The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Budiman Minasny - One of the best experts on this subject based on the ideXlab platform.

  • More Data or a Better Model? Figuring Out What Matters Most for the Spatial Prediction of Soil Carbon
    Soil Science Society of America Journal, 2017
    Co-Authors: Pallegedara D. S. N. Somarathna, Budiman Minasny, Brendan P Malone
    Abstract:

    Modeling techniques used in digital soil carbon mapping encompass a variety of algorithms to address spatial prediction problems such as spatial non-stationarity, nonlinearity and multi-colinearity. A given study site can inherit one or more such spatial prediction problems, necessitating the use of a combination of statistical learning algorithms to improve the accuracy of predictions. In addition, the training sample size may affect the accuracy of the model predictions. The effect of varying sample size on model accuracy has not been widely studied in Pedometrics. To help fill this gap, we examined the behavior of multiple linear regression (MLR), geographically weighted regression (GWR), linear mixed models (LMMs), Cubist regression trees, quantile regression forests (QRFs), and extreme learning machine regression (ELMR) under varying sample sizes. The results showed that for the study site in the Hunter Valley, Australia, the accuracy of spatial prediction of soil carbon is more sensitive to training sample size compared to the model type used. The prediction accuracy initially increases exponentially with increasing sample size, eventually reaching a plateau. Different models reach their maximum predictive potential at different sample sizes. Furthermore, the uncertainty of model predictions decreases with increasing training sample sizes.

  • the newsletter of the Pedometrics commission of the iuss πeδometron πeδometron
    2014
    Co-Authors: Budiman Minasny
    Abstract:

    It has been a big year for soil scientists and the IUSS. We had the 20th World Congress of Soil Science in Jeju, and the Pedometrics commission organised 2 successful sessions: Validation of Soil Carbon Sequestration, and Quantification and Application of Uncertainty in Pedometrics. In this meeting, A -Xing also formally handed the Chair and Vice-Chair positions to me and Yang Lin. Thanks to A -Xing and Dick Brus for taking care the Commission for the past 2 years. We also congratulate Gerard Heuvelink for being awarded the Richard Webster Medal. We can proudly celebrate our successes, the Pedometrics Commission has many activities: we have the annual Best Paper Award (please don’t forget to vote), the Richard Webster Award, and Pedometron – the biannual newsletter. We now also sent out a regular Pedometrics News to keep the communication “alive”. Next year is the International year of Soil, and we need to be more active, not only to the soil science community but also promoting soil science to the public. We will have our biennial Pedometrics conference in Cordoba Spain. And for the community, Ana Horta from Charles Sturt University, Australia, has proposed “The soil in my backyard” as an activity for the Pedometrics Commission. The idea is to introduce kindergarten and primary school students (ages 5 - 10) to Soil by engaging them in an outdoor activity. The soil activity with the kids will then be recorded and uploaded to our website, together with a Google Earth location to map our junior "soil scientists". Ana is currently forming a project description and every member of the Pedometrics board would be responsible to disseminate this project. I invite all of you to take this challenge! Alongside these achievements, we also need to think about the scientific direction of Pedometrics. Geostatistics in now a common tool and already a general subject taught at an undergraduate level, and digital soil mapping

  • Pedometrics research in the vadose zone review and perspectives
    Vadose Zone Journal, 2013
    Co-Authors: Budiman Minasny, B M Whelan, John Triantafilis, Alexander B. Mcbratney
    Abstract:

    Pedometrics is the application of mathematical and statistical methods for the study of the distribution and genesis of soils. Pedometrics research in the vadose zone comprises studies of the spatial and temporal dynamics of soil properties as a scientific challenge to increase our understanding of the processes at the earth’s surface. While geostatistics has been the main topic of investigation, Pedometrics in the vadose zone covers broader areas, which can be summarized in three main topics: (i) characterization of variability and prediction of variation of soil, (ii) sampling, measurement, and inferences of soil properties and processes, and (iii) dynamic spatiotemporal modeling. This review highlights some of the key common research areas for Pedometrics in the vadose zone, showing the synergy between Pedometrics and vadose zone science. A strength of Pedometrics is estimating the spatial distribution of soil properties using empirical approaches. However, Pedometrics needs to incorporate process-based knowledge, which adds the pedological and physical significance to the statistical robustness of predictions. A natural collaboration would therefore be with vadose zone scientists. Dynamic spatiotemporal modeling in a Bayesian hierarchical modeling framework provides a platform that will enhance collaboration between both disciplines. A future collaborative project can be envisaged to develop a global vadose zone model simulating fluxes and stores of soil water, solute, heat, and gas to address globally important issues.

