Soil aggregation and aggregate-associated organic carbon under typical natural halophyte communities in arid saline areas of Northwest China

Information on the effects of halophyte communities on soil organic carbon (SOC) is useful for sequestrating C in arid regions. In this study, we identified four typical natural halophyte communities in the Manasi River Basin in Xinjiang Province, Northeast China, namely, Karelinia caspia (Pall.) Less., Bassia dasyphylla (Fisch. et C. A. Mey.) Kuntze, Haloxylon ammodendron (C. A. Mey.) Bunge, and Tamarix ramosissima Lour. We compared soil aggregation and aggregated-associated SOC under these communities. The aggregate fraction of 0.053–0.25 mm accounted for 47%–75% of the total soil mass, significantly more than the > 0.25 and 0.25 mm aggregates (13.3%–43.8%) and T. ramosissima community having more 0.25 mm fraction, followed by the T. ramosissima (4.9 g kg−1) > K. caspia (4.2 g kg−1) > B. dasyphylla (3.4 g kg−1). The H. ammodendron community had the highest total SOC and aggregate-associated SOC, which was primarily because aggregate-associated SOC content at the 0–10 and 10–20 cm depths under this community were higher than those under other plant communities. The H. ammodendron community could be beneficial for increasing SOC in saline soils in the arid region.