Digital soil mapping

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Digital soil mapping (DSM) in soil science, also referred to as predictive soil mapping [1] or pedometric mapping, is the computer-assisted production of digital maps of soil types and soil properties. Soil mapping, in general, involves the creation and population of spatial soil information by the use of field and laboratory observational methods coupled with spatial and non-spatial soil inference systems.

Contents

The international Working Group on Digital Soil Mapping (WG-DSM) defines digital soil mapping as "the creation and the population of a geographically referenced soil databases generated at a given resolution by using field and laboratory observation methods coupled with environmental data through quantitative relationships." [2] [3] [4] [5]

Ambiguities

DSM can rely upon, but is considered to be distinct from traditional soil mapping, which involves manual delineation of soil boundaries by field soil scientists. Non-digital soil maps produced as result of manual delineation of soil mapping units may also be digitized or surveyors may draw boundaries using field computers, hence both traditional, knowledge-based and technology and data-driven soil mapping frameworks are in essence digital. Unlike traditional soil mapping, digital soil mapping is, however, considered to make an extensive use of:

  1. technological advances, including GPS receivers, field scanners, and remote sensing, and
  2. computational advances, including geostatistical interpolation and inference algorithms, GIS, digital elevation model, and data mining [6]

In digital soil mapping, semi-automated techniques and technologies are used to acquire, process and visualize information on soils and auxiliary information, so that the end result can be obtained at cheaper costs. Products of the data-driven or statistical soil mapping are commonly assessed for the accuracy and uncertainty and can be more easily updated when new information comes available. [6]

Digital soil mapping tries to overcome some of the drawbacks of the traditional soil maps that are often only focused on delineating soil-classes i.e. soil types. [5] Such traditional soil maps:

An example of successful digital soil mapping application is the physical properties [7] (soil texture, bulk density) developed in the European Union with around 20,000 topsoil samples of LUCAS database. [8]

Scorpan

Scorpan is a mnemonic for an empirical quantitative descriptions of relationships between soil and environmental factors with a view to using these as soil spatial prediction functions for the purpose of Digital soil mapping. It is an adaptation of Hans Jenny's five factors not for explanation of soil formation, but for empirical descriptions of relationships between soil and other spatially referenced factors. [6]

S = f(s,c,o,r,p,a,n), where

See also

Related Research Articles

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<span class="mw-page-title-main">Pedology</span> Study of soils in their natural environment

Pedology is a discipline within soil science which focuses on understanding and characterizing soil formation, evolution, and the theoretical frameworks for modeling soil bodies, often in the context of the natural environment. Pedology is often seen as one of two main branches of soil inquiry, the other being edaphology which is traditionally more agronomically oriented and focuses on how soil properties influence plant communities. In studying the fundamental phenomenology of soils, e.g. soil formation, pedologists pay particular attention to observing soil morphology and the geographic distributions of soils, and the placement of soil bodies into larger temporal and spatial contexts. In so doing, pedologists develop systems of soil classification, soil maps, and theories for characterizing temporal and spatial interrelations among soils. There are a few noteworthy sub-disciplines of pedology; namely pedometrics and soil geomorphology. Pedometrics focuses on the development of techniques for quantitative characterization of soils, especially for the purposes of mapping soil properties whereas soil geomorphology studies the interrelationships between geomorphic processes and soil formation.

<span class="mw-page-title-main">Soil erosion</span> Displacement of soil by water, wind, and lifeforms

Soil erosion is the denudation or wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, and animals. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (aeolian) erosion, zoogenic erosion and anthropogenic erosion such as tillage erosion. Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks. Soil erosion could also cause sinkholes.

<span class="mw-page-title-main">Topography</span> Study of the forms of land surfaces

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<span class="mw-page-title-main">Soil map</span>

Soil map is a geographical representation showing diversity of soil types and/or soil properties in the area of interest. It is typically the end result of a soil survey inventory, i.e. soil survey. Soil maps are most commonly used for land evaluation, spatial planning, agricultural extension, environmental protection and similar projects. Traditional soil maps typically show only general distribution of soils, accompanied by the soil survey report. Many new soil maps are derived using digital soil mapping techniques. Such maps are typically richer in context and show higher spatial detail than traditional soil maps. Soil maps produced using (geo)statistical techniques also include an estimate of the model uncertainty.

