Tea-producing Areas Research Articles

Whole-genome resequencing reveals the origin of tea in Lincang.

Phylogeographic, population genetics and diversity analysis are crucial for local tea resource conservation and breeding programs. Lincang in Yunnan has been known as the possible place of domestication for tea worldwide, yet, its genetic makeup and unique Lincang origin are little understood. Here, we reported a large-scale whole-genome resequencing based population genomic analysis in eight main tea-producing areas of Lincang in Yunnan (1,350 accessions), and the first comprehensive map of tea genome variation in Lincang was constructed. Based on the population structure, tea sample in Lincang was divided into three subgroups, and inferred Xigui and Nahan Tea Mountain in Linxiang, Baiying Mountain Ancient Tea Garden in Yun, and Jinxiu Village of Xiaowan Town in Fengqing, which belong to the birthplace of the three subgroups, were all likely to be the origin center of Lincang tea. Meanwhile, the history population sizes analysis show that similar evolutionary patterns were observed for the three subgroups of Lincang. It also was observed that the hybrid among eight areas of Lincang was noticeable, resulting in insignificant genetic differentiation between geographical populations and low genetic diversity. The findings of this study clarified the genetic make-up and evolutionary traits of the local population of tea, which gave some insight into the development of Lincang tea.

Dynamic Changes of Volatile Compounds during the Xinyang Maojian Green Tea Manufacturing at an Industrial Scale.

Xinyang Maojian (XYMJ) is one of the premium green teas and originates from Xinyang, which is the northernmost green tea production area in China. The special geographic location, environmental conditions, and manufacturing process contribute to the unique flavor and rich nutrition of XYMJ green tea. Aroma is an important quality indicator in XYMJ green tea. In order to illustrate the aroma of XYMJ green tea, the key odorants in XYMJ green tea and their dynamic changes during the manufacturing processes were analyzed by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). A total of 73 volatile compounds of six different chemical classes were identified in the processed XYMJ green tea samples, and the manufacturing processes resulted in the losses of total volatile compounds. Among the identified volatile compounds, twenty-four aroma-active compounds, such as trans-nerolidol, geranylacetone, nonanal, (+)-δ-cadinene, linalool, (Z)-jasmone, cis-3-hexenyl butyrate, cis-3-hexenyl hexanoate, methyl jasmonate, and β-ocimene, were identified as the key odorants of XYMJ green tea based on odor activity value (OAV). The key odorants are mainly volatile terpenes (VTs) and fatty acid-derived volatiles (FADVs). Except for (+)-δ-cadinene, copaene, cis-β-farnesene, (Z,E)-α-farnesene and phytol acetate, the key odorants significantly decreased after fixing. The principal coordinate analysis (PCoA) and the hierarchical cluster analysis (HCA) analyses suggested that fixing was the most important manufacturing process for the aroma formation of XYMJ green tea. These findings of this study provide meaningful information for the manufacturing and quality control of XYMJ green tea.

MiR319a targeting of CsTCP10 plays an important role in defense against gray blight disease in tea plant (Camellia sinensis).

Gray blight disease occurs widely in major tea-producing areas and harms the leaves of tea trees, which affects the quality and yield of processed tea. According to an analysis of previous sequencing data, miR319a may be important in the resistance of tea plants to gray blight disease. In this study, based on 5'RLM-RACE, qRT-PCR, sODN, CIN and transient transformation experiments in tobacco, CsTCP10 and CsTCP4 were found to be cleaved by miR319a. qRT-PCR and northern blotting also revealed that the expression pattern of CsTCP10 in tea leaves was opposite to that of miR319a, while that of CsTCP4 displayed no similar change. Furthermore, a large amount of reactive oxygen species was found to accumulate in tea leaves in the antisense oligodeoxynucleotide experiment, while the expression of CsTCP10 was inhibited. These results suggest that CsTCP10 is a positive regulator of the resistance of tea plants to gray blight disease. Compared with the wild-type, the expression of AtTCP10 in transgenic Arabidopsis plants was downregulated. After infection with the pathogen, the transgenic plants were more severely damaged. Our results suggest that miR319a facilitates Pestalotiopsis infection by suppressing the expression of CsTCP10 in tea plants.

