Lushan Yunwu tea quality is limited by soil acidity and sterility. This article examined a 3-year localization experiment at 1100 m altitude to demonstrate the sustainable management of conditioners, calcium magnesium phosphate (P), rapeseed cake (C), and combination application (P + C) by one-time application on the soil-tea system in Mount Lushan. The study found that conditioners (P, C, P + C) reduced soil acidification and maintained a pH of 4.75-5.34, ideal for tea tree development for 3 years. Phosphorus activation coefficient (PAC), nitrogen activation coefficient (NAC), and organic matter (OM) content were significantly higher (P < 0.05) in the first year after conditioner treatment, with P + C being the best. After P + C, PAC, NAC, and OM rose by 31.25%, 47.70%, and 10.06 g kg-1 compared to CK. In comparison to the CK, tea\'s hundred-bud weight (BW), free amino acids (AA), tea polyphenols (TPC), and chlorophyll (Chl) content of P + C treatment got 29.98%, 14.41%, 22.49%, and 28.85% increase compared to that of the CK, respectively. In the second year, the three treatments of P, C and P + C still had significant moderating effects on the physicochemical properties of the soil and the quality indexes of the tea leaves. The PAC of the soil under the three treatments increased by 0.06%, 0.07% and 0.18%, respectively, as compared to the control.P + C increased BW, AA, TPC and Chl of tea for 2 years. Three conditioners had 2-year regulatory impacts on soil fertility indicators, tea output, and quality. C and P + C both increased soil OM by 18.59% and 21.78% compared to CK in the third year, outperforming P treatment. Redundancy analysis revealed that the primary physicochemical factors influencing tea output and quality were soil OM and pH, with available phosphorus, urease, acid phosphatase, and available nitrogen following closely afterwards.

The relationship between the chemical composition and quality of Lushan Yunwu tea (LYT) from different geographical origins is not clear. Sensory evaluation, metabolomics analyses combined with chemometrics were conducted on LYT from 8 different geographical origins, and altitude was identified as the main factor responsible for the differences among LYT. A total of 32 non-volatile and 27 volatile compounds were identified as marker metabolites to distinguish the origins of high altitudes from those of low altitudes. LYT samples from higher altitude areas contained more free amino acids, sugars, and organic acids, and less catechins, which may contribute to the reduction of bitterness and astringency and the enhancement of umami. The contents of geranylacetone, ethyl hexanoate, ethyl caprylate, 3-carene, d-cadinene, linalool, nerol, and nerolidol in high altitude areas were higher than those in low altitude areas, indicating that LYT from high altitude had strong floral and fruity aroma. The altitudes were positively correlated with pH value, total flavonoids, soluble protein, total free amino acids, and the antioxidant capacities of the LYT. This study provided a theoretical basis for the study of the effect of altitude on tea quality.

Lushan Yunwu tea (LSYWT) is a famous green tea in China. However, the effects of intercropping tea with flowering cherry on the overall aroma of tea have not been well understood. In this study, headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used for analysis. A total of 54 volatile compounds from eight chemical classes were identified in tea samples from both the intercropping and pure-tea-plantation groups. Principal component analysis (PCA), orthogonal partial least-squares discriminant analysis (OPLS-DA), and odor activity value (OAV) methods combined with sensory evaluation identified cis-jasmone, nonanal, and linalool as the key aroma compounds in the intercropping group. Benzaldehyde, α-farnesene, and methyl benzene were identified as the main volatile compounds in the flowering cherry using headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS). These findings will enrich the research on tea aroma chemistry and offer new insights into the product development and quality improvement of LSYWT.

Lushan Yunwu Tea is one of a unique Chinese tea series, and total polyphenols (TP), free amino acids (FAA), and polyphenols-to-amino acids ratio models (TP/FAA) represent its most important taste-related indicators. In this work, a feasibility study was proposed to simultaneously predict the authenticity identification and taste-related indicators of Lushan Yunwu tea, using near-infrared spectroscopy combined with multivariate analysis. Different waveband selections and spectral pre-processing methods were compared during the discriminant analysis (DA) and partial least squares (PLS) model-building process. The DA model achieved optimal performance in distinguishing Lushan Yunwu tea from other non-Lushan Yunwu teas, with a correct classification rate of up to 100%. The synergy interval partial least squares (siPLS) and backward interval partial least squares (biPLS) algorithms showed considerable advantages in improving the prediction performance of TP, FAA, and TP/FAA. The siPLS algorithms achieved the best prediction results for TP (RP = 0.9407, RPD = 3.00), FAA (RP = 0.9110, RPD = 2.21) and TP/FAA (RP = 0.9377, RPD = 2.90). These results indicated that NIR spectroscopy was a useful and low-cost tool by which to offer definitive quantitative and qualitative analysis for Lushan Yunwu tea.