Effect of Soil Fertilizer Application on Soil Nutrient Migration and Tea Quality of Plateau-Puerh Tea

In order to solve the problem of chemical fertilizer application balance of Pu’er tea in Taiwan, the effects of different fertilization treatments on land nutrient migration and tea quality were explored, and the basis for rational fertilization of tea gardens was provided. In this study, the effects of different fertilization treatments on tea quality indexes were studied by three different sets of fertilization treatments in tea gardens. Three sets of different fertilization treatments were set up in the experiment: conventional fertilization treatment (T1), slow-release fertilizer reduction by 20% (T2) and slow-release fertilizer reduction by 30% (T3), and the quality index of tea under different fertilization treatments, as well as the alkaline nitrogen, available phosphorus and total nitrogen and total phosphorus content in surface water of the soil were measured and analyzed. The results showed that: 1) compared with T1, the soil available phosphorus in T3 decreased by 23.5%, and the alkalinelyzed nitrogen increased by 20.5%;2) compared with T1, the total nitrogen and total phosphorus concentrations of surface water in the T2 and T3 treatments were at a low level compared with T1;compared with T1, T2 decreased by 71.4%, and T3 decreased by 68.6%;3) compared with T1, T3 was able to maintain the quality indicators of amino acids, tea polyphenols and soluble sugars in tea in a high and stable range. Therefore, under the condition of conventional fertilization and reduction, a 30% reduction in slow-release fertilizer is currently more suitable for the fertilization technology of Menghai County Tea Garden.

Correlation and Pathway Analysis of the Carbon,Nitrogen,and Phosphorus in Soil-Microorganism-Plant with Main Quality Components of Tea(Camellia sinensis)

The contents of carbon(C),nitrogen(N),and phosphorus(P)in soil-microorganisms-plant significantly affect tea quality by altering the main quality components of tea,such as tea polyphenols,amino acids,and caffeine.However,few studies have quantified the effects of these factors on the main quality components of tea.The study aimed to explore the interactions of C,N,and P in soil-microorganisms-plants and the effects of these factors on the main quality components of tea by using the path analysis method.The results indicated that(1)The contents of C,N,and P in soil,microorganisms,and tea plants were highly correlated and collinear,and showed significant correlations with the main quality components of tea.(2)Optimal regression equations were established to esti-mate tea polyphenol,amino acid,catechin,caffeine,and water extract content based on C,N,and P contents in soil,microorganisms,and tea plants(R^(2)=0.923,0.726,0.954,0.848,and 0.883,respectively).(3)Pathway analysis showed that microbial biomass phosphorus(MBP),root phosphorus,branch nitrogen,and microbial biomass carbon(MBC)were the largest direct impact factors on tea polyphenol,catechin,water extracts,amino acid,and caffeine content,respectively.Leaf carbon,root phosphorus,and leaf nitrogen were the largest indirect impact factors on tea polyphenol,catechin,and water extract content,respectively.Leaf carbon indirectly affected tea polyphenol content mainly by altering MBP content.Root phosphorus indirectly affected catechin content mainly by altering soil organic carbon content.Leaf nitrogen indirectly affected water extract content mainly by altering branch nitrogen content.The research results provide the scientific basis for reasonable fertilization in tea gardens and tea quality improvement.

Evaluation and Analysis for Survey of Tea Production Quality Safety Management and Control

[Objectives]This study was conducted to investigate and evaluate the quality safety of tea production in China.[Methods]With the production of famous and high-quality green tea in the western Sichuan tea areas as the investigation object,the practice survey and comprehensive evaluation analysis method were adopted to conduct research on tea production quality safety management and control,and a comprehensive evaluation was carried out in combination with the survey.[Results]Statistical analysis and scoring were carried out according to relevant indices,and the current situation of tea production quality safety was comprehensively evaluated.Four hazards were found,including pesticide residues,heavy metal residues,harmful microorganisms and non-tea impurities,and improvement measures were proposed.[Conclusions]This study provides a theoretical reference for improving the quality safety of tea production in China.

