Soil salinity and carbonate mineralogy

Non-Peer ReviewedThe growing concern over the apparent increased salinization of soils within the prairie region of Canada and the U.S.A. is reflected in the many papers and workshops dealing with this subject over the last few years. In Saskatchewan, provincial and federal research and extension agencies have observed and described various situations where salinization appears to be increasing, and have attempted to document these increases and implement remedial action. While causes of salinization, such as seepage or restricted drainage, may appear obvious in some cases, there are many situations where a complete understanding of the salinization processes are not known due to the lack of information for the specific sites. Ongoing studies dealing with the nature and genesis of secondary carbonates in soils suggest a possible tie-in between soil salinity and the nature of secondary calcites. Such a relationship may offer a means of evaluating the attendant conditions under which salinization occurs. This paper deals with the theoretical background and field evidence related to this relationship

The mineralogical composition of calcium and calcium-magnesium carbonate pedofeatures of calcareous soils in the European prairie ecodivision in Hungary

Abstract There is little data on the mineralogy of carbonate pedofeatures in the calcareous soils in Hungary which belong to the European prairie ecodivision. The aim of the present study is to enrich these data. The mineralogical composition of the carbonate pedofeatures from characteristic profiles of the calcareous soils in Hungary was studied by X-ray diffractometry, thermal analysis, SEM combined with microanalysis, and stable isotope determination. Regarding carbonate minerals only aragonite, calcite (+ magnesian calcite) and dolomite (+proto-dolomite) were identified in carbonate grains, skeletons and pedofeatures. The values relating, respectively, to stable isotope compositions (C13, O18) of carbonates in chernozems and in salt-affected soils were in the same range as those for recent soils (latter data reported earlier). There were no considerable differences between the values for the carbonate nodules and tubules from the same horizons, nor were there significant variations between the values of the same pedofeatures from different horizons (BC-C) of the same profile. Thus it can be assumed that there were no considerable changes in conditions of formation. Tendencies were recognized in the changes of (i) carbonate mineral associations, (ii) the MgCO3 content of calcites, (iii) the corrected decomposition temperatures, and (iv) the activation energies of carbonate thermal decompositions among the various substance-regimes of soils. Differences were found in substance-regimes types of soils rather than in soil types