Wageningen, Netherlands
Wageningen, Netherlands
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De Souza E.,CAPES Foundation | Hengl T.,ISRIC | Kempen B.,ISRIC | Heuvelink G.B.M.,ISRIC | And 2 more authors.
GlobalSoilMap: Basis of the Global Spatial Soil Information System - Proceedings of the 1st GlobalSoilMap Conference | Year: 2014

The study aimed to evaluate and compare the prediction accuracy of two pedometric models with a conventional model for mapping the soil organic carbon and clay contents. Both pedometric models were Regression-kriging models. The difference between the two models is that one model included a conventional soil class map as covariate in addition to covariates derived from a DEM and MODIS imagery and the other model did not. The conventional mapping method was polygon- averaging. The study was carried out for the Rio Doce Basin in Brazil and the properties were predicted for four standard depths, up to 60 cm. The models were calibrated using 412 soil profile observations. The pedometric methods produced soil property maps that were as good (clay) or slightly better (carbon) than maps produced with conventional methods in the Rio Doce area and are worth further exploring for the continuation of the soil mapping program in Brazil. © 2014 Taylor & Francis Group, London, UK.

Schweers W.,Chinese Academy of Agricultural Sciences | Bai Z.,ISRIC | Campbell E.,Stanford University | Hennenberg K.,Institute of Applied Ecology | And 15 more authors.
Biomass and Bioenergy | Year: 2011

A standard methodology is needed to recognize potentially suitable areas for sustainable bioenergy crop production. This facilitates better identification of promising crops and cropping systems, logistical and economic studies, and work needed to meet regulatory criteria. A possible approach is built upon three layers of internationally available spatial data: (1) degrading and abandoned areas, (2) potentially suitable land cover classes, (3) exclusion zones such as nature reserves and areas of high biodiversity. For China, areas identified as potentially suitable range from 1.2 to 6.0% of the national territory, depending on different levels of statistical confidence in degrading area status and allowable limits of terrestrial carbon. Verification on the ground showed that about 60% of points tested conformed to the remote suitability assessment in the scenario, which represents the results for the combination of all degrading areas and a terrestrial carbon stock limit of 200 t ha-1. A top-down approach is useful in framing potentially suitable locations, but a complementary bottom-up analysis is still required to ultimately identify areas for sustainable bio-fuel production. © 2011 Elsevier Ltd.

Chandran P.,Regional Center | Tiwary P.,Regional Center | Bhattacharyya T.,Regional Center | Mandal C.,Regional Center | And 83 more authors.
Current Science | Year: 2014

Soil information system in SOTER (soil and terrain digital database) framework is developed for the Indo- Gangetic Plains (IGP) and black soil regions (BSR) of India with the help of information from 842 georeferenced soil profiles including morphological, physical and chemical properties of soils in addition to the site characteristics and climatic information. The database has information from 82 climatic stations that can be linked with the other datasets. The information from this organized database can be easily retrieved for use and is compatible with the global database. The database can be updated with recent and relevant data as and when they are available. The database has many applications such as inputs for refinement of agroecological regions and sub-regions, studies on carbon sequestration, land evaluation and land (crop) planning, soil erosion, soil quality, carbon and crop modelling and other climate change related research. This warehouse of information in a structured framework can be used as a data bank for posterity.

Van Apeldoorn D.F.,Wageningen University | Kempen B.,ISRIC | Sonneveld M.P.W.,Wageningen University | Kok K.,Wageningen University
Agriculture, Ecosystems and Environment | Year: 2013

The intensification of agricultural production strongly affects the characteristics of traditional rural landscapes. Yet, the complexity of these landscapes also puts constraints on intensification. This interrelationship leads to the hypothesis that the degree of intensification and locality are interdependent. Feedbacks between landscape and intensification often go unnoticed, while such a coupling would argue for spatial explicit studies with a co-evolutionary perspective. In this study, we localized and quantified interactions between landscape patterns and agricultural intensification for dairy farming systems in a traditional Dutch rural landscape. First, a conceptual diagram was made that maps causal interactions between landscape patterns and production intensity. This conceptual diagram was converted to spatial explicit descriptors of landscape patterns, such as hedge density, field size, clay content, ground water hydrology and spatial explicit descriptors of management such as hedgerow change, field aggregation, field grazing days and fertilizer application. Next, these landscape patterns and management descriptors were linked to the current production intensity of farms such as total farm milk yield, milk yield per cow and milk yield per hectare. These descriptors were tested for interrelations by applying two-sample Kolmogorov-Smirnov tests. We found that a higher milk production was significantly linked to larger fields, fewer hedgerows, fewer grazing days, higher use of N-fertilizer and a decrease of nutrient cycling. Furthermore, production intensity was found to differ with the landscape pattern of clay content and groundwater hydrology. On top of this landscape template, man-made patterns of field sizes and hedgerows from before 1930 are still visible in the current differences of milk production intensity. Current farm management was found to have relations with the hedgerows, field size, clay content and groundwater hydrology. These relations hint at a co-evolution of landscape pattern and agricultural intensification. Interestingly, the largest differences between descriptors of landscape pattern and intensity were found for similar values of clay content, groundwater hydrology and fertilizer use. We speculate that these similar values indicate the existence of tipping points for diverging trajectories of intensification. Identification of such tipping points has implications for policies that deal with the future dynamics of rural landscapes. © 2013.