The Role of Japanese Tea Cafes in Ise Tea Production Area

The Role of Japanese Tea Cafes in Ise Tea Production Area

Population Structure Analysis and Genome-Wide Association Study of Tea (Camellia sinensis (L.) Kuntze) Germplasm in Qiannan, China, Based on SLAF-Seq Technology

Duyun Maojian tea is a famous tea in China. In this study, the specific-locus amplified fragment (SLAF) sequencing method was used to analyze the population structure and conduct a genome-wide association study (GWAS) of 2 leaf traits of 123 tea plants in Qiannan, China. A total of 462,019 SLAF tags and 11,362,041 single-nucleotide polymorphism (SNP) loci were obtained. The results of phylogenetic tree analysis, cluster analysis, and principal component analysis showed that 123 tea germplasms were clustered into three groups, and the heterozygosity rates for Groups I, II, and II were 0.206, 0.224, and 0.34, respectively. Generally, tea germplasms in a production area are clustered in a group, indicating that tea germplasms in different production areas have certain genetic diversity. The traditional Duyun Maojian tea core production areas, TS and DC-SJ, are clustered into Group I and Group II respectively, while the ZY production area is relatively independent in Group III. Furthermore, based on GWAS analysis, 11 candidate genes related to leaf apex and 7 candidate genes related to leaf shape were obtained. This study clarified the genetic relationship among eight Duyun Maojian tea production areas and obtained candidate genes related to leaf apex and leaf shape development. The results showed that population structure and candidate genes are an effective basis for the breeding of Duyun Maojian tea germplasm.

Applying Nutrient Expert system for rational fertilisation to tea (Camellia sinensis) reduces environmental risks and increases economic benefits

The overuse and unbalanced application of fertilisers have become common practices in the modern world, causing serious environmental problems and restricting tea growth and quality. Therefore, a scientific and rational fertilisation recommendation method should be developed to solve these problems. In this study, fertilisation datasets collected from field experiments (n = 548) in tea-producing areas (n = 21) from 2016 to 2020 were used to build (n = 492) and validate (n = 56) the Nutrient Expert (NE) system for tea. The field validation results indicated that the NE system significantly increased tea yield, quality, economic benefits, and nitrogen (N) use efficiency, as well as decreased greenhouse gas (GHG) emissions. Compared with current farmers’ practice (FP), NE reduced fertiliser-sourced N, phosphorus (P), and potassium (K) application rates by 28%, 25%, and 20%, respectively. On average, NE increased tea yields by 14.0% and 9.3% relative to FP and soil testing (ST). The total concentration of free amino acids, which is one of the most important indexes of green tea quality, were highest in the NE treatment. The net economic benefits of NE increased by 20.0% and 12.6% relative to FP and ST. NE also increased the N utilisation efficiency of tea shoots by 87.0% and 85.3% compared to FP and ST, respectively. Moreover, NE reduced total GHG emissions by 27.7% and 9.6% compared to FP and ST. These results suggest that fertiliser recommendations based on the NE system can increase economic benefits and reduce environmental risks by avoiding excessive fertilisation to maintain sustainable agriculture.

Rare Bacteria Assembly in Soils Is Mainly Driven by Deterministic Processes.

Rare species are crucial components of the highly diverse soil microbial pool and over-proportionally contribute to the soil functions. However, much remains unknown about their assembling rules. The biogeographic patterns and species aggregations of the rare bacterial biosphere were assessed using 140 soil samples from a gradient of 2000 km across the main tea-producing areas in China. About 96% OTUs with ~40% sequences were classified as rare taxa. The rare bacterial communities were significantly affected by geographical regions and showed distance-decay effects, indicating that the rare bacteria are not cosmopolitan, they displayed a pattern of limited dispersal and were restricted to certain sites. Variation partitioning analysis (VPA) revealed that environmental variation and spatial factors explained 12.5% and 6.4%, respectively, of the variance in rare bacterial community. The Mantel and partial Mantel tests also showed that the environmental factors had stronger (~3 times) impacts than spatial factors. The null model showed that deterministic processes contributed more than stochastic processes in rare bacterial assembly (75% vs. 25%). There is likely an enrichment in ecological functions within the rare biosphere, considering this high contribution of deterministic processes in the assembly. In addition, the assembly of rare taxa was found to be mainly driven by soil pH. Overall, this study revealed that rare bacteria were not cosmopolitan, and their assembly was more driven by deterministic processes. These findings provided a new comprehensive understanding of rare bacterial biogeographic patterns and assembly rules.