Inference is a process of deriving logical conclusion from the basis of empirical evidence and prior knowledge rather than on the basis of direct observation. Soil inference system (SINFERS) is the term proposed by McBratney et al. (2002) as a knowledge base to infer soil properties and populate the digital soil databases. SINFERS takes measurements with a given level of certainty and infers data that is not known with minimal uncertainties by means of logically linked predictive functions. These predictive functions, in a non-spatial context are referred to as pedotransfer functions. The basic assumption underlying SINFERS is that if one knows or is able to predict the basic fundamental properties of a soil, one should be able to infer all other physical and chemical properties using PTFs. Pedotransfer functions relate basic soil properties to other more difficult or expensive to measure soil properties by means of regression and various data mining tools. Crucial to the operation of SINFERS are reliable inputs, the ability to link basic soil information, and the quantification of uncertainty.

Geomorphometry, or geomorphometrics, is the science and practice of measuring the characteristics of terrain, the shape of the surface of the Earth, and the effects of this surface form on human and natural geography. It gathers various mathematical, statistical and image processing techniques that can be used to quantify morphological, hydrological, ecological and other aspects of a land surface. Common synonyms for geomorphometry are geomorphological analysis, terrain morphometry, terrain analysis, and land surface analysis. Geomorphometrics is the discipline based on the computational measures of the geometry, topography and shape of the Earth's horizons, and their temporal change. This is a major component of geographic information systems (GIS) and other software tools for spatial analysis.

The European Soil Database is the only harmonized soil database in Europe from which many other data information and services are derived. For instance, the European Soil Database v2 Raster Library contains raster (grid) data files with cell sizes of 1km x 1km for a large number of soil related parameters. Each grid is aligned with the INSPIRE reference grid. These rasters are in the public domain and allow expert users to use the data for instance to run soil-, water- and air related models.. The European Soil Database may be downloaded from the European Soil Data Center.

<span class="mw-page-title-main">Subaqueous soil</span>

Subaqueous soils are soils formed in sediment found in shallow, permanently flooded environments or soils in any areas permanently covered by water too deep for the growth of rooted plants.

Pedodiversity is the variation of soil properties within an area. Pedodiversity studies were first started by analyzing soil series–area relationships. According to Guo et al. (2003) the term pedodiversity was developed by McBratney (1992) who discussed landscape preservation strategies based on pedodiversity. Recently, examinations of pedodiversity using indices commonly used to characterize bio-diversity have been made. Ibáñez et al. (1995) first introduced ecological diversity indices as measures of pedodiversity. They include species richness, relative species abundance, and Shannon index. Richness is the number of different soil types, which is the number of soil classes at particular level in a taxonomic system. Abundance is defined as the distribution of the number of soil individuals.

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Pedometric mapping, or statistical soil mapping, is data-driven generation of soil property and class maps that is based on use of statistical methods. Its main objectives are to predict values of some soil variable at unobserved locations, and to access the uncertainty of that estimate using statistical inference i.e. statistically optimal approaches. From the application point of view, its main objective is to accurately predict response of a soil-plant ecosystem to various soil management strategies—that is, to generate maps of soil properties and soil classes that can be used for other environmental models and decision-making. It is largely based on applying geostatistics in soil science, and other statistical methods used in pedometrics.

In applied statistics and geostatistics, regression-kriging (RK) is a spatial prediction technique that combines a regression of the dependent variable on auxiliary variables with interpolation (kriging) of the regression residuals. It is mathematically equivalent to the interpolation method variously called universal kriging and kriging with external drift, where auxiliary predictors are used directly to solve the kriging weights.

Fabio Terribile is an Italian agricultural scientist and professor at the University of Naples Federico II. He is a pedologist and coordinator of the EU project Landsupport.

References

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  2. Lagacherie, P.; McBratney, A. B.; Voltz, M., eds. (2006). Digital soil mapping: an introductory perspective. Amsterdam: Elsevier. p. 600. ISBN   978-0-444-52958-9. Archived from the original on 2012-01-16. Retrieved 2012-06-19.
  3. Dobos, E.; Carré, F.; Hengl, T.; Reuter, H.I.; Tóth, G., eds. (2006). Digital Soil Mapping as a support to production of functional maps (PDF). Luxemburg: Office for Official Publications of the European Communities. p. 68. EUR 22123 EN
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