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.
Subjects: Biology >> Botany >> Applied botany submitted time 2019-02-25 Cooperative journals: 《广西植物》
Abstract：岩溶植被修复是国家重大战略需求，揭示封育年限对岩溶植被组成和土壤肥力修复的影响，可为岩溶植被修复和管理提供理论依据。以空间代替时间的方法，选择不同封育年限的草丛（封育 5 a）、灌丛（15 a）、灌乔林（25 a）、次顶极乔林（35 a）和顶极乔林（55 a）作为研究对象，调查分析不同封育年限岩溶植被组成和土壤肥力的特征及其修复机制。结果表明：研究样地（18 000 m2）共有维管植物 175 种，隶属 74 科 139 属，不同封育年限群落科属种组成明显不同，以封育 5 a 的最低（6 科 19 属 20 种），封育 35 a 的最高（48 科 74 属88 种）。随着封育期延长，乔木生活型比例显著增加，灌木为先增后减，草本急剧减少，藤本先增后减。随着进展演替，群落不同层次的优势种替代规律不同，草本层为阳性杂草→阳性禾草→中生性或阴生性蕨类植物的有序性替代；灌木层为灌木种类被乔木幼苗幼树所替代；而乔木层却表现为常绿种类占优势到常绿与落叶树种共优势的结构性替代。封育初期群落物种组成简单，多样性较低，土壤有机质、全氮、有效氮含量较低，进入中期（25 a），多样性升高，土壤养分含量也增高，进入后期（55 a），多样性降低，土壤养分含量也相应下降，但维持在较高水平，表现出较强的协同修复效应。冗余分析（RDA）表明，群落物种组成在封育初期受土壤容重、毛管孔隙度、全钾、速效钾、速效磷的显著影响，而在中后期则受土壤有机质、水分含量、非毛管孔隙度、全氮、有效氮以及碳氮磷化学计量比的显著影响。
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