Soil organic carbon (SOC) generates several ecosystem services (ES), including a regulating service by sequestering carbon (C) as SOC. This ES can be valued based on the avoided social cost of carbon (SC-CO2) from the long-term damage resulting from emissions of carbon dioxide (CO2). The objective of this study was to assess the value of SOC stocks, based on the avoided SC-CO2 ($42 per metric ton of CO2 in 2007 U.S. dollars), in the contiguous United States (U.S.) by soil order, soil depth (0–20, 20–100, 100–200 cm), land resource region (LRR), state, and region using information from the State Soil Geographic (STATSGO) database. The total calculated monetary value for SOC storage in the contiguous U.S. was between $4.64T (i.e., $4.64 trillion U.S. dollars, where T = trillion = 1012) and $23.1T, with a midpoint value of $12.7T. Soil orders with the highest midpoint SOC storage values were 1): Mollisols ($4.21T), 2) Histosols ($2.31T), and 3) Alfisols ($1.48T). The midpoint values of SOC normalized by area within soil order boundaries were ranked: 1) Histosols ($21.58 m−2), 2) Vertisols ($2.26 m−2), and 3) Mollisols ($2.08 m−2). The soil depth interval with the highest midpoint values of SOC storage and content was 20–100 cm ($6.18T and $0.84 m−2, respectively), while the depth interval 100–200 cm had the lowest midpoint values of SOC storage ($2.88T) and content ($0.39 m−2). The depth trends exemplify the prominence of SOC in the upper portions of soil. The LRRs with the highest midpoint SOC storage values were: 1) M – Central Feed Grains and Livestock Region ($1.8T), 2) T – Atlantic and Gulf Coast Lowland Forest and Crop Region ($1.26T), and 3) K – Northern Lake States Forest and Forage Region ($1.16T). The midpoint values of SOC normalized by area within LRR boundaries were ranked: 1) U – Florida Subtropical Fruit, Truck Crop, and Range Region ($6.10 m−2), 2) T – Atlantic and Gulf Coast Lowland Forest and Crop Region ($5.44 m−2), and 3) K – Northern Lake States Forest and Forage Region ($3.88 m−2). States with the highest midpoint values of SOC storage were: 1) Texas ($1.08T), 2) Minnesota ($834B) (i.e., $834 billion U.S. dollars, where B = billion = 109), and 3) Florida ($742B). Midpoint values of SOC normalized by area within state boundaries were ranked: 1) Florida ($5.44 m−2), 2) Delaware ($4.10 m−2), and 3) Minnesota ($3.99 m−2). Regions with the highest midpoint values of SOC storage were: 1) Midwest ($3.17T), 2) Southeast ($2.44T), and 3) Northern Plains ($2.35T). Midpoint values of SOC normalized by area within region boundaries were ranked: 1) Midwest ($2.73 m−2), 2) Southeast ($2.31 m−2), and 3) East ($1.82 m−2). The reported values and trends demonstrate the need for policies with regards to SOC management, which requires incentives within administrative boundaries but informed by the geographic distribution of SOC.

Soil ecosystem services (ES) (e.g., provisioning, regulation/maintenance, and cultural) and ecosystem disservices (ED) are dependent on soil diversity/pedodiversity (variability of soils), which needs to be accounted for in the economic analysis and business decision-making. The concept of pedodiversity (biotic + abiotic) is highly complex and can be broadly interpreted because it is formed from the interaction of atmospheric diversity (abiotic + biotic), biodiversity (biotic), hydrodiversity (abiotic + biotic), and lithodiversity (abiotic) within ecosphere and the anthroposphere. Pedodiversity is influenced by intrinsic (within the soil) and extrinsic (outside soil) factors, which are also relevant to ES/ED. Pedodiversity concepts and measures may need to be adapted to the ES framework and business applications. Currently, there are four main approaches to analyze pedodiversity: taxonomic (diversity of soil classes), genetic (diversity of genetic horizons), parametric (diversity of soil properties), and functional (soil behavior under different uses). The objective of this article is to illustrate the application of pedodiversity concepts and measures to value ES/ED with examples based on the contiguous United States (U.S.), its administrative units, and the systems of soil classification (e.g., U.S. Department of Agriculture (USDA) Soil Taxonomy, Soil Survey Geographic (SSURGO) Database). This study is based on a combination of original research and literature review examples. Taxonomic pedodiversity in the contiguous U.S. exhibits high soil diversity, with 11 soil orders, 65 suborders, 317 great groups, 2026 subgroups, and 19,602 series. The ranking of “soil order abundance” (area of each soil order within the U.S.) expressed as the proportion of the total area is: (1) Mollisols (27%), (2) Alfisols (17%), (3) Entisols (14%), (4) Inceptisols and Aridisols (11% each), (5) Spodosols (3%), (6) Vertisols (2%), and (7) Histosols and Andisols (1% each). Taxonomic, genetic, parametric, and functional pedodiversity are an essential context for analyzing, interpreting, and reporting ES/ED within the ES framework. Although each approach can be used separately, three of these approaches (genetic, parametric, and functional) fall within the “umbrella” of taxonomic pedodiversity, which separates soils based on properties important to potential use. Extrinsic factors play a major role in pedodiversity and should be accounted for in ES/ED valuation based on various databases (e.g., National Atmospheric Deposition Program (NADP) databases). Pedodiversity is crucial in identifying soil capacity (pedocapacity) and “hotspots” of ES/ED as part of business decision making to provide more sustainable use of soil resources. Pedodiversity is not a static construct but is highly dynamic, and various human activities (e.g., agriculture, urbanization) can lead to soil degradation and even soil extinction.