Study on Rational Fertilization Scheme for Mulberry(Morus alba Linn) Used for Tea

[Objective] This study was conducted to investigate effects of application amounts of N, P and K and their ratio on tea quality components in mulberry leaves. [Method] Effects of sole application and combined application of N, P and K on the yield and tea quality components of spring mulberry leaves were studied by 3-factor 3-level experiment, based on previous experiments. [Result] Combined ap- plication of 3 of N, P and K was better than sole application and combined appli- cation of 2 from them. Insufficient or excessive fertilization both significantly reduced yield of mulberry leaves and contents of tea quality components, such as 1-de- oxynojimycin （DNJ）, flavonoids, tea polyphenols and amino acids. With the yield of spring mulberry leaves as a target, it is advised to apply N, P and K at rates of 240, 150 and 60 kg/hm^2 , respectively. [Conclusion] This study provides reference and theoretical basis for the establishment of raw material base of high-quality mul- berry tea.

Analysis on the Characters of Dark Tea in Different Producing Areas Based on Sensory Evaluation

Sensory evaluation is an important way for evaluating the quality of tea.By sensory evaluation,we can judge and identify the quality,distinguish the types,and characterize unique qualities of dark tea,in order to offer technical guidance for producers and give references to consumers.In this paper,we mainly summarized the requirements and methods of dark tea evaluation,expounded the characteristics in main producing areas,and analyzed the key process characteristics and the main technology that affecting the quality formation of dark tea.

Biochar addition to tea garden soils:effects on tea fluoride uptake and accumulation

Long-term consumption of tea with high fluoride(F)content has a potential threat to human health.The application of different amounts of biochar to reduce F accumulation in tea leaves has been little studied.In this study,a pot experiment was conducted to investigate the effect of biochar amounts(0,0.5%,2.5%,5.0%,8.0%,and 10.0%,w/w)on tea F content during the tea plant growth.Changes in tea quality,soil F fraction,and soil properties caused by biochar and the relationship with tea F accumulation were also considered.The results showed that the application of biochar amendment significantly reduced water-soluble F contents in tea leaves compared to CK(without biochar),especially in the 8.0%treatment(72.55%).Overall,biochar contributed to improving tea polyphenols and caffeine,but had no significant impact on free amino acids and water leachate.Compared with CK,5.0-10.0%biochar significantly increased soil water-soluble F content due to the substitution of F−with OH−under high pH.Additionally,biochar applied to tea garden soil was effective in decreasing the soil exchangeable aluminum(Ex-Al)content(46.37-91.90%)and increasing the soil exchangeable calcium(Ca^(2+))content(12.02-129.74%)compared to CK,and correlation analysis showed that this may help reduce F enrichment of tea leaves.In general,the application of 5.0-8.0%biochar can be suggested as an optimal application dose to decrease tea F contents while simultaneously improving tea quality.

The Reference Genome of Tea Plant and Resequencing of 81 Diverse Accessions Provide Insights into Its Genome Evolution and Adaptation

Tea plant is an important economic crop,which is used to produce the world's oldest and most widely consumed tea beverages.Here,we present a high-quality reference genome assembly of the tea plant(Camellia sinensis var.sinensis)consisting of 15 pseudo-chromosomes.LTR retrotransposons(LTR-RTs)account for 70.38%of the genome,and we present evidence that LTR-RTS play critical roles in genome size expansion and the transcriptional diversification of tea plant genes through preferential insertion in promoter regions and introns.Genes,particularly those coding for terpene biosynthesis pro-teins,associated with tea aroma and stress resistance were significantly amplified through recent tandem duplications and exist as gene clusters in tea plant genome.Phylogenetic analysis of the sequences of 81 tea plant accessions with diverse origins revealed three well-differentiated tea plant populations,support-ing the proposition for the southwest origin of the Chinese cultivated tea plant and its later spread to western Asia through introduction.Domestication and modern breeding left significant signatures on hundreds of genes in the tea plant genome,particularly those associated with tea quality and stress resis-tance.The genomic sequences of the reported reference and resequenced tea plant accessions provide valuable resources for future functional genomics study and molecular breeding of improved cul-tivars of tea plants.