Subjects: Biology >> Botany >> Applied botany submitted time 2021-06-02 Cooperative journals: 《广西植物》
Abstract： In order to reveal the effects of different vegetation restoration modes on soil microbial communities in karst areas, this study took pure Dalbergia odorifera plantation (PDOP), pure Acrocarpus fraxinifolius plantation (PAFP) and their mixed plantation (MADP) as research subjects. The soil microbial biomass and microbial community structure of different plantations were analyzed by chloroform fumigation extraction method and phospholipids fatty acid (PLFA) method. The results were as follows: The soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) contents of PDOP were significantly higher than those of PAFP and MADP, and that of PAFP was significantly higher than that of the MADP. The contents of soil fungi, arbuscular mycorrhizal fungi (AMF) and total PLFA were not significantly different among the three plantations, but the contents of soil bacteria, actinomycetes, AMF and total PLFA in PDOP were higher than those in PAFP and MADP, and those in the PAFP were higher than those in MADP. The PLFA contents of bacteria, gram-positive bacteria, gram-negative bacteria and actinomycetes in PDOP were significantly higher than those in MADP. The ratio of fungi to bacteria in MADP was significantly higher than that in PDOP, but there were no significant differences between MADP and PAFP. Redundancy analysis showed that soil cation exchange capacity, pH, and C∶N were the most important factors affecting the functional group composition of soil microbial community. From the perspective of soil microbial biomass and microbial community structure of the three plantations, MADP in karst area did not show the advantage of mixed forest in acid soil region to improve soil microbial community structure. However, the ratio of fungi to bacteria in the mixed plantation is the highest, which is more conducive to improving the stability of soil ecosystem.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： The impact of Eucalyptus plantations on the ecological environment has been a hot topic of controversy worldwide. The ecological and environmental effects of a mixture of Eucalyptus and precious native tree species have attracted much attention. In order to explore the effects of management measures in mixed plantations on soil nutrients and understory plant functional groups, we assessed the understory plant communities and environmental factors using pure Eucalyptus plantations (PE), mixed Eucalyptus and Castanopsis hystrix plantations (MEC), and pure C. hystrix plantations (PCH). We found significant differences in the physicochemical properties of soil in the different stands. The soil pH, available nitrogen (AN) content, and available phosphorus (AP) content were significantly higher in MEC than in PE and PCH. However, we noted no significant advantages in terms of the soil moisture content (SMC), soil organic carbon (SOC) content, total nitrogen (TN) content, C:N ratio, and C:P ratio in MEC, with a trend of PE < MEC < PCH. On the other hand, the soil bulk density (SBD) and total phosphorus (TP) content showed a trend of PE > MEC > PCH. MEC significantly increased the species richness of the understory woody functional group (WFG), while PCH significantly increased the species richness of the ferns functional group (FeFG). The importance value of WFG and the Gramineae functional group (GFG) was significantly higher in MCH than in PCH, while the importance value of FeFG was significantly higher in PCH than in MCH. Principal coordinate analysis revealed no significant difference in the composition of understory plant functional groups between MEC and PE but revealed a significant difference between MEC and PCH. Moreover, redundancy analysis revealed that AN and AP were the main factors influencing the dominance of WFG. SMC, TN content, and SOC content were the main factors influencing the dominance of FeFG, while SBD was the main factor influencing the dominance of GFG. Thus, the mixture of Eucalyptus and C. hystrix could improve the availability of soil nutrients and the diversity of understory plant communities to some extent in subtropical China.
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