Harmonized World Soil Database Research Articles

A soil particle-size distribution dataset for regional land and climate modelling in China

We developed a multi-layer soil particle-size distribution dataset (sand, silt and clay content), based on USDA (United States Department of Agriculture) standard for regional land and climate modelling in China. The 1:1,000,000 scale soil map of China and 8595 soil profiles from the Second National Soil Survey served as the starting point for this work. We reclassified the inconsistent soil profiles into the proper soil type of the map as much as possible because the soil classification names of the map units and profiles were not quite the same. The sand, silt and clay maps were derived using the polygon linkage method, which linked soil profiles and map polygons considering the distance between them, the sample sizes of the profiles, and soil classification information. For comparison, a soil type linkage was also generated by linking the map units and soil profiles with the same soil type. The quality of the derived soil fractions was reliable. Overall, the map polygon linkage offered better results than the soil type linkage or the Harmonized World Soil Database. The dataset, with a 1-km resolution, can be applied to land and climate modelling at a regional scale.

Global Soil Organic Carbon Estimates and the Harmonized World Soil Database

Global estimates of soil organic carbon stocks have been produced in the past to support the calculation of potential emissions of CO2 from the soil under scenarios of change land use/cover and climatic conditions (IPCC, 2006), but very few global estimates are presented as spatial data. For global spatial layers on soil parameters, the most recent and complete dataset is available as the Harmonized World Soil Database (HWSD). The HWSD represents a step forward towards a spatially more detailed and thematically more refined set of global soil data. During the evaluation of the data for generating estimates of global SOC stocks Version 1.1 of the HWSD revealed also some rough edges. Consequential are the values of bulk density attributed to soils high in organic carbon. In the evaluation the database was completed and suitable substitutions for bulk density for soil high in organic carbon were investigated. For the amended data the global SOC stock to 100cm soil depth is estimated at 1,417 Pg C, although this estimate very much dependent on the ancillary data used. The amended HWSD was compared to data from 4 other global data sets on SOC stocks. The comparative evaluation has demonstrated that bulk density is the most important factor for estimating SOC stocks and mainly responsible for the differences between estimates. Most affected from the variability in bulk density are SOC stocks in areas with soils which are high in organic carbon. How to obtain EU publications Our priced publications are available from EU Bookshop (http://bookshop.europa.eu), where you can place an order with the sales agent of your choice. The Publications Office has a worldwide network of sales agents. You can obtain their contact details by sending a fax to (352) 29 29-42758. The mission of the JRC is to provide customer-driven scientific and technical support for the conception, development, implementation and monitoring of EU policies. As a service of the European Commission, the JRC functions as a reference centre of science and technology for the Union. Close to the policy-making process, it serves the common interest of the Member States, while being independent of special interests, whether private or national. LB -N A -2525-EN -N

Identifying the global potential for baobab tree cultivation using ecological niche modelling

The benefits provided by underutilised fruit tree species such as baobab (Adansonia digitata L.) in combating increasing malnutrition and poverty become more apparent as awareness grows regarding concerns of climate change and food security. Due to its multiple uses, its high nutritional and medicinal value, drought tolerance and relatively easy cultivation, baobab has been identified as one of the most important edible forest trees to be conserved, domesticated and valued in Africa. In order to contribute towards the cultivation of the species, suitability of sites in Africa and worldwide was evaluated for potential cultivation using species’ locality data and spatial environmental data in MAXENT modelling framework. A total of 450 geo-referenced records of the baobab tree were assembled from herbarium records, commercial firm’s databases and fieldwork for modelling site suitability for global cultivation of the baobab tree. Climatic and topographic data were acquired from the Worldclim data while soil data was obtained from the Harmonized World Soil Database. MAXENT was found to be a successful modelling method for studying cultivation potential. The main variables that contributed towards predicting baobab’s global cultivation potential were annual precipitation and temperature seasonality. Results suggest that baobab tree could be widely cultivated in most countries in southern Africa and in the Sudano-Sahelian zone of West Africa from Senegal to Sudan. Angola and Somalia were found to be highly suitable for cultivating baobab in Africa. Model suggests, India, where the baobab tree already exists and is used, to be the most suitable country for baobab cultivation outside Africa. North-west Australia, Madagascar, north-east Brazil and Mexico resulted to be other suitable places for cultivating the tree species. Although it is recommended model results be validated with in situ seedling experiments, there seems to be a great potential for the cultivation of this species globally.