Effect of grazing on carbon stocks and assimilate partitioning in a Tibetan montane pasture revealed by 13CO2 pulse labeling

By S. Hafner, Sebastian Unteregelsbacher, E. Seeber, Becker Lena, Xingliang Xu, Xiaogang Li, G. Guggenberger, G. Miehe, Y. Kuzyakov. 2012

253 citations recorded by the source corpus.

Since the late 1950s, governmental rangeland policies have changed the grazing management on the Tibetan Plateau (TP). Increasing grazing pressure and, since the 1980s, the privatization and fencing of pastures near villages has led to land degradation, whereas remote pastures have recovered from stronger overgrazing. To clarify the effect of moderate grazing on the carbon (C) cycle of the TP, we investigated differences in below‐ground C stocks and C allocation using in situ 13CO2 pulse labeling of (i) a montane Kobresia winter pasture of yaks, with moderate grazing regime and (ii) a 7‐year‐old grazing exclosure plot, both in 3440 m asl. Twenty‐seven days after the labeling, 13C incorporated into shoots did not differ between the grazed (43% of recovered 13C) and ungrazed (38%) plots. In the grazed plots, however, less C was lost by shoot respiration (17% vs. 42%), and more was translocated below‐ground (40% vs. 20%). Within the below‐ground pools, <2% of 13C was incorporated into living root tissue of both land use types. In the grazed plots about twice the amount of 13C remained in soil (18%) and was mineralized to CO2 (20%) as compared to the ungrazed plots (soil 10%; CO2 9%). Despite the higher contribution of root‐derived C to CO2 efflux, total CO2 efflux did not differ between the two land use types. C stocks in the soil layers 0–5 and 5–15 cm under grazed grassland were significantly larger than in the ungrazed grassland. However, C stocks below 15 cm were not affected after 7 years without grazing. We conclude that the larger below‐ground C allocation of plants, the larger amount of recently assimilated C remaining in the soil, and less soil organic matter‐derived CO2 efflux create a positive effect of moderate grazing on soil C input and C sequestration.

Subfields: Management, Monitoring, Policy and Law, Nature and Landscape Conservation, Soil Science

View Paper: https://www.semanticscholar.org/paper/c2cbec5e18ac75ecc55baccdf3e352b25507a995

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Management, Monitoring, Policy and Law

1. Johannes Kamp
2. Jürgen Dengler
3. K. Wesche

In Nature and Landscape Conservation

1. P. Török
2. Guirui Yu
3. Wenhua Xiang
4. Jürgen Dengler
5. J. Pausch
6. K. Wesche
7. Y. Kuzyakov
8. S. Kidwell

In Soil Science

1. J. Pausch
2. Y. Kuzyakov
3. Guirui Yu
4. K. Wesche
5. E. Blagodatskaya
6. W. Cheng
7. A. Gunina
8. C. Nguyen

Citations in the corpus

• The Palaearctic steppe biome: a new synthesis (2016, background): “Measurements, however, reveal complex patterns in response to changing climate (Yang et al. 2013) and land use, and both positive and negative effects of grazing have been reported (e.g. Wen et al. 2013 vs. Hafner et al. 2011).”
• Carbon input by roots into the soil: Quantification of rhizodeposition from root to ecosystem scale (2018, background): “Black triangles are data from studies conducted in montane ecosystems on the Tibetan Plateau (Gao et al., 2015; Hafner et al., 2012; Wu et al., 2010; Zhao et al., 2015) allocation or rhizodeposition in individual studies.”
• The impacts of climate change and human activities on biogeochemical cycles on the Qinghai‐Tibetan Plateau (2013, background): “One exception is moderate grazing, which may enhance carbon sequestration and increase the soil carbon stock (Hafner et al., 2012).”