicit intention is that the framework will foster an ecological understanding of the landscape, rather than an understanding based on a single resource, single discipline, or single agency perspective. This paper describes the origin, capabilities, and limitations of three major federal agency frameworks and suggests why a common ecological framework is desirable. The scientific and programmatic benefits of common ecological regions are described, and a proposed process for development of the common framework is presented.
International Journal of Geographical Information Science, 2003
ABSTRACT Growing concerns about global climate change, biodiversity maintenance, natural resource... more ABSTRACT Growing concerns about global climate change, biodiversity maintenance, natural resources conservation, and long-term ecosystem sustainability have been responsible for the transformation of traditional single resource management approaches into integrated ecosystem management models. Eco-regions are large ecosystems of regional extent that contain smaller ecosystems of similar response potential and resource production capabilities. They can be used as a geographical framework for organizing and reporting resource information, setting bioecological recovery criteria, extrapolating site-level management, and monitoring global change. The objective of this research is to develop a quantitative, multivariate regionalization model that is capable of delineating eco-regions at multiple levels from remotely sensed information and other environmental and natural resources spatial data. The Spatial Pattern Analysis Model developed in this study uses a region-growing algorithm to generate spatially contiguous regions from primitive polygonal land units. The algorithm merges the most similar pair of neighbouring units at each iteration, based on satisfying certain similarity criteria until all units are grouped into one. This model was utilized to develop an eco-region map of Nebraska with three hierarchical levels. In the mapping process, the STATSGO data set was used to build the primitive map units. Environmental parameters included in the model were multi-temporal AVHRR data, soil rooting depth, organic matter content, available water capacity, and long-term annual averages of water balance and growing degree day totals. Development of the model provides a new and useful approach to eco-region mapping for resource managers and researchers. The method is automated and efficient, reduces the judgement biases and uncertainty of manual analyses, and can be replicated for other regions or for the regionalization of other themes.
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Papers by Sharon Waltman