The soil drying along the increase of warming masks the relation between temperature and soil respiration in an alpine meadow of Northern Tibet

A warming experiment with two magnitudes was performed in an alpine meadow of Northern Tibet since late June, 2013. Open top chambers (OTCs) with two top diameters (0.60 m and 1.00 m) were used to increase soil temperature. Soil respiration (R-S) was measured during the growing season in 2013-2014. The OTCs with top diameters of 1.00 m and 0.60 m increased soil temperature by 1.30 and 3.10 degrees C, respectively, during the whole study period, but decreased soil moisture by 0.02 and 0.05 m(3) m(-3), respectively. However, the two patters of OTCs did not affect R-S. These results implied that a higher warming did not result in a higher R-S but a greater soil drying. Therefore, a higher warming may not cause a higher soil respiration, which was most likely due to the fact that a higher warming may result in a greater soil drying