Abstract
BackgroundWe investigated the spatio-temporal dynamics of soil carbon dioxide (CO2)- and soil methane (CH4)-flux during biological soil crust (BSCs) deposition in a sand-binding area in the eastern Chinese Hobq Desert. The trends in soil organic carbon (C) content and density were analyzed during this process. The sampling sites comprised a mobile dune (control) and those with algal, lichen, and moss crust-fixed sands. The desert soil CO2- and CH4-flux, temperature, and water content were measured from May to October in 2017 and 2018. Simultaneously, organic C content and density were measured and analyzed by stratification.ResultsThe spatio-temporal variation in desert soil CO2-flux was apparent. The average CO2- fluxes in the control, algal, lichen, and moss sites were 1.67, 2.61, 5.83, and 6.84 mmol m−2 h−1, respectively, during the growing season, and the average CH4-fluxes in the four sites were − 1.13, − 1.67, − 3.66, and − 3.77 µmol m−2 h−1, respectively. Soil temperature was significantly positively correlated with CO2-flux but could not influence CH4 absorption, and C flux had minimal correlation with soil water content. The soil total organic C density at all sites was significantly different and decreased as follows: moss > lichen > algal > control; moreover, it decreased with soil depth at all sites. The accumulation of desert soil organic C could enhance soil C emissions.ConclusionIn a semi-arid desert, artificial planting could promote sand fixation and BSCs succession; therefore, increasing the C storage capacity of desert soils and decreasing soil C emissions could alter the C cycle pattern in desert ecosystems. Soil temperature is the major factor controlling desert soil CO2 flux and vegetation restoration, and BSCs development could alter the response patterns of C emissions to moisture conditions in desert soils. The results provide a scientific basis for studying the C cycle in desert ecosystems.
Highlights
We investigated the spatio-temporal dynamics of soil carbon dioxide (CO2)- and soil methane (CH4)-flux during biological soil crust (BSCs) deposition in a sand-binding area in the eastern Chinese Hobq Desert
The results provide a scientific basis for studying the C cycle in desert ecosystems
We examined the soil of an artificial sand-fixing area in the eastern Hobq Desert, using BSCs development as the basis for the division of sample sites, which were as follows: mobile dunes without crusts, algal crusted sandy land in the early developmental stage, lichen crusted sandy land in the middle stage, and moss crusted sandy land in the mature stage, with the aim of clarifying: (1) the spatiotemporal dynamics of soil C O2 and CH4 flux and its environmental controlling factors, (2) the dynamic variations in soil organic C (SOC) content and density, and (3) the synergistic relationship between C flux and C stock in desert soils during vegetation restoration and BSCs succession
Summary
We investigated the spatio-temporal dynamics of soil carbon dioxide (CO2)- and soil methane (CH4)-flux during biological soil crust (BSCs) deposition in a sand-binding area in the eastern Chinese Hobq Desert. Ecosystem carbon (C) stocks result from long-term C accumulation and comprise plant, litter, and soil C stocks. Their amounts can vary depending on ecosystem type, regional environmental conditions, and anthropogenic interventions, which are the theoretical basis for the. Small changes in soil C flux and organic C content, which are the important components of the pathway between the input and output of soil C pools, directly alter the C stocks in the pedosphere and atmosphere, thereby affecting ecosystem C cycling processes and global C balance [4]. The study of soil C fluxes and stocks in terrestrial ecosystems, especially the exploration of changes in soil C pools under different land-use patterns in the context of global climate change, can provide scientific basis for ecological management, such as plantation forest construction, natural forest protection, returning farmland to forests and grasslands, and desertification control, thereby clarifying its value and ensuring its rationality
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