Status of Sulphur in Soils and Plants of Thirty Countries [antikvár]

Preface This report on the status of sulphur in soils and plants, undertaken by the Agricultural Research Centre of Finland in cooperation with FAO, augments earlier studies published as Soils Bulletins 17, 48, 63 and 65 by FAO on a wide range of plant nutrients (both macro- and micro-) for various countries around the world (Sillanpaa, 1972a; 1982; 1990; Sillanpaa and Jansson, 1992). Sulphur, though just as relevant as other macronutrients, was not dealt with in the earlier reports because there were difficulties in analysis. In recent years, with the relatively new techniques of plasma emission spectroscopy, it has been possible to assemble appropriate data. The unique set of plant and soil samples collected from thirty countries for one of the earlier projects was used for this study. As in the previous studies, the results of this work are strictly comparable because the samples were taken using standard techniques and all the analyses were undertaken in one laboratory using uniform methods. Plasma emission spectroscopy was not available at the Agricultural Research Centre, Jokioinen, in time for the 1982 report (Sillanpaa, 1982) but during studies for Sillanpaa's 1990 report, plasma emission spectroscopy became available and sulphur was determined for irrigation waters, and subsequently for the standard samples from the thirty countries. The purpose of the 1982 study at its initiation in 1973 was to produce fresh information on a woridwide basis on the problems of a number of micronutrients under different soil, climatic and cultural conditions . Since then the scope has widened to include other nutrients. In this study sulphur was extracted from soil using the AAAc-EDTA method (Lakanen and Ervio 1971). This is not necessarily the best extractant for this element but it is suitable for a range of elements and was used as a multi-extractant in the earlier studies. At the start of the sulphur work soil sample material was In short supply from some of the sites, but stored AAAc-EDTA extracts were available. Thus is was possible to assemble data for almost 3600 sites. Analyses based on samples taken in the 1970s are not necessarily ideal but, combined with data from other subsequent work in various countries, their global uniformity and wide range enables overall appraisal of sulphur status especially for countries that hitherto have had only sparse data. Background information on general soil properties drawn from the eariier reports is included in this report as also are data on Cd, Pb, Co and Se. Though extractable soil sulphur generally correlates well with plant sulphur, the reasons for the anomalous status of various plant/soil data points in the international field' have been checked by reference to the original Field Information Forms.