Publication Type: | Journal Article |
Year of Publication: | 2010 |
Authors: | Walthert, L, Graf, U, Kammer, A, Luster, J, Pezzotta, D, Zimmermann, S, Hagedorn, F |
Journal: | Journal of Plant Nutrition and Soil Science |
Volume: | 173 |
Issue: | 2 |
Date Published: | 2010 |
ISBN Number: | 1522-2624 |
Keywords: | acid treatment, carbonate removal, dolomite, dry combustion, forest soils, soil organic matter |
Abstract: | In carbonate-containing soils a reliable determination of organic C requires a method that effectively separates organic and inorganic C without altering the organic matter. This study was conducted to determine whether HCl vapor completely removes carbonates even in dolomite-rich soils and to what extent a widely used acid-fumigation method has to be modified for humus-rich soils. Furthermore, it was tested whether HCl fumigation alters organic-C content. Since C and N parameters are often analyzed simultaneously we also tested the influence of acid-vapor treatment on N content and on δ13C of soil organic matter. We applied fumigation with 37% HCl for 8 and 32 h using 9 carbonate-containing soil samples. Inorganic C ranged from 7 to 124 and organic C from 9 to 267 g kg–1. The maximum contents of dolomite and calcite were 940 and 640 g kg–1, respectively. A time of 8 h was enough to completely remove all carbonates. Neither the content nor the δ13C of organic C were significantly affected by fumigation. In contrast, N contents were altered by acid treatment. Based on these results and on our experience in analyzing more than 1000 soil samples, a recommended procedure for acid fumigation of carbonate-containing soils with a wide range of organic- and inorganic-C contents was derived. Samples pretreated in this way can be analyzed reliably for their organic-C content and δ13C. Furthermore, N and inorganic-C contents can be determined with a quality sufficient for many purposes. |
URL: | http://dx.doi.org/10.1002/jpln.200900158 |
Short Title: | Journal of Plant Nutrition and Soil Science |