Non-targeted and targeted metabolomics profiling of tea plants (Camellia sinensis) in response to its intercropping with Chinese chestnut

BackgroundIntercropping is often used in the tea producing areas where land resources are not so abundant, and the produced green tea is tasted more delicious through a tea-Chinese chestnut intercropping system according to the experience of indigenous farmers. The length and weight of tea leaf increase under this intercropping system and their root systems are stratified vertically and coordinate symbiosis. However, the delicacy mechanism under the intercropping is not fully understood.ResultsGreen tea from the Chinese chestnut–tea intercropping system established in the 1980s ranked highest compared with a pure tea plantation from the same region. Based on the non-targeted metabolomics, 100 differential metabolites were upregulated in the tea leaves from intercropping system relative to monoculture system. Twenty-one amino acids were upregulated and three downregulated in response to the intercropping based on the targeted metabolomics; half of the upregulated amino acids had positive effects on the tea taste. Levels of allantoic acid, sugars, sugar alcohols, and oleic acid were higher and less bitter flavonoids in the intercropping system than those in monoculture system. The upregulated metabolites could promote the quality of tea and its health-beneficial health effects. Flavone and flavonol biosynthesis and phenylalanine metabolism showed the greatest difference. Numerous pathways associated with amino acid metabolism altered, suggesting that the intercropping of Chinese chestnut–tea could greatly influence amino acid metabolism in tea plants.ConclusionsThese results enhance our understanding of the metabolic mechanisms by which tea quality is improved in the Chinese chestnut–tea intercropping system and demonstrate that there is great potential to improve tea quality at the metabolomic level by adopting such an intercropping system.

Impact of Farmers’ Associations on Household Income: Evidence from Tea Farms in Vietnam

Farmers’ associations play an important role to help members increase their access to supports of information, capital, and technology; bring benefits to members; and partly promote production, enhance productivity, and increase income. This paper systematizes the theoretical foundation and empirical evidence on income difference between the member and non-member farmers and identifies factors that affect their decisions to join associations. By comparing specific characteristics between the member and non-member farmers, the paper examines the impact of joining farmers’ associations on the income of tea farmers in Vietnam by using the data from the survey of 742 farms. In our sample, 376 respondents are members and 366 non-members of associations in the four largest tea-producing areas, which cover 30 provinces in Vietnam. The paper uses OLS regression model to identify the factors that influence the decision of tea farms to join farmers’ organizations and tobit model to assess more detailed impacts of membership on income. The findings show that the farmers, who are members of an association, are more helpful in the ability to access better market services and more tea prices, and are more likely to earn a higher average income than those are non-members. Moreover, their memberships result in an increase of 0.166 unit of income. The research results also show that other factors, including labor, tea price, share of tea sold, farmer age, tea area, ability to access extension services, and credit services, affect the farmer’s income.

Food traceability system awareness and agricultural operation: A Study of tea farms in Fujian, China

China is establishing a Food Traceability System (FTS), but the policy implementation is behind most developed countries. The lack of FTS awareness may be a factor contributing to farming practices that are not consistent with FTS policies. Furthermore, the structure of an agri-food supply chain is a factor influencing farms’ compliance with FTS. The present study focuses on pesticide residue control and traceability issues in one of the largest tea production areas in China. It aims to examine the effect of FTS awareness and related policies on tea farms’ operations as well as the influences of supply chain structure on the effects of policy awareness.In this study the data were collected from Fujian province, which is a traditional, major tea-growing region in China with 18% of national production. Farms were recruited through a Stratified Sampling procedure that included 428 participating farms from the four largest tea-producing counties in Fujian. The participating farms answered questions regarding their awareness of FTS and related policies as well as the supply chain structure. The participants also reported their agricultural record-keeping practices related to pesticide residue control, including pesticide use, pesticide residue test, and sales record.The results reveal that farm owners’ or operators’ FTS awareness has a positive effect on pesticide use and sales record-keeping practice, and the supply chain structure importantly moderates the effects of policy awareness on operations related to pesticide residue control. Compared to independent growers, tea farms within an integrated supply chain were more likely to take pesticide residue tests or keep sales records. The results suggest that increasing FTS awareness among tea growers would be crucial to establish a safe and traceable system. Furthermore, governments need to take the supply chain structure into account.