Total soil carbon (TSC) is a composite (total) stock, which is the sum of soil organic carbon (SOC) and soil inorganic carbon (SIC). Total soil carbon, and its individual two components, are all important criteria for assessing ecosytems services (ES) and for achieving United Nations (UN) Sustainable Development Goals (SDGs). The objective of this study was to assess the value of TSC stocks, based on the concept of the avoided social cost of carbon dioxide emissions, for the contiguous United States (U.S.) by soil order, soil depth (0–20, 20–100, 100–200 cm), land resource region (LRR), state, and region using information from the State Soil Geographic (STATSGO) database. The total calculated monetary value for TSC storage in the contiguous U.S. was between $8.13T (i.e., $8.13 trillion U.S. dollars, where T = trillion = 1012) and $37.5T, with a midpoint value of $21.1T. Soil orders with the highest TSC storage midpoint values were Mollisols ($7.78T) and Aridisols ($2.49T). Based on area, however, the soil orders with highest midpoint TSC values were Histosols ($21.95 m−2) and Vertisols ($5.84 m−2). Soil depth was important, with the highest values of TSC storage being found in the interval 20–100 cm ($9.87T—total midpoint value, and $1.34 m−2—midpoint area density). The soil depth interval 0–20 cm had the lowest TSC storage ($4.30T) and lowest area-density ($0.58 m−2) value, which exemplifies the prominence of TSC in the deeper subsurface layers of soil. The LRRs with the highest midpoint TSC storage values were: M—Central Feed Grains and Livestock Region ($2.82T) and D—Western Range and Irrigated Region ($2.64T), whereas on an area basis the LRRs with the highest values were I—Southwest Plateaus and Plains Range and Cotton Region ($6.90 m−2) and J—Southwestern Prairies Cotton and Forage Region ($6.38 m−2). Among the U.S. states, the highest midpoint TSC storage values were Texas ($4.03T) and Minnesota ($1.29T), while based on area this order was reversed (i.e., Minnesota: $6.16 m−2; Texas: $6.10 m−2). Comprehensive assessment of regulating ES requires TSC, which is an important measure in achieving the UN SDGs. Despite the known shortcomings of soil databases, such as their static nature and the wide ranges of uncertainty reported for various soil properties, they provide the most comprehensive information available at this time for making systematic assessments of ecosystem services at large spatial scales.

Current applications of the Ecosystems Services (ES) framework to soils are narrowly defined (e.g., soil-based, pedosphere-based, etc.), and focus on soil properties while treating soil as a closed system. Because soil is an open system, it receives and loses matter across its boundaries within Earth’s spheres (atmosphere, biosphere, hydrosphere, lithosphere, ecosphere, and anthroposphere), which also need to be accounted for in economic analysis. In market economies, the market transforms resources from the Earth’s pedosphere and related spheres into goods and services for societal welfare with non-market institutions mediating human and environmental interactions. These transformations and mediations can result not only in welfare but damages as well. The concept of soil ES and ecosystem disservices (ED) is a human-centered framework, which can be a useful tool in business decision-making. Soil ES (e.g., provisioning, regulation/ maintenance, and cultural) are used to produce goods and services, but the value of these ES and ED are not always accounted for as a part of business decision-making. The objective of this review is to illustrate the monetary valuation of ecosystem services of soil systems (SS) with examples based on the organizational hierarchy of soil systems. The organizational hierarchy of soil systems can be used in economic valuations of soil ES by scale (e.g., world, continent), time (e.g., soil, geologic), qualitative and quantitative degrees of computation (e.g., mental, verbal, descriptive, mathematical, deterministic, stochastic), and degree of complexity (e.g., mechanistic, empirical). Soil survey databases, soil analyses, Soil Data Systems (SDS), and Soil Business Systems (SBS) provide tools and a wide range of quantitative/qualitative data and information to evaluate goods and services for various business applications, but these sources of soil data may be limited in scope due to their static nature. Valuation of soil resources based on soil and non-soil science databases (e.g., National Atmospheric Deposition Program (NADP) databases, etc.) is critically needed to account for these ES/ED as part of business decision-making to provide more sustainable use of soil resources. Since most ecosystems on Earth have been modified by human activity, “soil systems goods and services” (SSGS) may be a more applicable term to describe soil contributions (benefits/damages) to economic activity, compared to a term such as “soil ecosystem goods and services.”

A "soil carbon hotspot" (SCH) is a geographic area having an abundance of soil carbon, and therefore higher ecosystem services value based on avoided social costs of CO 2 emissions. Soil organic carbon (SOC), soil inorganic carbon (SIC), and total soil carbon (TSC) are critical data to help identify SCH at the farm scale, but monetary methods of hotspot evaluation are not well defined. This study provides a first of its kind quantitative example of farm-scale monetary value of soil carbon (C), and mapping of SCH based on avoided social cost of CO 2 emissions using both Soil Survey Geographic (SSURGO) database and field measurements. The total calculated monetary value for TSC storage at the Willsboro Farm based on the SSURGO database was about 7.3 million U.S. dollars ($7.3 M), compared to $2.8 M based on field data from averaged soil core results. This difference is attributed to variation in soil sampling methodology, laboratory methods of soil C analyses, and depth of reported soil C results. Despite differences in total monetary valuation, observed trends by soil order were often similar for SSURGO versus field methods, with Alfisols typically having the highest total and area-normalized monetary values