Soil microbes play an important role in the microbial circulation and energy flow of ecosystems. In order to understand the change in the rhizosphere soil microbial community structure and function in the heterogeneous karst habitats, the nutrient content and enzyme activity were analyzed, and Illumina MiSeq high-throughput sequencing technology was used to detect the composition, quantity and functional types of the rhizosphere soil microbial community in Rhododendron pudingense under three kinds of karst microhabitats (soil surface, rock gully and rock surface) in Wangmo Country (WM), Zhenning Country (ZN) and Qinglong Country (QL). The results showed that SS and RG microhabitats had a higher nutrient content and enzyme activity, while RS had the lowest. At the phylum level, Proteobacteria and Actinomycetes were dominant in terms of bacteria, while Ascomycota and Basidiomycotina were dominant in terms of fungi. There was no significant difference in microbial diversity among different karst microhabitats (p > 0.05). At the microbial genus level, there were some differences in species composition among the three karst microhabitats, which may lead to soil heterogeneity in karst microhabitats. WM was a little different from ZN and QL. The results of PCoA showed that the community composition of RG and RS was more similar to that of SS. There was no significant difference in microbial functional types among different microhabitats (p > 0.05). Only the abundance of pathothoph-symbiothoph fungi in RG was significantly higher than that in RS (p < 0.05). The main function of bacteria was metabolism, and saprophytic and symbiotic fungi were the dominant fungal group. In conclusion, soil organic carbon and alkaline phosphatase are important factors affecting the level distribution of microflora in different karst microhabitats. R. pudingense in the SS and RG microhabitats has better soil conditions, which may require protection for the plants in the RS microhabitat. The current study results can provide a theoretical basis for the adaptation mechanism of Rhododendron pudingense to the karst microhabitat.

In the management of eco-tea gardens, the recycling of weathered leaves of the configured tree species plays an important role in the nutrients of the tea garden ecosystem. The in situ decomposition method was used to analyze the decomposition rate, elemental release, and enzymatic activity of different combinations of leaf litter in tea garden soil. The results showed that mixed decomposition accelerates the decomposition turnover period of Jiu’an ecological tea garden. The higher release rate of the litter improved the nutrient effectiveness in the ecological tea garden. The trends of CAT (catalase), AP (acid phosphatase), and PPO (polyphenol oxidase) activities were similar during the decomposition of different mixed leaf litters, while all other enzyme activities showed some differences. There were also some differences in the relationship between the enzyme activity and decomposition rate of leaf litter and the nutrient release rate related to the substrate mass content during the decomposition of leaf litter. Overall, the changes in the nutrient content of the leaf litter during decomposition promoted an increase in enzyme activity, which in turn promoted the release of leaf litter elements, shortened the turnover period of leaf litter decomposition, and accelerated the recycling of elements in the ecological tea garden.

Enzyme stoichiometry can reflect the resource limitation of soil microbial metabolism, and research on the relationships between plants and resource limitation in Karst Microhabitats is scarcely investigated. To clarify the extracellular enzyme stoichiometry characteristics in soil across different karst microhabitats and how the Rhododendron pudingense adapts to nutrient restrictions, plot investigation experiments were set up in Zhenning County, Qinglong County, and Wangmo County of Guizhou Province which included total three karst microhabitats, i.e., soil surface (SS), rock gully (RG), and rock surface (RS), by analyzing he rhizosphere soil nutrient, extracellular enzyme activity, and nutrient content of R. pudingense. The findings indicated that all karst microenvironments experienced varying levels of nitrogen (N) limitation, with the order of N limitation being as follows: SS > RG > RS. Notably, there were significant discrepancies in N content among different plant organs (p< 0.05), with the sequence of N content as follows: leaf > stem > root. However, no significant differences were observed in nutrient content within the same organ across different microenvironments (p > 0.05). A noteworthy discovery was the significant allometric growth relationship between C-P in various organs (p< 0.05), while roots and stems exhibited a significant allometric growth relationship between N-P (p< 0.05). The study highlighted the substantial impact of Total Nitrogen (TN) and N-acquiring enzymes (NAE) on nutrient allocation within the components of R. pudingense. Overall, the research demonstrated that N was the primary limiting factor in the study area’s soil, and R. pudingense’s nutrient allocation strategy was closely associated with N limitations in the karst microenvironment. Specifically, the plant prioritized allocating its limited N resources to its leaves, ensuring its survival. This investigation provided valuable insights into how plants adapt to nutrient restrictions and offered a deeper understanding of soil-plant interactions in karst ecosystems.