Influence of Topographical Factors on Spatial Distribution Characteristics of Soil Nutrients in Qinba Mountain Area

To study the spatial distribution characteristics of soil nutrients in different micro-topography and their correlation with topographic factors, to provide reference basis for soil resource nutrient management and ecological environment construction in other areas with the same topography. This paper is based on 150 soil samples from 3 main tea-producing areas in Shangnan County, and analysis methods such as sampling analysis of variance and correlation analysis are applied to soil organic matter, total nitrogen, available potassium, and available effects under different micro-topography (slope, aspect, and slope position). The spatial distribution characteristics of phosphorus were analyzed and the correlation between soil nutrients and topographic factors was explored. The results showed that the contents of soil organic matter, total nitrogen, available phosphorus and available potassium in the surface layer (0-10cm) of the study area were significantly higher than those in the middle and lower layers of soil, all of which were of moderate intensity variation. Soil total nitrogen, available potassium, available phosphorus and organic matter content are affected to some extent by slope, aspect and slope position. In general, soil total nitrogen, organic matter content and slope position are significantly negatively correlated (P <0.05), and the slope direction showed a very significant positive correlation (P <0.01), while the soil available potassium and available phosphorus had a negative correlation with the slope position and slope (P <0.05).

Determination of 9,10-anthraquinone in tea consumed in Shandong Province of China

In this study, 170 tea samples were investigated for the occurrence of 9,10-anthraquinone (AQ), which was collected from Shandong Province of China in 2018. The contamination levels of AQ were detected by a combination of QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure with gas chromatography tandem mass spectrometry. Under the optimal conditions, the linear range for AQ was from 10 to 200 ng/mL. The recoveries ranged from 95.6% to 101%, with the coefficient of variation less than 3.99%. The limits of detection and quantification for AQ were 0.001 and 0.003 mg/kg, respectively. Owing to the good accuracy, precision, and high sensitivity, the proposed method is suitable for the determination of trace AQ in tea. The results demonstrated that AQ was detected in 67.1% of tea samples, with the average concentration of 0.0160 mg/kg. The contamination levels varied from tea types and sale locations. The individual average values of AQ in green tea, black tea, oolong tea, and pu-erh tea products were 0.0161 mg/kg, 0.0140 mg/kg, < 0.003 mg/kg and 0.0337 mg/kg, respectively. The level of AQ contamination in a descending order was wholesale markets, supermarkets, specialty stores, and production bases. In addition, the influence of different tea-producing areas on AQ contamination level in Shandong Province was investigated. Contamination levels of AQ did not show significant correlation with the producing areas in Shandong. Although a high incidence of AQ contamination was detected in tea samples, the total average value meets the maximum limit of the European Union (0.02 mg/kg).

Temporal variation in nutrient requirements of tea (Camellia sinensis) in China based on QUEFTS analysis

Fertilisation datasets collected from field experiments (n = 21) in tea-producing areas from 2016 to 2018 were used to build a quantitative evaluation of the fertility of tropical soils (QUEFTS) model to estimate nutrient uptake of tea plants, and to investigate relationships between tea yield and nutrient accumulation. The production of 1000 kg spring tea (based on one bud with two young expanding leaves) required 12.2 kg nitrogen (N), 1.2 kg phosphorus (P), and 3.9 kg potassium (K), and the corresponding internal efficiencies (IEs) for N, P, and K were 82.0, 833.3, and 256.4 kg kg−1. To produce 1000 kg summer tea, 9.1 kg N, 0.8 kg P, and 3.1 kg K were required, and the corresponding IEs for N, P, and K were 109.9, 1250.0, and 322.6 kg kg−1. For autumn tea, 8.8 kg N, 1.0 kg P, and 3.2 kg K were required to produce 1000 kg tea, and the corresponding IEs for N, P, and K were 113.6, 1000.0, and 312.5 kg kg−1. Field validation experiments performed in 2019 suggested that the QUEFTS model can appropriately estimate nutrient uptake of tea plants at a certain yield and contribute to developing a fertiliser recommendation strategy for tea production.

