Pedosphere 28(1): 103--113, 2018
ISSN 1002-0160/CN 32-1315/P
©2018 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Soil Respiration of Biologically-Crusted Soils in Response to Simulated Precipitation Pulses in the Tengger Desert, Northern China
LI Xiaojun, ZHAO Yang, YANG Haotian, ZHANG Peng, GAO Yongping
Shapotou Desert Research and Experiment Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000 (China)
Corresponding Author:LI Xiaojun
ABSTRACT
      Soil respiration (SR) is a major process of carbon loss from dryland soils, and it is closely linked to precipitation which often occurs as a discrete episodic event. However, knowledge on the dynamic patterns of SR of biologically-crusted soils in response to precipitation pulses remains limited. In this study, we investigated CO2 emissions from a moss-crusted soil (MCS) and a cyanobacterialichen-crusted soil (CLCS) after 2, 4, 8, 16, and 32 mm precipitation during the dry season in the Tengger Desert, northern China. Results showed that 2 h after precipitation, the SR rates of both MCS and CLCS increased up to 18-fold compared with those before rewetting, and then gradually declined to background levels; the decrease was faster at lower precipitation amount and slower at higher precipitation amount. The peak and average SR rates over the first 2 h in MCS increased with increasing precipitation amount, but did not vary in CLCS. Total CO2 emission during the experiment (72 h) ranged from 1.35 to 5.67 g C m-2 in MCS, and from 1.11 to 3.19 g C m-2 in CLCS. Peak and average SR rates, as well as total carbon loss, were greater in MCS than in CLCS. Soil respiration rates of both MCS and CLCS were logarithmically correlated with gravimetric soil water content. Comparisons of SR among different precipitation events, together with the analysis of long-term precipitation data, suggest that small-size precipitation events have the potential for large short-term carbon losses, and that biological soil crusts might significantly contribute to soil CO2 emission in the water-limited desert ecosystem.
Key Words:  biological soil crusts,C cycling,CO2 emission,desert ecosystem,precipitation amount,soil water content
Citation: Li X J, Zhao Y, Yang H T, Zhang P, Gao Y P. 2018. Soil respiration of biologically-crusted soils in response to simulated precipitation pulses in the Tengger Desert, northern China. Pedosphere. 28(1):103-113.
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