{"type": "FeatureCollection", "features": [{"id": "10.1016/j.agee.2005.10.020", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-21T16:15:05Z", "type": "Journal Article", "created": "2006-01-11", "title": "Soil Acidification Without Ph Drop Under Intensive Cropping Systems In Northeast Thailand", "description": "Light textured sandy soils occupy significant areas of Northeast Thailand and are characterized as being acidic to depth with a low inherent fertility. These soils form the basis of agricultural production systems on which significant numbers of people depend upon for livelihoods. The objectives of this study were to investigate soil acidification following the introduction of Stylosanthes in cropping systems of a tropical semi-arid region. Most soils in Northeast Thailand are sandy and acidic (pH 4.0 in CaCl2) with high rate of drainage. Soil acidification was studied over a 6-year period on plots that had been treated either with or without lime additions under different cropping patterns. In the initial first 3 years, a rotation of maize and cowpea was compared to a bare soil treatment where no vegetation was allowed to establish. During the following 3 years, a rotation of maize and Stylosanthes was compared to a continuous Stylosanthes hamata (stylo) treatment. Total soil acidification was calculated from measured pH changes and pH buffer capacity. Acidification due to root system activity was estimated from the above ground biomass production and its ash alkalinity. In the limed systems, soil pH decrease was well correlated with the ash alkalinity of the crop and its removal from the plot. Acidification was highest in the bare soil (6.3 kmol H+ ha(-1) year(-1)), due to leaching of applied N fertilizers. The cowpea-maize rotations did not increase significantly the rate of acid addition (7.6 kmol H+ ha(-1) year(-1)), since the crop residues were returned to the plot. The introduction of stylo in the cropping system resulted in a lower net acidification rate when it was cultivated in rotation with maize (1.3 kmol H+ ha(-1) year(-1)), due to the lower rate of leaching. In contrast, continuous cultivation of stylo triggered accelerated acidification (7.2 kmol H+ ha(-1) year(-1)), as a result of the large quantities of biomass with high ash alkalinity being removed from the plot. In the no-lime system, the pH of the soil profile remained stable at pH 4.0 regardless of the cropping system, even though the acidification rates were quite similar to those in the limed treatments. This would suggest that the soil was strongly buffered at pH 4.0. XRD patterns showed that kaolinite, the main clay mineral, was more disordered and less crystalline in the surface horizons than at depth. It is suggested that the dissolution of kaolinite is responsible for the buffering of soil pH at 4.0. From the dissolution equation of kaolinite, it is expected that the amount of aluminium in the topsoil would increase along with the release silica that would accelerate cementation processes between soil particles resulting in further degradation. (c) 2005 Elsevier B.V. All rights reserved.", "keywords": ["550", "SANDY SOILS", "buffering capacity", "01 natural sciences", "630", "soil degradation", "acidification", "[SDV.EE]Life Sciences [q-bio]/Ecology", "sandy soils", "BUFFERING CAPACITY", "0105 earth and related environmental sciences", "2. Zero hunger", "kaolinite", "SOL SABLEUX", "cropping systems", "04 agricultural and veterinary sciences", "Stylosanthes", "KAOLINITE", "15. Life on land", "6. Clean water", "[SDV.EE] Life Sciences [q-bio]/Ecology", " environment", "ASH ALKALINITY", "0401 agriculture", " forestry", " and fisheries", "environment", "ash alkalinity", "STYLOSANTHES", "ACIDIFICATION"]}, "links": [{"href": "https://doi.org/10.1016/j.agee.2005.10.020"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Agriculture%2C%20Ecosystems%20%26amp%3B%20Environment", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.agee.2005.10.020", "name": "item", "description": "10.1016/j.agee.2005.10.020", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.agee.2005.10.020"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2006-06-01T00:00:00Z"}}, {"id": "10.1016/j.conbuildmat.2018.12.188", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-21T16:15:28Z", "type": "Journal Article", "created": "2019-01-07", "title": "Use