【未来陆地C损失】Anna Armstrong. Future land-carbon loss. Nature Geoscience 6 330 (2013) doi:10.1038-ngeo1819
Human activities have altered around one-third to one-half of the world's land surface with significant consequences for climate particularly in the high latitudes. Climate model simulations suggest that future changes in land use could further alter regional climate over the coming century.
【凋落物分解过程中的质量损失和养分动力学】Yulian Tan Jin Chen Liming Yan Jianhui Huang Lixin Wang Shiping Chen. Mass loss and nutrient dynamics during litter decomposition under three mixing treatments in a typical steppe in Inner Mongolia.Plant and Soil
Abstract
Background and aims
Mixing effects during litter decomposition could occur between two or more different litter species because of the potential nutrient transfer. However evidence of mixing effects is variable and the underlying mechanisms remain unclear. Using a three-year decomposition experiment we aim to examine for the effects of litter mixing and position on decomposition rates and nitrogen (N) and phosphorus (P) dynamics.
Methods
We studied litter decomposition of Stipa krylovii (Sk) and Astragalus galactites (Ag) two dominant species with contrasting litter quality in a typical steppe of northern China in both single decomposition and three mixing treatments. The three mixing treatments included thorough mixing (Sk-Ag) Ag over Sk (Ag-Sk) and Sk over Ag (Sk-Ag).
Results
Both the Sk-Ag and the Sk-Ag mixture had negative mixing effects on the mass loss of the litter mixture while the Ag-Sk mixture had a neutral mixing effect. The percent mass loss was higher when the litter species was placed at the top (25.0 and 51.9 % of mass remaining for Ag and Sk respectively) than at the bottom (38.3 and 61.8 % of mass remaining for Ag and Sk respectively). The Sk-Ag mixture had negative effects on the release of N while all three mixing treatments had positive effects on the release of P.
Conclusions
Our results indicate that: (1) mixing treatments can induce different mixing effects; (2) environmental factors likely play an important role in controlling the mi