Arid Zone Research ›› 2021, Vol. 38 ›› Issue (4): 961-972.doi: 10.13866/j.azr.2021.04.07

• Soil Resources • Previous Articles     Next Articles

Seasonal variation characteristics of different types of biological soil crust-soil system respiration in Mu Us Sandy Land

WANG Rongnv()   

  1. Northwest Surveying, Planning and Design Institute of National Forestry and Grassland Administration, Xi’an 710048, Shaanxi, China
  • Received:2020-12-05 Revised:2021-03-16 Online:2021-07-15 Published:2021-08-03

Abstract:

Biological soil crust is an important type of surface cover in arid and semi-arid areas, and it is an important component of the carbon cycle in desert ecosystems. However, research on seasonal changes in biological soil crust-soil system respiration is still very scarce, and it is difficult to accurately assess the carbon cycle processes of desert ecosystems over time. We examined the well-developed moss crust and algae crust in the southwest of Mu Us Sandy land in 2018, and we used moving sand as a control. The soil carbon flux measurement system was used to observe the daily dynamics of respiration of the biological soil crust-soil system in different seasons. The relationship between biological soil crust-soil system respiration and environmental factors was explored, and the effects of seasonal changes on biological soil crust-soil CO2 release and temperature sensitivity were analyzed. The results showed that there was a single peak in the biological soil crust-soil system respiration rate in different seasons, but the timing of the peak varied. The peak time of different types of biological soil crust-soil system respiration rates in spring and summer was 13:00, but in winter and autumn, the algae crust-soil system and moving sand respiration rate appeared around 15:00, lagging behind spring and summer by 2 h. In the same season, different types of biological soil crust-soil systems released different amounts of CO2: moss crust>algae crust>moving sand (P<0.05). With the change of season, the amount of CO2 released by the biological soil crust-soil systems first increased and then decreased, and the pattern mainly manifested as: summer>spring>autumn>winter (P<0.05). By analyzing the principal components of the biological soil crust-soil system respiration rate and environmental factors, we found that compared with the 5 cm temperature, the 2 cm soil temperature was the primary influencing factor of biological soil crust-soil system respiration in different seasons. The relationship between the biological soil crust-soil system respiration rate and the 2 cm soil temperature in different seasons showed a good fit with the exponential model. Based on this function, the temperature sensitivity of respiration was calculated. It was found that the temperature sensitivity varied from 1.33 to 3.85. With the change in seasons, the temperature sensitivity first decreased and then increased: winter>autumn>spring>summer. Therefore, the higher the temperature, the lower the temperature sensitivity of the biological soil crust-soil system respiration.

Key words: biological soil crusts, different season, respiration, Mu Us Sandy Land, temperature sensitivity