Abstract
Widely distributed shrubs in drylands can locally alter soil physicochemical properties, which distinguish soil under plant canopy from soil outside the canopy. In the present study, we used a dominant shrub species Artemisia gmelinii in a semiarid land, SW China, to investigate the consequences of “shrub resource islands” for soil microbial communities and enzymatic activities. Such investigation was made at four sites that differed in rates of rainfall to examine how the consequences were altered by variation in the local climate. The results showed that A. gmelinii enhanced fungal abundance but did not influence bacterial abundance, resulting in higher total microbial abundance and fungal-to-bacterial ratio in under-canopy soil compared to outside-canopy soil. Microbial community composition also differed between the two soils, but this difference only occurred at sites of low rainfall. Redundancy analysis revealed that such composition was attributed to variation in soil water content, bulk density, and total phosphorus as a result of shrub canopy and varying rates of rainfall. Activities of hydrolytic enzymes (β-1,4-glucosidase, β-1,4-N-acetylglucosaminidase, alkaline phosphatase, and leucine aminopeptidase) were higher in under-canopy soil than in outside-canopy soil, among which C-acquisition enzyme, β-1,4-glucosidase, and P-acquisition enzyme, alkaline phosphatase, were also higher in the soil of high rainfall. The overall pattern of enzyme activities did not show differences between under- and outside-canopy soils, but it separated the sites of high rate from that of low rates of rainfall. This pattern was primarily driven by variation in soil physicochemical properties rather than variation in soil microbial community, suggesting that the distribution pattern of enzyme activities may be more sensitive to variation in rainfall than to shrub canopy. In conclusion, our study shows that shrub species A. gmelinii can shift the soil microbial community to be fungal-dominant and increase hydrolytic enzyme activities, and such effect may depend on local climatic variation, for example, rainfall changes in the semiarid land. The findings of this study highlight the important roles of shrub vegetation in soil biological functions and the sensitivity of such roles to climatic variation in semiarid ecosystems.
Highlights
Soil microbial community is a key component of underground biota and recognized vital roles in a wide range of soil processes, such as litter decomposition and nutrient cycling (Aislabie et al, 2013)
Soil organic carbon (SOC) was significantly higher in undercanopy soil of A. gmelinii than in outside-canopy soil and higher in soil collected from sites of high rainfall than in soil collected from sites of low rainfall
The biomarker for arbuscular mycorrhizal fungi (AMF) was higher in under-canopy soil, but only when the soils were collected from sites of low rainfall (Table 2; Figure 1G)
Summary
Soil microbial community is a key component of underground biota and recognized vital roles in a wide range of soil processes, such as litter decomposition and nutrient cycling (Aislabie et al, 2013). Soil microbial communities can secrete extracellular enzymes that take part in numerous soil processes (Brzostek et al, 2013) Among these enzymes, hydrolases are involved in C (e.g., β-glucosidases), N (e.g., β-1,4-N-acetylglucosaminidase and leucine aminopeptidase), and P (e.g., alkaline phosphatases) cycling and widely investigated in previous studies (Martinez and Tabatabai 1997; Roberts et al, 2007; Zhao et al, 2016; Li et al, 2019; Thapa et al, 2021). Hydrolases are involved in C (e.g., β-glucosidases), N (e.g., β-1,4-N-acetylglucosaminidase and leucine aminopeptidase), and P (e.g., alkaline phosphatases) cycling and widely investigated in previous studies (Martinez and Tabatabai 1997; Roberts et al, 2007; Zhao et al, 2016; Li et al, 2019; Thapa et al, 2021) The activities of these enzymes can quickly respond to changes in microbial communities and environmental conditions, and are, considered as sensitive indicators of microbial dynamics and environmental changes (Bowles et al, 2014). Environmental variations that affect a microbial community structure or hydrolytic enzyme activities in a soil may substantially alter the consequences of microbial-based soil processes (Ushio et al, 2008; Dick et al, 2015)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