  • Pedometrics Research in the Vadose Zone—Review and Perspectives
    Vadose Zone Journal, 2013
    Co-Authors: Budiman Minasny, John Triantafilis, Brett Whelan, Alexander B. Mcbratney
    Abstract:

    Pedometrics is the application of mathematical and statistical methods for the study of the distribution and genesis of soils. Pedometrics research in the vadose zone comprises studies of the spatial and temporal dynamics of soil properties as a scientific challenge to increase our understanding of the processes at the earth’s surface. While geostatistics has been the main topic of investigation, Pedometrics in the vadose zone covers broader areas, which can be summarized in three main topics: (i) characterization of variability and prediction of variation of soil, (ii) sampling, measurement, and inferences of soil properties and processes, and (iii) dynamic spatiotemporal modeling. This review highlights some of the key common research areas for Pedometrics in the vadose zone, showing the synergy between Pedometrics and vadose zone science. A strength of Pedometrics is estimating the spatial distribution of soil properties using empirical approaches. However, Pedometrics needs to incorporate process-based knowledge, which adds the pedological and physical significance to the statistical robustness of predictions. A natural collaboration would therefore be with vadose zone scientists. Dynamic spatiotemporal modeling in a Bayesian hierarchical modeling framework provides a platform that will enhance collaboration between both disciplines. A future collaborative project can be envisaged to develop a global vadose zone model simulating fluxes and stores of soil water, solute, heat, and gas to address globally important issues.

  • Spatial Scaling for Digital Soil Mapping
    Soil Science Society of America Journal, 2013
    Co-Authors: Brendan P Malone, Alex B Mcbratney, Budiman Minasny
    Abstract:

    We describe in this paper, a broad overview of spatial scale concepts and scaling procedures that are specifically relevant for digital soil mapping (DSM). Despite the recent growth and operational status of DSM, one existing and foreseeably growing issue for users of digital soil information is the inequality of spatial scales between what is required and what is actually available to adequately address soil-related questions posed from within and from outside the soil science community. In the absence of conducting new soil survey or not being able to acquire the original legacy soil information (soil point data) as a means of creating user-specified soil information products, spatial scaling provides a useful solution. Spatial scaling for DSM involves changes in map extent, grid-cell resolution, and prediction support. We review in this paper the different forms of spatial scaling, which are described in terms of changes to grid spacing and prediction support. Fine-gridding and coarse-gridding are operations where the grid spacing changes but support remains unchanged. Deconvolution and convolution are operations where the support always changes which may or may not involve changing the grid spacing. While disseveration and conflation operations occur when the support and grid size are equal and both are then changed equally and simultaneously. Some possible and existing pedometric methods are described for implementation of each scaling process, as is an extended example for performing convolution where the support changes yet the resolution remains the same.

Alexander B. Mcbratney - One of the best experts on this subject based on the ideXlab platform.

  • Pedometrics research in the vadose zone review and perspectives
    Vadose Zone Journal, 2013
    Co-Authors: Budiman Minasny, B M Whelan, John Triantafilis, Alexander B. Mcbratney
    Abstract:

    Pedometrics is the application of mathematical and statistical methods for the study of the distribution and genesis of soils. Pedometrics research in the vadose zone comprises studies of the spatial and temporal dynamics of soil properties as a scientific challenge to increase our understanding of the processes at the earth’s surface. While geostatistics has been the main topic of investigation, Pedometrics in the vadose zone covers broader areas, which can be summarized in three main topics: (i) characterization of variability and prediction of variation of soil, (ii) sampling, measurement, and inferences of soil properties and processes, and (iii) dynamic spatiotemporal modeling. This review highlights some of the key common research areas for Pedometrics in the vadose zone, showing the synergy between Pedometrics and vadose zone science. A strength of Pedometrics is estimating the spatial distribution of soil properties using empirical approaches. However, Pedometrics needs to incorporate process-based knowledge, which adds the pedological and physical significance to the statistical robustness of predictions. A natural collaboration would therefore be with vadose zone scientists. Dynamic spatiotemporal modeling in a Bayesian hierarchical modeling framework provides a platform that will enhance collaboration between both disciplines. A future collaborative project can be envisaged to develop a global vadose zone model simulating fluxes and stores of soil water, solute, heat, and gas to address globally important issues.