of alkali activated high-calcium fly ash binder for kaolin clay soil stabilisation: Physicochemical evolution", "description": "This study addresses the use of alkali activated high-calcium fly ash-based binder to improve engineering characteristics of soft clay-rich soils as an alternative to common stabilisers. The physico-chemical reaction sequence has been investigated by considering the binder alone and the binder mixed with kaolin. An insight into the reactivity evidenced that calcium-containing phases derived from high-calcium fly ash represent the reactive phases and, hence, pozzolanic activity is the dominant process. New compounds are formed, thenardite Na2SO4 and an amorphous silicate consisting of chains combined with calcium probably incorporating three-dimensional four-fold aluminium environments.", "keywords": ["SOIL STABILISATION", "SOL", "[SPI] Engineering Sciences [physics]", "CENDRE VOLANTE", "0211 other engineering and technologies", "CENDRES VOLANTES RICHES EN CALCIUM", "KAOLIN", "02 engineering and technology", "Engineering (General). Civil engineering (General)", "Alkali activated material", "High-calcium fly ash", "620", "ALKALI ACTIVATED MATERIAL", "[SPI]Engineering Sciences [physics]", "TA", "MATERIAU", "HIGH-CALCIUM FLY ASH", "Alkali activated material; High-calcium fly ash; Kaolin; Soil stabilisation", "Soil stabilisation", "Kaolin", "MATIERE ACTIVEE PAR UN ALCALI", "STABILISATION DES SOLS"]}, "links": [{"href": "https://strathprints.strath.ac.uk/67238/1/Coudert_etal_CBM_2018_Use_of_alkali_activated_high_calcium_fly_ash_binder_for_kaolin_clay_soil_stabilisation.pdf"}, {"href": "https://doi.org/10.1016/j.conbuildmat.2018.12.188"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Construction%20and%20Building%20Materials", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.conbuildmat.2018.12.188", "name": "item", "description": "10.1016/j.conbuildmat.2018.12.188", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.conbuildmat.2018.12.188"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-03-01T00:00:00Z"}}, {"id": "10.3390/su13073732", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-21T16:19:32Z", "type": "Journal Article", "created": "2021-03-26", "title": "The Optimisation Analysis of Sand-Clay Mixtures Stabilised with Xanthan Gum Biopolymers", "description": "<p>Sand\uffe2\uff80\uff93clay mixtures can be encountered in both natural soils (e.g., residual soils, clay deposits and clinosols) and artificial fills. The method of utilising biopolymers in ground improvement for sand\uffe2\uff80\uff93clay mixtures has emerged recently. However, a full understanding of the strengthening effect of biopolymer-treated sand\uffe2\uff80\uff93clay mixtures has not yet been achieved due to a limited number of relevant studies. In this study, xanthan gum (XG), as one of the eco-friendly biopolymers, was used to treat reconstituted sand\uffe2\uff80\uff93clay mixtures that had various compositions in related to clay (or sand) content and clay type (kaolin and bentonite). A series of laboratory unconfined compression strength (UCS) tests were conducted to probe the performances of XG-treated sand\uffe2\uff80\uff93clay mixtures from two aspects, i.e., optimum treatment conditions (e.g., XG content and initial moisture content) to achieve the maximum strengthening effect and strengthening efficiency for the sand\uffe2\uff80\uff93clay mixtures with different compositions. The experimental results indicated that the optimum initial moisture content decreased as the sand content increased. The optimum XG content, which also decreased with the increasing sand content, remained approximately 3.75% for all sand\uffe2\uff80\uff93kaolin mixtures and 5.75% for all sand\uffe2\uff80\uff93bentonite mixtures if calculated based on clay fraction. While untreated sand\uffe2\uff80\uff93kaolin mixtures and sand\uffe2\uff80\uff93bentonite mixtures had comparable UCS values, XG-treated sand\uffe2\uff80\uff93kaolin mixtures seemed to have better improved mechanical strength due to higher ionic (or hydrogen) bonds with XG and low-swelling properties compared with bentonite. The deformation modulus of XG-treated sand\uffe2\uff80\uff93clay mixtures were positively related with UCS. The variation in UCS and stiffness for each treatment condition increased as the sand content was elevated for both sand-kaolin and sand-bentonite mixtures. An increment in the proportion of the heterogeneous composite formed by irregular sand particles conglomerated with the XG\uffe2\uff80\uff93clay matrix in total soil might be responsible for this phenomenon.