A diverse collection of globally distributed soil samples was analyzed for its glycerol dialkyl glycerol tetraether (GDGT) membrane lipid content. Branched GDGTs, derived from anaerobic soil bacteria, were the most dominant and were found in all soils. Isoprenoid GDGTs, membrane lipids of Archaea, were also present, although in considerably lower concentration. Crenarchaeol, a specific isoprenoid membrane lipid of the non-thermophilic Crenarchaeota, was also regularly detected and its abundance might be related to soil pH. The detection of crenarchaeol in nearly all of the samples is the first report of this type of GDGT membrane lipid in soils and is in agreement with molecular ecological studies, confirming the widespread occurrence of non-thermophilic Crenarchaeota in the terrestrial realm. The fluvial transport of crenarchaeol and other isoprenoid GDGTs to marine and lacustrine environments could possibly bias the BIT index, a ratio between branched GDGTs and crenarchaeol used to determine relative terrestrial organic matter (TOM) input. However, as crenarchaeol in soils is only present in low concentration compared to branched GDGTs, no large effect is expected for the BIT index. The fluvial input of terrestrially derived isoprenoid GDGTs could also bias the TEX 86 , a proxy used to determine palaeo surface temperatures in marine and lacustrine settings and based on the ratio of cyclopentane-containing isoprenoid GDGTs in marine and lacustrine Crenarchaeota. Indeed, it is shown that a substantial bias in TEX 86 -reconstructed sea and lake surface temperatures can occur if TOM input is high, e.g. near large river outflows.

In the context of major global environmental challenges such as food security, climate change, fresh water scarcity and biodiversity loss, the protection and the sustainable management of soil resources in Africa are of paramount importance. To raise the awareness of the general public, stakeholders, policy makers and the science community to the importance of soil in Africa, the Joint Research Centre of the European Commission has produced the Soil Atlas of Africa. To that end, a new harmonised soil map at the continental scale has been produced. The steps of the construction of the new area-class map are presented, the basic information being derived from the Harmonized World Soil Database (HWSD). We show how the original data were updated and modified according to the World Reference Base for Soil Resources classification system. The corrections concerned boundary issues, areas with no information, soil patterns, river and drainage networks, and dynamic features such as sand dunes, water bodies and coastlines. In comparison to the initial map derived from HWSD, the new map represents a correction of 13% of the soil data for the continent. The map is available for downloading.

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Prediction of Soil Fertility Properties from a Globally Distributed Soil Mid-Infrared Spectral Library Nutrient Management & Soil & Plant Analysis S oil chemical and physical information is needed to give advice on land management. Th is is especially true in developing countries, where soil diagnostic surveillance systems have been proposed to overcome data shortages (Shepherd and Walsh, 2007). Mid-infrared (MIR) diff use refl ectance spectroscopy is a reliable and fast soil analytical tool (Janik et al., 1998) that could form a basis for diagnostic surveillance systems. Soil properties are predicted either by direct absorption of the light associated with functional groups (properties such as organic C, total N, or clay composition; Van der Marel and Beutelspacher, 1976) or by correlation to such properties and the mineral composition of the soil (properties such as cation exchange capacity [CEC] and soil texture). New samples can be predicted only if they fall within the property range of the calibration set (Naes et al., 2002). In many situations, a rapid and approximate estimate of soil chemical and physical properties is adequate, and resources for an elaborate analysis may not be available. A global calibration may meet this purpose. Some studies have tested soil infrared spectroscopy on diverse data sets at the regional scale. Reeves and Smith (2009), working with a North American library of 720 samples, came to the conclusion that neither MIR nor near-infrared (NIR) spectra yielded suitable calibrations even for organic C. Th ey attributed the poor performance to the extreme sample diversity in parent material, land

No abstract

No abstract

No abstract

No abstract

No abstract