  • Pedometrics Research in the Vadose Zone—Review and Perspectives
    Vadose Zone Journal, 2013
    Co-Authors: Budiman Minasny, John Triantafilis, Brett Whelan, Alexander B. Mcbratney
    Abstract:

    Pedometrics is the application of mathematical and statistical methods for the study of the distribution and genesis of soils. Pedometrics research in the vadose zone comprises studies of the spatial and temporal dynamics of soil properties as a scientific challenge to increase our understanding of the processes at the earth’s surface. While geostatistics has been the main topic of investigation, Pedometrics in the vadose zone covers broader areas, which can be summarized in three main topics: (i) characterization of variability and prediction of variation of soil, (ii) sampling, measurement, and inferences of soil properties and processes, and (iii) dynamic spatiotemporal modeling. This review highlights some of the key common research areas for Pedometrics in the vadose zone, showing the synergy between Pedometrics and vadose zone science. A strength of Pedometrics is estimating the spatial distribution of soil properties using empirical approaches. However, Pedometrics needs to incorporate process-based knowledge, which adds the pedological and physical significance to the statistical robustness of predictions. A natural collaboration would therefore be with vadose zone scientists. Dynamic spatiotemporal modeling in a Bayesian hierarchical modeling framework provides a platform that will enhance collaboration between both disciplines. A future collaborative project can be envisaged to develop a global vadose zone model simulating fluxes and stores of soil water, solute, heat, and gas to address globally important issues.

  • spatial prediction of soil properties using eblup with the matern covariance function
    Geoderma, 2007
    Co-Authors: Budiman Minasny, Alexander B. Mcbratney
    Abstract:

    Spatial prediction with the presence of spatially dense ancillary variables has attracted research in Pedometrics. While soil survey and analysis of soil properties are still expensive and time consuming, the secondary data can be made available on a dense grid for the whole area of interest. The main aim of using the ancillary data is to enhance prediction of soil properties by making use of the ancillary variables as covariates. Methods that can be used for this purpose are kriging with external drift, cokriging, regression kriging, and REML-EBLUP (Residual Maximum Likelihood-Empirical Best Linear Unbiased Predictor). Regression kriging is a sub-optimal method that has been utilised extensively because it is easy to use and has been shown empirically to perform as well as other methods. A statically sound method is REML-EBLUP. This paper examines the use of REML-EBLUP in combination with the Matern covariance function for spatial prediction of soil properties. Methods for estimating parameters of the Matern variogram using REML, and prediction with EBLUP are described. The prediction capability of REML-EBLUP, regression kriging, and ordinary kriging is compared for four datasets. Results show that although REML-EBLUP generally improves the prediction, the improvement is small compared with regression kriging. Thus, for practical applications regression kriging appears to be a robust method. REML-EBLUP is useful when the trend is strong, and the number of observations is small (< 200). We concluded that improvement in the prediction of soil properties does not rely on more sophisticated statistical methods, but rather on gathering more useful and higher quality data.

Alex B Mcbratney - One of the best experts on this subject based on the ideXlab platform.

  • Soil in space and time
    2020
    Co-Authors: Alfred E. Hartemink, Alex B Mcbratney, R. E. White
    Abstract:

    This four-volume set, edited by leading experts in soil science, brings together in one collection a series of papers that have been fundamental to the development of soil science as a defined discipline. Volume 1 on Soil in Space and Time covers: - Soil morphology and micromorphology - Soil geography - Soil genesis - Soil classification - Pedometrics - Paleopedology

  • Quantifying Capability: GlobalSoilMap
    Progress in Soil Science, 2020
    Co-Authors: Alex B Mcbratney, Dominique Arrouays, Lorna E. Jarrett
    Abstract:

