Stoichiometric regulations of soil respiration and its temperature sensitivity under erosion and deposition conditions

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 2021-10, Vol.319, p.107507, Article 107507
• Main Authors: Tong, L.S., Xiao, H.B., Xu, K., Zhan, Y.M., Shi, Z.H.
• Format: Article
• Language: English
• Subjects: Soil deposition; Soil erosion; Soil respiration; Stoichiometry; Temperature sensitivity
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2021.107507

Soil erosion not only affects the redistribution of soil materials but also changes soil respiration (Rs) and its temperature sensitivity (Q10), which plays a significant role in the carbon cycle of terrestrial ecosystem. To explore the stoichiometric regulations of Rs and Q10 under erosion and deposition conditions, typical eroded (croplands) and deposited sites (check dams) were selected in the Luoyugou watershed of the Chinese Loess Plateau. In situ Rs, soil temperature and moisture were monitored. The results showed that soil deposition decreased soil organic carbon, total nitrogen, heavy fraction organic carbon and dissolved organic nitrogen by 20.0%, 26.7%, 20.1% and 49.1%, respectively. However, the higher ratios of carbon:nitrogen and labile carbon:organic carbon were observed in the deposited sites due to the accelerated loss of dissolved nitrogen and the selective transport of light fraction organic matter. The Rs displayed a decreasing trend from July to December, and soil temperature explained 69.5–93.6% of the temporal variation in Rs. The mean Rs was 2.18 and 2.89 μmol m−2 s−1 in the eroded and deposited sites, respectively, and the average Q10 was 2.49 and 3.38. Multiple stepwise regression analysis showed that soil organic carbon:total nitrogen and light fraction organic carbon totally explained 48.9% of the Rs variation, and the main control factors for Q10 were dissolved organic carbon: total organic carbon (34.6%), soil temperature (17.0%) and dissolved organic carbon (10.0%). Our results suggested that the ratios of carbon:nitrogen and labile carbon:organic carbon play an important role in regulating Rs and Q10, and the increase in carbon:nitrogen ratios induced by sediment deposition contributes to increasing Rs and Q10. We believe that the effects of erosion and deposition on Rs and Q10 revealed in the study will contribute to a better understanding of the terrestrial ecosystem carbon cycle. •Sediment deposition decreased soil nutrients but increased carbon:nitrogen ratios.•Higher Rs and Q10 were observed in depositional sites comparing to erosional sites.•Ratios of carbon:nitrogen and labile carbon:organic carbon affect most on Rs and Q10.•Deposition-induced increases in carbon:nitrogen ratios contribute to enhancing Rs.