Minasny B.,University of Sydney | Hartemink A.E.,ISRIC
Earth-Science Reviews | Year: 2011

It is practically impossible to measure soil properties continuously at each location across the globe. Therefore, it is necessary to have robust systems that can predict soil properties at a given location. That is needed in many tropical countries where the dearth of soil property measurements is large. This paper reviews the use of pedotransfer functions (PTF) for predicting properties of soils in the tropics. First, the guiding principles of prediction and the type of predictors are discussed, including laboratory data, field description and soil morphology, electromagnetic spectrum, proximal and remote sensed data. In the subsequent section, PTFs are discussed for soil physical and chemical properties followed by infrared spectroscopy, proximal sensing and remote sensing. An analysis of ISRIC (mainly tropical) and USDA (mainly temperate) soil databases showed that soils in the tropics have higher clay content, lower cation exchange capacity, higher bulk density, lower water content at - 10 kPa and - 1500 kPa than soils in the temperate regions. Various methods developed in temperate regions can be applied for the soils in the tropical regions although calibration and careful selection of predictors remains necessary. It is concluded that PTFs are an important tool to overcome the dearth of soil data in many tropical countries. © 2011 Elsevier B.V.

Li S.,University of Manitoba | MacMillan R.A.,ISRIC | Lobb D.A.,University of Manitoba | McConkey B.G.,Agriculture and Agri Food Canada | And 2 more authors.
Geomorphology | Year: 2011

Topographic depressions are abundant in topographically complex landscapes. A common practice with earlier, low resolution Digital Elevation Models (DEMs) was to remove all depressions to ensure that water flowed continuously to the edge of the DEM domain. The assumption was that most depressions were created due to errors in the DEMs. This practice is no longer justified with the increasing availability of high accuracy DEMs. However, very few studies have addressed how DEM processing options such as smoothing and coarsening and setting area and depth thresholds can affect depression identification.In this study, a site located in the Prairie Region of Canada was examined. The site is a hummocky glaciated landscape with many in-field wetlands. Lidar topographic data were collected and were used to generate a 1. m by 1. m square-grid DEM. Detailed error analyses of the lidar DEM were conducted. A set of DEMs were generated after different degrees of smoothing and coarsening. FlowMapR, an established terrain analysis tool, was used to identify depressions in each DEM with various user-defined area and depth thresholds. The results were validated against a field wetland survey.We determined that the problems associated with depression identification using a lidar DEM are two-fold. On one hand, artefactual depressions created due to DEM errors need to be eliminated, for which the raw lidar DEM need to be smoothed. On the other hand, it is also desirable to remove those topographic depressions that do not function as closed basins at the spatial or temporal scale of the processes of interest. Setting area and depth thresholds appeared to be the preferred choice for this. We suggested using the un-autocorrelated lidar DEM error as the criterion for DEM smoothing and considering depression connections in the selection of area and depth thresholds. Using lidar data on a hummocky landscape with loamy soils in the Prairie Region of Canada, 10 to 20 times smoothing operations with an area threshold of 200m2 and a depth threshold of 0.1m were recommended as guidelines for depression identification. © 2011 Elsevier B.V.

Ugbaje S.U.,Ahmadu Bello University | Reuter H.I.,ISRIC
GlobalSoilMap: Basis of the Global Spatial Soil Information System - Proceedings of the 1st GlobalSoilMap Conference | Year: 2014

Information on the spatial distribution of soil Available Water Capacity (AWC) at the regional or national scale is important for sustainable land management. This paper demonstrates an approach for mapping AWC in Nigeria at fine resolution using soil legacy data compiled from different soil surveys. The approach combines digital soil mapping techniques, regression tree modeling approach and pedotransfer functions for AWC estimation. AWC was mapped at the standard depth intervals of project. Mean AWC (cm cm -1) estimates for Nigeria from Hodnett and Tomasella (PTF-HT), Zacharias and Wessolek (PTF-ZW) and Minasny and Hartemink (PTF-MH) PTFs were 0.08, 0.21 and 0.12 cm cm-1 for the 0-5 cm depth interval and 0.16, 0.08 and 0.08 for the cumulative depth (0-200 cm). Comparison of the estimated AWC with published results for a few discreet points and locations appears very promising. The derived AWC maps using the approach from this study should provide detailed and better information for Nigeria than the currently available global AWC maps. © 2014 Taylor & Francis Group, London, UK.

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