    GlobalSoilMap is an initiative of the Digital Soil Mapping Working Groups of the International Union of Soil Sciences (IUSS, digitalsoilmapping.org. Available at http://digitalsoilmapping.org/. Accessed 22 Oct 2015). It aims to meet the needs of the modelling community, farmers, land managers, policy developers and decision-makers, by creating a fine resolution (100 × 100 m grid) quantitative digital soil map of the world, using state-of-the-art and emerging technologies such as remote sensing, data mining and spatial databases. The data will be stored in a freely available distributed system with a set of standards for Web services. The approach has three components: digital soil mapping, recommendations for soil management and providing service to end users (Sanchez et al. Science 325, 2009). The project originated in 2006 as an effort to address the unmet need for quantitative answers to questions about soil-related issues such as soil carbon sequestration, the impact of soil carbon on biomass production and the change in soil status over time. To address such questions requires information about stores and fluxes of water, carbon, nutrients and solutes, in other words, functional properties of soils. The most significant stocks and flows are water including run-off, leaching, waterlogging and water available to plants, nutrients, carbon, solutes and acidification. Access to information about soil properties reduces risks in decision-making, but in order to understand and manage these risks, estimates of uncertainties in soil properties are required. Therefore, all quantitative data in the GlobalSoilMap will have an associated uncertainty. The project is facilitated by the synthesis of pedology, which focuses on soil processes, and Pedometrics, which focuses on quantitative analyses.

  • Soil Profile Classes
    Pedometrics, 2018
    Co-Authors: Nathan P. Odgers, Alex B Mcbratney, Florence Carré
    Abstract:

    The previous chapter discussed the possibility of using pedometric techniques to make numerical classifications of soil material and soil layers. Of course it is not a step too far to use pedometric techniques to make classifications of entire profiles also. That is the subject of this chapter.

  • Pedometric Treatment of Soil Attributes
    Pedometrics, 2018
    Co-Authors: Uta Stockmann, Edward J. Jones, Inakwu O. A. Odeh, Alex B Mcbratney
    Abstract:

    There are some universally described soil attributes that are worthy of more detailed pedometric description. Here, we largely concentrate on field properties which have particular issues associated with them. We are not attempting to be exhaustive. Over the years most countries have performed field descriptions, and laboratory analysis of soil based on some kind of standard technique. The methods that can be utilized for in-situ field description were already developed in the 1950s and refined and standardised by most countries in the 1970s and 1980s. These efforts have resulted in what is referred to as soil legacy data. The aim of this chapter is to illustrate how these soil legacy data can be modified for pedometric, quantitative and in general terms more objective soil analysis. Here, we will also discuss how we can use these quantitative descriptions to perform a more quantitative analysis of soil attributes, utilizing mathematical descriptors or how we can achieve a more quantitative measurement and assessment of soil attributes utilizing new technology and computational advances.

  • Soil Material Classes
    Pedometrics, 2018
    Co-Authors: Nathan P. Odgers, Alex B Mcbratney
    Abstract:

    Soil classification is really about answering the question what makes a soil? Or, perhaps, what makes one soil different from another? To answer questions like these, soil classifiers create taxonomic rules to separate one kind of soil from another and categorise and make sense of the diverse pattern of the soil continuum. Traditionally a great deal of consideration has been given to characterising and classifying the whole soil profile in a top-down fashion. Pedometric methods allow us to answer the same questions in a bottom-up trajectory. Thus, the starting point is not the whole soil profile or even its major constituents, the soil horizons. Rather we start by classifying the actual, tangible, skeleton of soil itself: the soil material.

Jon Hempel - One of the best experts on this subject based on the ideXlab platform.