A new stunt nematode, Geocenamus chengi n. sp. (Nematoda: Merliniinae) in the rhizosphere of tea (Camellia sinensis) from Zhejiang Province, China.

The tea plant is native to China; the country has the greatest tea production areas in the world. In an attempt to investigate the nematode biodiversity associated with the tea plantations of Hangzhou, Zhejiang Province, a population of stunt nematode was detected. This group of nematodes is comprised of migratory ecto-parasites of roots and can subsist on a variety of host plants. Therefore, the detected population was studied carefully using the integrative taxonomy approach and identified as a new species of genus Geocenamus. Geocenamus chengi n. sp. can be characterized by females having six incisures in the lateral field; labial region is dome shaped and slightly offset from the rest of the body having four to five annuli; head framework is weakly developed; deirids are absent; excretory pore is located at the anterior region of basal pharyngeal bulb. Under SEM, the vulva is a transverse slit, vulval lips are elongated and ellipsoidal with epiptygma. The tail is annulated, elongated, and conical having bluntly pointed tip and a terminal hyaline region that forms 21 to 33% of the tail length. Spicule is 22 to 25 μm long, gubernaculum is saucer shaped; bursa is crenated covering the tail until the hyaline tail region. Morphologically, the species is close to G. circellus, G. joctus, G. loofi, G. ordinarius, G. processus, G. tetyllus, and G. tortilis. Phylogenetic relationships of the new species based on D2-D3 expansion domains of 28 S, ITS, and 18 S rRNA genes indicated that G. chengi n. sp. clustered in a separate clade with G. vietnamensis.

Tea Production in Japan and in the World

Tea is one of the most popular beverages worldwide. Tea (Camellia sinensis) belongs to the genus Camellia. C. sinensis has two varieties, sinensis and assamica. Tea is thought to have originated in Yunnan Province of China. The total amount of tea production in the world was 5,812,000 t in 2017. China was the largest tea producer and India was the second-largest producer. Indonesia was in sixth place and Japan was in ninth place. The custom of drinking tea was introduced into Japan from China in the early part of the eighth century. Tea plants had been introduced to Japan a little before then. Japanese native tea plants belong to C. sinensis var. sinensis. The total tea production area in Japan in 2018 was 41.500 ha, and total amount of tea production in Japan in 2018 was 81,500 t. Most of the tea produced in Japan is steamed green tea. Some types of microbiological fermentation tea are produced in mountainous areas. These teas are similar to teas produced in Yunnan province and the surrounding areas. Small-scale black tea production has recently been increasing. In 2016, the total amount of revenue from tea production in Japan was 96 billion yen (827 million dollars), accounting for 1% of the total revenue from agricultural production. Fertilizer costs accounted for 30% of the total production costs. Since amino acid gives green tea a sweet and brothy taste, more than 500 kg per ha of nitrogen fertilizer has been applied to tea fields in Japan. Excess use of nitrogen fertilizer has caused many problems such as strong acidification of soil, pollution of ground water and increase in Mechanical tea harvesting is now popular except for special type of tea. Over 98% of the tea fields in Japan are covered with clonal plants. The leading cultivar ‘Yabukita’ is grown in 74% of the total tea production area. With the growth of the Japanese economy after the mid-1950’s, many people living in agricultural areas moved to urban areas and mechanical harvesting was introduced to overcome the labor shortage problem. Clonal cultivars were also introduced to make the tea shoot lengths and budding times uniform and to prevent degradation of tea quality. The daily wage for tea pluckers is about $100.

