In order to fully comprehend the impact of soil acidification on the quality of tea, further analyses are essential and are of the utmost importance to the cultivation of tea trees and the simultaneous enhancement of tea quality. In May 2022, Tieguanyin tea trees planted in soils with different pH levels were selected as the research object of this study to analyze the effect of soil pH on the soil chemical index, soil fertility and the aroma quality of tea leaves. The results showed that the organic matter content, cation exchange capacity and the available nitrogen, available phosphorus and available potassium contents in the rhizosphere soil of the tea trees decreased significantly with decreasing soil pH levels (5.32–3.29), while the total nitrogen, total phosphorus and total potassium contents did not change significantly. The results of an aroma quality analysis showed that the aroma of the Tieguanyin tea was mainly floral, and the formation of floral odor characteristics was mainly derived from geraniol. The results of an interaction network analysis showed that the soil chemical indexes were significantly positively correlated with geraniol and floral aromas except for the total phosphorus and total potassium contents. In conclusion, with a decrease in the pH of soil, the soil’s cation exchange capacity, organic matter content and available nutrient content showed decreasing trends which, in turn, hindered the synthesis of geraniol and reduced the floral odor characteristics of tea leaves.

Background: Exploring the spatial and temporal evolution patterns of regional ecosystem service functions and their main drivers can provide effective support for formulating regional ecological conservation policies and coordinating sustainable economic–ecological development. Methods: This study quantifies the service functions of the water production, soil conservation, carbon storage, habitat quality, and net primary productivity (NPP) in the study area based on the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model and the Carnegie–Ames–Stanford Approach (CASA) model and constructs a comprehensive index for ecosystem services (CES) based on the analytic hierarchy process (AHP) to reflect the total supply of various ecosystem services spatially and explore the main driving mechanisms of their spatial variation. The main driving mechanisms of the spatial variation were investigated. Results: (1) Water production in the study area from 2010 to 2020 showed a trend of increasing before decreasing, soil retention showed a trend of continuously decreasing, carbon storage and biotope quality showed a trend of decreasing before increasing, and the NPP showed a trend of continuously increasing. (2) The mean CES of the study area from 2010 to 2020 (0.5398, 0.5763, 0.5456) showed a trend of increasing before decreasing. The improvement areas were mainly concentrated in the western, southwestern, and northeastern parts of the study area, and the degraded areas were mainly distributed in the southeast and northwest. (3) The fit of the geographically weighted regression (GWR) was higher than that of the ordinary least squares (OLS) in all the periods, and the main driving factors affecting the spatial variation in the CES were the NDVI and tea plantation area (T-Area). Conclusion: This study constructed the CES model, explored the regional CES spatiotemporal evolution pattern and its main driving mechanism, and provided a reference basis for promoting the high-quality development of specialized tea regions.

The expansion of tea plantations has caused changes in land use structure, which, in turn, has affected the regional habitat quality. Exploring the characteristics of changes in land use structure and habitat quality under different development scenarios is important for the formulation of regional land planning policies and the guarantee of ecological security. This study quantified the habitat quality of the study area from 2010 to 2020 based on the InVEST habitat quality module and explored the land use distribution patterns and habitat quality change characteristics under different scenarios in combination with the PLUS model. The results show that, from 2010 to 2020, the area of tea plantations expanded by 153.0126 km², and the mean value of habitat quality increased from 0.6502 to 0.6919; in different development scenarios, the area of tea plantations was from large to small in the order of scenario 1 (871.2468), scenario 3 (599.4531) and scenario 2 (518.5440), and the mean value of habitat quality was from high to low in the order of scenario 1 (0.7385), scenario 2 (0.7162) and scenario 3 (0.6919). This study mainly explored the structural changes of land use and habitat quality evolution characteristics under different development scenarios in the study area, and the results of the study can provide a reference basis for rational land development and utilization and habitat conservation in the large-scale tea plantation area.

Continuous monoculture affects elemental uptake in Casuarina equisetifolia ( C. equisetifolia ). In this study, C. equisetifolia with different numbers of continuous plantings was used to determine multi-element contents in rhizosphere soil, roots, and leaves using inductively coupled plasma-mass spectrometry (ICP-MS), and to assess the physiological indices of the roots and leaves. The effects of continuous planting on the uptake and transport of elements, and physiological characteristics of C. equisetifolia were also analyzed. The results showed that continuous planting of C. equisetifolia significantly reduced the enrichment capacity of its roots and leaves for certain elements. Specifically, continuous planting reduced Na and Ni enrichment in roots and N, K, Mg, Lu, Rb, and Zn enrichment in leaves. In terms of elemental transport, continuous planting resulted in a significant decrease in the transport of Mo, N, Nb, and Sr by C. equisetifolia . Physiological indice results showed that root activity, root cation exchange capacity, chlorophyll content, and net photosynthetic rate in C. equisetifolia tended to decrease significantly with an increase in the number of continuous plantings. In conclusion, continuous planting reduced the uptake, enrichment, and transport of beneficial elements in C. equisetifolia , which in turn inhibited root growth, decreased photosynthetic capacity, and ultimately stunted plant growth. This study provides an important reference for planting management and elemental regulation in continuous planting systems of C. equisetifolia .

Mineral elements affect tea nutritional and flavor quality, but systematic research on their dissolution behavior and links to volatile and taste profiles in Dahongpao tea is lacking, as is evidence regarding contribution to mineral intake for different populations. In this study, nine Dahongpao teas were brewed five times. Eleven elements were measured by inductively coupled plasma mass spectrometry (ICP-MS) with first-order kinetic fitting; volatile profiles were analyzed by electronic nose and taste attributes by electronic tongue; the contribution of tea infusions to dietary reference intakes was estimated from Chinese Dietary Reference Intakes (2023). The results showed that electronic nose analysis revealed distinct variation in volatile compound classes among the nine samples, with broad range and sulfur–organic compounds showing the highest response intensities. Electronic tongue analysis showed clear differences in taste profiles, particularly in astringency, umami, and sweetness, across the nine samples. Regarding dissolution behavior, Mg had the highest dissolution rate (67.24–70.94%), while Fe, Ca, K, and Zn were below 10%; dissolution followed first-order kinetics and total dissolved amounts correlated with total contents except for Fe. Network analysis integrating element data with volatile and taste profiles demonstrated that Mg and Mo contents were positively correlated with multiple volatile classes (e.g., sulfur–organic, broad range), while Ca, Mg, and Fe dissolution rates significantly correlated with richness and aftertaste-A, and Mo inversely correlated with sourness and saltiness. Contribution assessment showed that only Ca, K, Mg, and Se could be marginally supplemented, but the tea amounts needed far exceeded typical intake. In summary, element dissolution in Dahongpao tea is co-regulated by brew count and total content, with complex element–flavor interactions. Tea is not a primary mineral source; consumption should be individualized by age and physiological status.