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。
Subjects: Biology >> Botany submitted time 2018-03-27 Cooperative journals: 《广西植物》
Abstract：林下植被是生态系统的重要组成成分，在维持森林垂直结构中发挥着不可或缺的作用。为了研究不同更新方式下桉树人工林林下植物功能群的变化规律及其主要影响因素，综合运用野外调查和室内分析的方法，评估桉树人工林林下植物功能群的组成、分布及更新方式和相关环境因子之间的关系。研究结果表明：林分更新5年后，除了非禾本科杂草功能群外，其他林下植物功能群的物种丰富度均呈现不同程度的增加，但与对照组（砍伐迹地）相比，其差异程度均不显著（P> 0.05）；与对照组相比，藤本和蕨类功能群的相对多度也出现增加趋势，但禾本科草本功能群显著减少（P< 0.05）；木本、藤本和蕨类功能群的相对盖度也呈现增加趋势，但禾本科草本功能群与对照组相比显著减少（P< 0.05）；主成分分析（PCA）发现萌芽更新或植苗更新林的林下植物功能群组成和分布与对照组相比均发生了显著的变异，但不同更新方式（萌芽和植苗）下其林下植物功能群组成和分布差异不明显；通过冗余分析（RDA）确定了冠层透光系数、土壤孔隙度、坡向和土壤氮磷比是影响该林地林下植物功能群的主要因子，它们的叠加效应能解释大于75%的林下植物功能群的变异，最终模型通过排序得到冠层透光系数是影响该林地林下植物功能群的最主要因子。短期的研究发现萌芽和植苗这两种不同的更新方式对桉树林下植物功能群的影响有限，这可能与这两种更新方式形成的林冠结构和土壤理化性质差异性较小有关。
Subjects: Biology >> Botany >> Plant ecology, plant geography submitted time 2016-05-03
Abstract： Aims Our objectives were to study the distribution of soil organic carbon (SOC) density and its influencing factors in main forest ecosystems in Guangxi province. Methods A total of 345 sample plots were established in Guangxi main forest, and the size of each plot was 50 m �20 m. Based on the forest resources inventory data and field investigation, the SOC storage of Guangxi main forest were estimated. The spatial pattern of SOC density was analyzed by the method of geostatistics, and the main influencing factors on SOC density were also explored by principal component analysis and stepwise regression. Important findings The total SOC storage in Guangxi forest was 1686.88 Tg, and the SOC density reached 124.70 Mg/hm2, which is lower than that of China. The best fitted semivariogram model of SOC density was exponential model in Guangxi forest, and had medium spatial autocorrelation. The Kriging contour map indicated that the high value region existed in northeast of Guangxi, and the low value region existed in northwest Guangxi., which manifested as high value in non-karst region and low value in karst region. The SOC density showed difference in five vegetation types and four soil types, following the sequence of bamboo forest > deciduous broadleaf forest > warm coniferous forest > mixed evergreen and deciduous broadleaf forest > evergreen broadleaf forest, and yellow soil > red soil > lateritic red soil > limestone soil. The environment factors including soil depth, longitude, latitude, altitude were the dominant affecting factors of SOC density in Guangxi forest. And the soil depth was the most influential factor, which was attributed to karst landscape.
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