Land-use change under different climatic conditions: Consequences for organic matter and microbial communities in Siberian steppe soils

Bischoff, Norbert; Mikutta, Robert; Shibistova, Olga; Пузанов, А. В.; Reichert, Evgeny; Силантьева, Марина Михайловна; Grebennikova, Anna; Schaarschmidt, Frank; Heinicke, Steffen; Guggenberger, Georg

doi:10.1016/j.agee.2016.10.022

Cited by 35 publications

(31 citation statements)

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“…This contrasts with observations from the steppe soils (mostly Chernozems) of European Russia (Breulmann et al, 2014;Kalinina et al, 2011), Canada (Plante et al, 2010), and China (Steffens et al, 2010) in which particulate OC represented > 20 % of bulk OC. Nevertheless, our results are in line with Bischoff et al (2016), who reported that a maximum of 10 % OC was present as particulate OC in the Chernozems and Kastanozems of the Kulunda steppe. Thus, we support previous observations from this region and conclude that mineralbound OM is the dominant OM fraction in both salt-and non-salt-affected soils of the studied region.…”

Section: Partitioning and Composition Of Soil Om In Functionally Diffsupporting

confidence: 82%

“…Larger OC stocks in salt-affected soils than in Kastanozems are also in contrast to earlier work, which found a negative effect of salinity on soil OC stocks (reviewed by Wong et al, 2010). Possible reasons for the observed differences are climatic variations between the studies (strong aridity in the Spanish Solonchaks from Muñoz-Rojas et al, 2012) or alterations in soil texture (finer textured Kastanozems in the study from Bischoff et al, 2016), which may change the soil water balance and thus plant growth and soil OC inputs. However, it appears that the covarying moisture gradient along the salinity transect is a better explanation for the observed differences.…”

Section: Soil Oc Stocks Along the Salinity Gradientcontrasting

confidence: 54%

“…With average OC stocks of 70.9 ± 2.8 Mg ha −1 in 0-100 cm of depth for the Kastanozems, the values were clearly below those observed by Batjes (1996) and calculated from Bischoff et al (2016). On the other hand, average OC stocks of 94.2 ± 6.9 and 129.5 ± 25.6 Mg ha −1 in 0-100 cm of the non-sodic Solonchaks and Sodic Solonchaks, respectively, were clearly above the values reported by Batjes (1996) and Muñoz-Rojas et al (2012).…”

Section: Soil Oc Stocks Along the Salinity Gradientmentioning

confidence: 83%

“…Kastanozems, on the other hand, contained on average 96 Mg ha −1 (CV: 50 %) in the first meter, at which Haplic Kastanozems had soil OC stocks above that average of 138 Mg ha −1 (CV: 44 %; Batjes, 1996). Based on data from Bischoff et al (2016), we calculated soil OC stocks in Kastanozems of the dry steppe type in the Kulunda steppe down to 60 cm, which amounted to 110 ± 6 Mg ha −1 . All of the previously published data confirm that salt-affected soils like Solonchaks normally have smaller OC stocks than the non-salt-affected Kastanozems.…”

Section: Soil Oc Stocks Along the Salinity Gradientmentioning

confidence: 99%

“…The texture of the soils was determined according to the standard sieve-pipette method (DIN ISO 11277, 2002) and the content of oxalate-and dithionite-extractable Fe was analyzed as described in McKeague and Day (1966). Soil aggregate stability was measured based on a method modified from Hartge and Horn (1989) and explained in detail in Bischoff et al (2016). It was calculated as the difference between the mean weight diameter (MWD) of aggregates of a dry-and a wet-sieving method, expressed as MWD, with a high MWD corresponding to low aggregate stability and a low MWD relating to high aggregate stability.…”

Section: Sample Preparation and Basic Soil Analysesmentioning

confidence: 99%

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Organic matter dynamics along a salinity gradient in Siberian steppe soils

et al. 2018

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Abstract. Salt-affected soils will become more frequent in the next decades as arid and semiarid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these soils, though OM is crucial for soil fertility and represents an important carbon sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in the soils of the southwestern Siberian Kulunda steppe (Kastanozem, non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes (δ 13 C, 14 C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Aboveground biomass was measured as a proxy for plant growth and soil OC inputs. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks compared to non-salt-affected Kastanozems, (iii) sodicity reduces the proportion and stability of mineral-associated OM, and (iv) the fungi : bacteria ratio is negatively correlated with salinity. Against our first hypothesis, OC stocks increased along the salinity gradient with the most pronounced differences between topsoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only < 10 % in all three soil types, while mineral-associated OM contributed > 90 %. Isotopic data (δ 13 C, 14 C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient and that particulate OM was not more persistent under saline conditions. Our third hypothesis was also rejected, as Sodic Solonchaks contained more than twice as much mineral-bound OC than the Kastanozems, which we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. Contrary to the fourth hypothesis, the fungi : bacteria ratio in the topsoils remained fairly constant along the salinity gradient. A possible explanation for why our hypotheses were not affirmed is that soil moisture covaried with salinity along the transect, i.e., the Solonchaks were generally wetter than the Kastanozems. This might cause comparable water stress conditions for plants and microorganisms, either due to a low osmotic or a low matric potential and resulting in (i) similar plant growth and hence soil OC inputs along the transect, (ii) a comparable persistence of particulate OM, and (iii) unaffected fungi : bacteria ratios. We conclude that saltaffected soils contribute significantly to the OC storage in the semiarid soils of the Kulunda steppe, while most of the Published by Copernicus Publications on behalf of the European Geosciences Union. 14 N. Bischoff et al.: Organic matter dynamics along a salinity gradient OC is associated with minerals and is therefore effectively s...

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