</p>", "keywords": ["Civil and Environmental Engineering", "TP", "initial moisture content", "engrXiv|Engineering|Civil and Environmental Engineering|Civil Engineering", "bepress|Engineering", "bentonite", "xanthan gum", "QK", "TN", "0211 other engineering and technologies", "sand-clay mixture", "02 engineering and technology", "uniaxial compressive strength tests", "bepress|Engineering|Civil and Environmental Engineering|Civil Engineering", "Civil Engineering", "6. Clean water", "Engineering", "engrXiv|Engineering", "TA", "bepress|Engineering|Civil and Environmental Engineering", "engrXiv|Engineering|Civil and Environmental Engineering", "QE", "kaolin", "biopolymer content"], "contacts": [{"organization": "Geng, Xueyu, Ma, Lei, Hao, Gang-Lai, Ni, Jing, Chen, Jia-Qi,", "roles": ["creator"]}]}, "links": [{"href": "http://wrap.warwick.ac.uk/150469/7/WRAP-Optimisation-analysis-sand-clay-mixtures-stabilised-xanthan-gum-biopolymers-2021.pdf"}, {"href": "http://www.mdpi.com/2071-1050/13/7/3732/pdf"}, {"href": "https://www.mdpi.com/2071-1050/13/7/3732/pdf"}, {"href": "https://doi.org/10.3390/su13073732"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Sustainability", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/su13073732", "name": "item", "description": "10.3390/su13073732", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/su13073732"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-03-26T00:00:00Z"}}, {"id": "181a31e0-8157-11dc-990b-0017f293bd28", "type": "Feature", "geometry": {"type": "Polygon", "coordinates": [[[-180.0, -90.0], [-180.0, 90.0], [180.0, 90.0], [180.0, -90.0], [-180.0, -90.0]]]}, "properties": {"themes": [{"concepts": [{"id": "geoscientificInformation"}], "scheme": "https://standards.iso.org/iso/19139/resources/gmxCodelists.xml#MD_TopicCategoryCode"}], "updated": "2019-11-22T10:23:04", "language": "eng", "title": "Thermal Climate", "description": "The raster dataset of thermal climates has a spatial resolution of 5 * 5 arc minutes and is in geographic projection. Information with regard to thermal climates was obtained from the \"Derived Soil Properties\" of the FAO-UNESCO Soil Map of the World which contains raster information on soil properties.", "formats": [{"name": "WWW:LINK-1.0-http--link"}, {"name": "WWW:DOWNLOAD-1.0-http--download"}], "keywords": ["subsoil", "cations", "soil", "kaolinites", "Digital Soil Map of the World", "Tag_soils", "World"], "contacts": [{"name": "Freddy Nachtergaele", "organization": "FAO-UN - AGLL (former FAO Land and Water Division)", "position": "Senior Officer Land Resources (Retired)", "roles": ["author"], "phones": [{"value": null}], "emails": [{"value": "land-and-water@fao.org"}], "addresses": [{"deliveryPoint": [null], "city": null, "administrativeArea": null, "postalCode": null, "country": null}], "links": [{"href": null}]}, {"organization": "FAO-UN - AGLL (former FAO Land and Water Division)", "roles": ["contributor"]}], "edition": "3.6"}, "links": [{"href": "http://www.fao.org/nr/land/pubs/digital-media-series/en/", "description": "FAO Land Resources - Digital Media Series (20)", "protocol": "WWW:LINK-1.0-http--link", "rel": null}, {"href": "https://storage.googleapis.com/fao-maps-catalog-data/uuid/181a31e0-8157-11dc-990b-0017f293bd28/resources/thermalclimate.zip", "description": "Cation Exchange Capacity (clay) - Subsoil - ESRI GRID dataset", "protocol": "WWW:DOWNLOAD-1.0-http--download", "rel": null}, {"href": "https://storage.googleapis.com/fao-maps-catalog-data/uuid/181a31e0-8157-11dc-990b-0017f293bd28/resources/thcli_ASCII.zip", "description": "Cation Exchange Capacity (clay) - Subsoil - ASCII GRID dataset", "protocol": "WWW:DOWNLOAD-1.0-http--download", "rel": null}, {"rel": "self", "type": "application/geo+json", "title": "181a31e0-8157-11dc-990b-0017f293bd28", "name": "item", "description": "181a31e0-8157-11dc-990b-0017f293bd28", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/181a31e0-8157-11dc-990b-0017f293bd28"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date-time": "2019-11-22T10:23:04Z"}}, {"id": "6d2f9dcc3206843e4a962414751c303c", "type": "Feature", "geometry": null, "properties": {"updated": "2022-11-25T00:00:00Z", "type": "Dataset", "language": "fr", "externalIds": [{"value": "https://geodata.wallonie.be/id/f8a238fd-d87b-456f-be48-d6f96f83b4fe"}], "title": "INSPIRE - Areas occupied by working quarries between 2010 and 2020 in Wallonia (BE)", "description": "This INSPIRE compliant data layer represents the influence of active careers in Wallonia in 2020.  