(1) Background: In managing ecological tea gardens, litter composed of pruned and fallen tea leaves from companion tree species is an important component of tea garden soil. The decomposition of litter plays a crucial role in regulating nutrient cycling in tea garden ecosystems. (2) Methods: This study employed the litterbag method to investigate chemical stoichiometry characteristics and enzyme activity changes during the decomposition process of pruned and fallen Camellia sinensis leaves from companion tree species in an ecological tea garden located in central Guizhou Province. (3) Results: With decomposition duration, the general trend of changes in the C/N and C/P ratios showed a decrease in the activity of UE (urease), AP (acid phosphatase), and PPO (polyphenol oxidase) followed by an increase, while CAT (catalase) and CEL (cellulase) activity decreased, then increased, and then decreased again. On the other hand, the N/P and the activity of SC (sucrase) first increased and then decreased. The C/N and the activities of UE, PPO, and AP generally reached their maximum values during the late decomposition stage (366–428 d), while the N/P and the CAT activity peaked during the mid-decomposition stage (305 d). In contrast, the activity of SC and CEL reached its maximum value during the early decomposition stage (123 d). The N/P ratios were significantly higher than those of the CS (C. sinensis) litter in the mixed treatment, while C/N and C/P ratios were significantly lower than those in the CS during decomposition for 184–366 days. The UE, CAT, AP, and SC activities of CBL (C. sinensis + B. luminifera) litter were significantly higher than those of the CS litter during decomposition. During the experiment, antagonistic effects were observed in the C/N and C/P ratios of the different litter types. Most mixed litter exhibited additive effects on enzyme activity, while a few showed nonadditive effects. For the nonadditive effects, most were antagonistic effects, mainly in the CPM (C. sinensis + C. glanduliferum) litter. A small portion, mainly observed in the CBL and CCG (C. sinensis + C. glanduliferum) litter, showed synergistic effects. (4) Conclusions: Selecting B. luminifera and C. glanduliferum to be part of the tree species composition in ecological tea gardens can produce positive mixed effects on enzyme activity during litter decomposition, increase nutrient return capacity, maintain tea garden fertility, and achieve the ecological development of tea gardens.

(1) Background: Plant litter decomposition and its effect on soil nutrients are important parts of the ecosystem material cycle, and understanding these processes is key for species selection and allocation, to promote the effective use of litter in ecological tea gardens. (2) Methods: In situ decomposition was used in this study Changes in decomposition rate, element release, and soil properties during the decomposition of the mixed plant residues were measured. (3) Results: The decomposition rate (k) of the CCG (Camellia sinensis + Cinnamomum glanduliferum) mixed plant residue was significantly higher than that of the CS (Camellia sinensis) residue. The decomposition of the CCG, CPM (C. sinensis + Pinus massoniana), and CBL (C. sinensis + Betula luminifera) mixed plant residues showed an additive effect, whereas that of the CCL residue showed an antagonistic effect. The CBL mixed plant residue promoted the release of N; the decomposition of the CCG, CPM, CCL (C. sinensis + Cunninghamia lanceolata), and CBL residues promoted the release of TC (total carbon); and the decomposition of the CCG residue promoted the release of cellulose. After 428 d of decomposition, the four mixed plant residues had improved the soil nutrient contents to some extent. CCG and CBL residue decomposition resulted in greater improvements in soil nutrients. (4) Conclusions: The application of the mixture of material obtained by pruning C. glanduliferum, B. luminifera, and C. sinensis in an ecological tea garden accelerated the decomposition and nutrient release rates, increased soil nutrient contents, shortened the decomposition turnover period of plant residues, and accelerated the nutrient cycle of plant residues in the ecological tea garden.

The functional resemblance structure, which mainly involved the taxonomic and functional β‐diversity, plays a key role in understanding the assembly process during succession in heterogeneous ecosystems. Systematically comparing the functional resemblance structure is essential for uncovering the successional mechanisms since taxonomic and functional β‐diversity co‐vary. In this study, a series of plots were established among the successional stages in a heterogeneous karst forest. The functional resemblance structure was quantified based on the measured plant functional traits to synchronously compare the changes in taxonomic and functional β‐diversity among the successional stages. The results showed that the taxonomic and functional β‐diversity varied asynchronously across the successional stages, reflecting the changes in functional beta redundancy. In addition, the functional local contribution to β‐diversity was higher in the early successional stage. The functional resemblance structure was dominated by functional beta redundancy, with functioning resilience showing an increasing trend during succession, even in the extremely sensitive karst forests. Furthermore, soil properties mainly determined taxonomic β‐diversity while topography primarily affected the functional dimension. Our findings highlighted the importance of functional beta redundancy in determining the functional resemblance structure and emphasized the necessity of synchronous comparison components of the functional resemblance structure when performing the β‐diversity analyses.