  • testing the pedometric evaluation of taxonomic units on soil taxonomy a step in advancing towards a universal soil classification system
    Geoderma, 2016
    Co-Authors: Erika Micheli, Alex B Mcbratney, Vince Lang, Phillip R Owens, Jon Hempel
    Abstract:

    Abstract Most existing soil classification systems were developed to understand and provide information on soils, their natural properties and potential use for certain purposes. The conceptual developments of the systems took place before the recent boom of observation technologies, data storage and data processing achievements that can support to determine or predict soil differences. Until the recent past soils under agricultural or forestry use received more attention than other soils, such as anthropogenically modified or urban soils, or soils of the cold regions. The broader view of soil functions and the understanding of global environmental processes require a better understanding and description of all soils. Precisely recorded and harmonized data is needed to serve the new era of modern agricultural practices, other land uses as well as different scientific applications. The soil science community is challenged to apply the accumulated knowledge on soil formation, soil differences and functions, as well as, new tools of robust data processing to evaluate current systems and define objective relationships for better future classification systems. The evaluation of existing soil classification systems may help the understanding of taxonomic relationships of differentiated soil groups and improve our methods of classifying soils. This paper is summarizing the approaches and methods of evaluation that was applied for the great group and higher levels of Soil Taxonomy. Simple statistical and pedometric methods were applied on centroids and, calculated on the basis of properties commonly used to define the classification units. The centroids provide an objective tool to evaluate the concepts of taxa and the taxonomic relationships between them. Examples of conceptual evaluations and detailed discussions of the taxonomic distance calculations between the great groups within their orders and members of other orders are provided. The presented methods and relationships were found very useful for the evaluation purpose. The extension of the methods for other systems, other data bases and the combination of those is in progress. The initial results suggest that the objective, pedometric approaches can support the development of an envisioned Universal Soil Classification System.

  • Testing the pedometric evaluation of taxonomic units on soil taxonomy — A step in advancing towards a universal soil classification system
    Geoderma, 2016
    Co-Authors: Erika Micheli, Alex B Mcbratney, Vince Lang, Phillip R Owens, Jon Hempel
    Abstract:

    Abstract Most existing soil classification systems were developed to understand and provide information on soils, their natural properties and potential use for certain purposes. The conceptual developments of the systems took place before the recent boom of observation technologies, data storage and data processing achievements that can support to determine or predict soil differences. Until the recent past soils under agricultural or forestry use received more attention than other soils, such as anthropogenically modified or urban soils, or soils of the cold regions. The broader view of soil functions and the understanding of global environmental processes require a better understanding and description of all soils. Precisely recorded and harmonized data is needed to serve the new era of modern agricultural practices, other land uses as well as different scientific applications. The soil science community is challenged to apply the accumulated knowledge on soil formation, soil differences and functions, as well as, new tools of robust data processing to evaluate current systems and define objective relationships for better future classification systems. The evaluation of existing soil classification systems may help the understanding of taxonomic relationships of differentiated soil groups and improve our methods of classifying soils. This paper is summarizing the approaches and methods of evaluation that was applied for the great group and higher levels of Soil Taxonomy. Simple statistical and pedometric methods were applied on centroids and, calculated on the basis of properties commonly used to define the classification units. The centroids provide an objective tool to evaluate the concepts of taxa and the taxonomic relationships between them. Examples of conceptual evaluations and detailed discussions of the taxonomic distance calculations between the great groups within their orders and members of other orders are provided. The presented methods and relationships were found very useful for the evaluation purpose. The extension of the methods for other systems, other data bases and the combination of those is in progress. The initial results suggest that the objective, pedometric approaches can support the development of an envisioned Universal Soil Classification System.

Erika Micheli - One of the best experts on this subject based on the ideXlab platform.

  • testing the pedometric evaluation of taxonomic units on soil taxonomy a step in advancing towards a universal soil classification system
    Geoderma, 2016
    Co-Authors: Erika Micheli, Alex B Mcbratney, Vince Lang, Phillip R Owens, Jon Hempel
    Abstract:

    Abstract Most existing soil classification systems were developed to understand and provide information on soils, their natural properties and potential use for certain purposes. The conceptual developments of the systems took place before the recent boom of observation technologies, data storage and data processing achievements that can support to determine or predict soil differences. Until the recent past soils under agricultural or forestry use received more attention than other soils, such as anthropogenically modified or urban soils, or soils of the cold regions. The broader view of soil functions and the understanding of global environmental processes require a better understanding and description of all soils. Precisely recorded and harmonized data is needed to serve the new era of modern agricultural practices, other land uses as well as different scientific applications. The soil science community is challenged to apply the accumulated knowledge on soil formation, soil differences and functions, as well as, new tools of robust data processing to evaluate current systems and define objective relationships for better future classification systems. The evaluation of existing soil classification systems may help the understanding of taxonomic relationships of differentiated soil groups and improve our methods of classifying soils. This paper is summarizing the approaches and methods of evaluation that was applied for the great group and higher levels of Soil Taxonomy. Simple statistical and pedometric methods were applied on centroids and, calculated on the basis of properties commonly used to define the classification units. The centroids provide an objective tool to evaluate the concepts of taxa and the taxonomic relationships between them. Examples of conceptual evaluations and detailed discussions of the taxonomic distance calculations between the great groups within their orders and members of other orders are provided. The presented methods and relationships were found very useful for the evaluation purpose. The extension of the methods for other systems, other data bases and the combination of those is in progress. The initial results suggest that the objective, pedometric approaches can support the development of an envisioned Universal Soil Classification System.

