Response of soil respiration to experimental warming in a highland barley of the Tibet.

Zhi-Ming Zhong,Gang Fu,Zhen-Xi Shen

doi:10.1186/s40064-016-1761-0

Abstract

Highland barley is an important dominant crop in the Tibet and the croplands of the Tibet are experiencing obvious climatic warming. However, information about how soil respiration will respond to climatic warming in the highland barley system is still lacking. A field warming experiment using infrared heaters with two warming magnitudes was conducted in a highland barley system of the Tibet in May 2014. Five daily cycles of soil respiration was measured using a CO2 flux system (Li-8100, Li-COR Biosciences, Lincoln, NE, USA) during the period from early June to early September in 2014. The high and low experimental warming significantly increased soil temperature by 1.98 and 1.52 °C over the whole study period, respectively. The high experimental warming significantly decreased soil moisture. Soil respiration and its temperature sensitivity did not significantly change under both the high and low experimental warming. The response of soil respiration to experimental warming did not linearly correlate with warming magnitudes because a greater experimental warming resulted in a higher soil drying. Our findings suggested that clarifying the response of soil CO2 production and its temperature sensitivity to climatic warming need consider water availability in the highland barley system of the Tibet.

Highlights

The global surface temperature is predicted to increase by 1.0–3.7 °C by the end of this century and the Tibetan Plateau, “the Third Pole of the Earth”, is one of the most sensitive regions to climatic warming (Fu et al 2015; IPCC 2013)
There were significant positive responses of Rs to experimental warming in the alpine meadow of the Haibei station (Lin et al 2011) and the Songpan County (Shi et al 2012), an alpine steppe of the Northern Tibet (Lu et al 2013) and forest ecosystems (Xu et al 2010) on the Tibetan Plateau. These findings implied that the alpine ecosystems on the Tibetan Plateau did not always show a positive response of Rs to climatic warming. These results indicated that the effect of climatic warming on Rs varied with ecosystems and regions on the Tibetan Plateau
Experimental warming-induced soil drying masked the effect of increased soil temperature on soil respiration in the highland barely system

Summary

Introduction

The global surface temperature is predicted to increase by 1.0–3.7 °C by the end of this century and the Tibetan Plateau, “the Third Pole of the Earth”, is one of the most sensitive regions to climatic warming (Fu et al 2015; IPCC 2013). The croplands are experiencing obvious warming on the Tibetan Plateau (Shen et al 2014) and about 80 % of the population lives in the cropland areas of the Tibet (Yang et al 1996). These suggest that it remains unclear about how alpine agricultural ecosystems respond to future climatic warming on the Tibetan Plateau. No studies demonstrate the warming effects on highland barley ecosystem under controlled warming on the Tibetan Plateau.

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Conclusion