Effect of K2SO4 concentration on extractability and isotope signature (δ13C and δ15N) of soil C and N fractions. (20th April 2015)

• Record Type: Journal Article
• Authors: Makarov, M. I.; Malysheva, T. I.; Menyailo, O. V.; Soudzilovskaia, N. A.; Van Logtestijn, R. S. P.; Cornelissen, J. H. C.
• Is Part Of: European journal of soil science. Volume 66:Number 3(2015)
• Page Start: 417
• Page End: 426
• Publication Date: 2015-04-20
• Subjects: Soil science -- Periodicals; 631.4
• DOI: 10.1111/ejss.12243
• Languages: English
• ISSNs: 1351-0754

Abstract

<abstract abstract-type="main" id="ejss12243-abs-0001"> <title>Summary</title> <p id="ejss12243-para-0001">Determination of the labile soil carbon (C) and nitrogen (N) fractions and measurement of their isotopic signatures (δ<sup>13</sup>C and δ<sup>15</sup>N) has been used widely for characterizing soil C and N transformations. However, methodological questions and comparison of results of different authors have not been fully solved. We studied concentrations and δ<sup>13</sup>C and δ<sup>15</sup>N of salt‐extractable organic carbon (SEOC), inorganic (N–NH<sub>4</sub><sup>+</sup> and N–NO<sub>3</sub><sup>−</sup>) and organic nitrogen (SEON) and salt‐extractable microbial C (SEMC) and N (SEMN) in 0.05 and 0.5 <sc>m</sc> K<sub>2</sub>SO<sub>4</sub> extracts from a range of soils in Russia. Despite differences in acidity, organic matter and N content and C and N availability in the studied soils, we found consistent patterns of effects of K<sub>2</sub>SO<sub>4</sub> concentration on C and N extractability. Organic C and N were extracted 1.6–5.5 times more effectively with 0.5 <sc>m</sc> K<sub>2</sub>SO<sub>4</sub> than with 0.05 <sc>m</sc> K<sub>2</sub>SO<sub>4</sub>. Extra SEOC extractability with greater K<sub>2</sub>SO<sub>4</sub> concentrations did not depend on soil properties within a wide range of pH and organic matter concentrations, but the effect was more pronounced in the most acidic and organic‐rich mountain Umbrisols. Extractable microbial C was not affected by K<sub>2</sub>SO<sub>4</sub> concentrations, while SEMN was greater when extracted with 0.5 <sc>m</sc> K<sub>2</sub>SO<sub>4</sub>. We demonstrate that the δ<sup>13</sup>C and δ<sup>15</sup>N values of extractable non‐microbial and microbial C and N are not affected by K<sub>2</sub>SO<sub>4</sub> concentrations, but use of a small concentration of extract (0.05 <sc>m</sc> K<sub>2</sub>SO<sub>4</sub>) gives more consistent isotopic results than a larger concentration (0.5 <sc>m</sc>).</p> </abstract>