  • Testing the pedometric evaluation of taxonomic units on soil taxonomy — A step in advancing towards a universal soil classification system
    Geoderma, 2016
    Co-Authors: Erika Micheli, Alex B Mcbratney, Vince Lang, Phillip R Owens, Jon Hempel
    Abstract:

    Abstract Most existing soil classification systems were developed to understand and provide information on soils, their natural properties and potential use for certain purposes. The conceptual developments of the systems took place before the recent boom of observation technologies, data storage and data processing achievements that can support to determine or predict soil differences. Until the recent past soils under agricultural or forestry use received more attention than other soils, such as anthropogenically modified or urban soils, or soils of the cold regions. The broader view of soil functions and the understanding of global environmental processes require a better understanding and description of all soils. Precisely recorded and harmonized data is needed to serve the new era of modern agricultural practices, other land uses as well as different scientific applications. The soil science community is challenged to apply the accumulated knowledge on soil formation, soil differences and functions, as well as, new tools of robust data processing to evaluate current systems and define objective relationships for better future classification systems. The evaluation of existing soil classification systems may help the understanding of taxonomic relationships of differentiated soil groups and improve our methods of classifying soils. This paper is summarizing the approaches and methods of evaluation that was applied for the great group and higher levels of Soil Taxonomy. Simple statistical and pedometric methods were applied on centroids and, calculated on the basis of properties commonly used to define the classification units. The centroids provide an objective tool to evaluate the concepts of taxa and the taxonomic relationships between them. Examples of conceptual evaluations and detailed discussions of the taxonomic distance calculations between the great groups within their orders and members of other orders are provided. The presented methods and relationships were found very useful for the evaluation purpose. The extension of the methods for other systems, other data bases and the combination of those is in progress. The initial results suggest that the objective, pedometric approaches can support the development of an envisioned Universal Soil Classification System.

  • Traditional and pedometric approaches to justify the introduction of swelling clay soils as a new soil type in the modernized Hungarian Soil Classification System
    Catena, 2015
    Co-Authors: Márta Fuchs, Vince Lang, Tamás Szegi, Erika Micheli
    Abstract:

    Abstract Clay and clay loam textured soils that are mainly characterized by smectite dominated mineralogy cover about 25% of the territory of Hungary ( Stefanovits and Dombovari, 1985 ). Despite their distinctive morphology, special characteristics and widespread coverage, these soils belong to several different taxonomic units in the current genetic based Hungarian Soil Classification System (HSCS), making the differentiation and definition of several units and correlation with international standards difficult. As part of the ongoing modernization process of the HSCS, detailed documentation of high smectite clay content, shrinking and swelling soils developed on different substrates, topographical positions and geographical areas was carried out in Hungary. The collected data was correlated with the World Reference Base for Soil Resources and the dominant soil forming processes were linked to diagnostic elements. The traditional soil classification methodology was supplemented with the modern pedometric method of centroid based taxonomic distance calculation to evaluate the taxonomic relationship between the Hungarian clay soils and the WRB Reference Soil Groups. Our findings confirmed that the swelling clay soils of Hungary satisfy the morphological and measureable physical and chemical criteria of the WRB Vertisol Reference Soil Group. The centroid based taxonomic distance calculations were successfully applied for objective expression of similarities and differences between the examined soil types. The studied profiles and the applied methods justify the introduction of swelling clay soils to the highest level of the modernized Hungarian Classification System. The applied methodology can be a useful tool in evaluation, improvement or development of other soil classification systems.