The initial list comes from the 2010 Poty Inventory.  This layer includes for each site in operation (= active quarries) the land occupied by:  - the extraction pit: this is the area where the stone is extracted, which itself includes the working floor (bottom), bearings, face faces including the excavation of waste rock (also known as dead ground);  - operating dependencies: all the facilities present on the quarry site and which enable the stone to be transformed into a finished or semi-finished product (breaking, screening, washing, concrete plant, coating, handling, stone working, workshops, garages, product stocks, car parks, processing plant, brick-making, lime kilns, etc.);  - operating waste rock depots, settling ponds, and runways allowing the movement of machinery within the holding and direct connections to the railway or waterway, buffer or isolation zones on the periphery of the site.   It is very important to point out that this layer does not correspond to the land covered by the permits, nor to the land listed in the area of extraction dependencies or in the area of extraction in the sector plan in force. Similarly, it is important to stress that this layer does not represent only the bare soils of active quarries.    The information awarded is the Poty ID (links to other parts of the study), the name of the quarry, the materials used and the family of rocks.", "formats": [{"name": "GEOJSON"}], "keywords": ["High value dataset", "ame\u0301nagement-du-territoire", "-urbanisme", "-ba\u0302timents", "-e\u0301quipements", "-logement", "ardoise", "argile", "arkose", "be", "calcaire", "carrie\u0300re", "coticule", "craie", "dolomie", "environnement", "exploitation-de-carrie\u0300re", "exploitation-minie\u0300re", "e\u0301conomie", "-business", "-pme", "-de\u0301veloppement-e\u0301conomique", "-emploi", "gre\u0300s", "industrie", "industrie-minie\u0300re", "kaolin", "lieux-de-production-et-sites-industriels", "limon", "marbre", "marbre-noir", "marne", "nuisance", "phyllade", "pierre", "pierre-naturelle", "pierre-ornementale", "porphyre", "psammite", "quartzite", "quartzophyllade", "re\u0301gional", "sable", "schiste", "silex", "sol", "terre-a\u0300-brique", "tuffeau"], "contacts": [{"organization": "Helpdesk carto du SPW (SPW - Secr\u00e9tariat g\u00e9n\u00e9ral - SPW Digital - D\u00e9partement Donn\u00e9es transversales - Gestion et valorisation de la donn\u00e9e)", "roles": ["creator"]}, {"organization": "https://org.belgif.be/id/CbeEstablishmentUnit/2204322327", "roles": ["publisher"]}]}, "links": [{"href": "https://geodata.wallonie.be/dataset/706cbad4-25ea-443e-a3ee-002c58deb63d"}, {"href": "https://geoservices.wallonie.be/geoserver/inspire_pf/ogc/features/v1/openapi"}, {"href": "https://geoservices.wallonie.be/geoserver/inspire_pf/ows?service=WMS&version=1.3.0&request=GetCapabilities"}, {"href": "https://metawal.wallonie.be/geonetwork/srv/api/records/706cbad4-25ea-443e-a3ee-002c58deb63d"}, {"href": "http://data.europa.eu/88u/dataset/https-geodata-wallonie-be-id-706cbad4-25ea-443e-a3ee-002c58deb63d"}, {"href": "https-geodata-wallonie-be-id-706cbad4-25ea-443e-a3ee-002c58deb63d"}, {"href": "https://geodata.wallonie.be/id/706cbad4-25ea-443e-a3ee-002c58deb63d"}, {"rel": "self", "type": "application/geo+json", "title": "6d2f9dcc3206843e4a962414751c303c", "name": "item", "description": "6d2f9dcc3206843e4a962414751c303c", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/6d2f9dcc3206843e4a962414751c303c"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"null": "date"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=kaolin&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=kaolin&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=kaolin&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=kaolin&offset=5", "hreflang": "en-US"}], "numberMatched": 5, "numberReturned": 5, "distributedFeatures": [], "timeStamp": "2026-09-21T22:46:18.138629Z"}