Genetic diversity of oolong tea (Camellia sinensis) germplasms based on the nanofluidic array of single-nucleotide polymorphism (SNP) markers

As one of the most popular Chinese tea products, oolong tea involves the most complicated manufacturing process and the most abundant tea germplasm resources. However, the unclear genetic backgrounds of oolong tea germplasms have been biological limitations for tea breeding and quality control. In this study, high-throughput SNP technology was used to analyze the genetic diversity of 100 oolong tea landraces and cultivars. Ninety-six pairs of primers were selected and validated from the expressed sequence tag (EST) database of Camellia sinensis. The results verified 75 SNP loci that are able to accurately and efficiently determine the genetic relationships among Chinese oolong tea germplasms. The DNA fingerprints of 4 main oolong tea-producing areas were constructed by tracing the information of each site of the SNP. The Guangdong oolong tea germplasms were a relatively distinct group, while the genotypes of Taiwan oolong tea were similar to those of populations in Fujian. The tea germplasms in Southern and Northern Fujian had the largest intersections, and they also showed their own characteristics. Our results provide guidance for the identification, integration, and selection of parents for tea plant germplasms. Moreover, our study provides an effective tool to protect the diversity of tea germplasms and to assist in future breeding work.

Plant-Climate Interaction Effects: Changes in the Relative Distribution and Concentration of the Volatile Tea Leaf Metabolome in 2014-2016.

Climatic conditions affect the chemical composition of edible crops, which can impact flavor, nutrition and overall consumer preferences. To understand these effects, we sampled tea (Camellia sinensis (L.) Kuntze) grown in different environmental conditions. Using a target/nontarget data analysis approach, we detected 564 metabolites from tea grown at two elevations in spring and summer over 3 years in two major tea-producing areas of China. Principal component analysis and partial least squares-discriminant analysis show seasonal, elevational, and yearly differences in tea from Yunnan and Fujian provinces. Independent of location, higher concentrations of compounds with aromas characteristic of farmers’ perceptions of high-quality tea were found in spring and high elevation teas. Yunnan teas were distinct from Fujian teas, but the effects of elevation and season were different for the two locations. Elevation was the largest source of metabolite variation in Yunnan yet had no effect in Fujian. In contrast seasonal differences were strong in both locations. Importantly, the year-to-year variation in chemistry at both locations emphasizes the importance of doing multi-year studies, and further highlights the challenge farmers face when trying to produce teas with specific flavor/health (metabolite) profiles.

Transcriptomic Analysis Reveals Insect Hormone Biosynthesis Pathway Involved in Desynchronized Development Phenomenon in Hybridized Sibling Species of Tea Geometrids (Ectropis grisescens and Ectropis obliqua).

Ectropis grisescens and Ectropis obliqua are sibling species of tea-chewing pests. An investigation of the distribution of tea geometrids was implemented for enhancing controlling efficiency. E. grisescens is distributed across a wider range of tea-producing areas than Ectropis obliqua in China with sympatric distribution found in some areas. In order to explore reproductive isolation mechanisms in co-occurrence areas, hybridization experiments were carried out. Results showed they can mate but produce infertile hybrids. During experiments, the desynchronized development phenomenon was found in the hybridized generation of sibling tea geometrids. Furthermore, transcriptome analysis of those individuals of fast-growing and slow-growing morphs revealed that the insect hormone biosynthesis pathway was enriched in two unsynchronized development groups of hybrid offspring. More importantly, some genes regulating the synthesis of moulting hormone showed significantly up-regulated expression in fast-growing groups. Above all, metabolism of the juvenile hormone and synthesis of the ecdysone pathway were found to be crucially involved in the desynchronized development phenomenon. This research finding contributes to a better understanding of the mechanisms of insect development and reproductive isolation of two sibling species.

Soil Water Infiltration Model for Sprinkler Irrigation Control Strategy: A Case for Tea Plantation in Yangtze River Region

The sprinkler irrigation method is widely applied in tea farms in the Yangtze River region, China, which is the most famous tea production area. Knowledge of the optimal irrigation time for the sprinkler irrigation system is vital for making the soil moisture range consistent with the root boundary to attain higher yield and water use efficiency. In this study, we investigated the characteristics of soil water infiltration and redistribution under the irrigation water applications rates of 4 mm/h, 6 mm/h, and 8 mm/h, and the slope gradients of 0°, 5°, and 15°. A new soil water infiltration model was established based on water application rate and slope gradient. Infiltration experimental results showed that soil water infiltration rate increased with the application rate when the slope gradient remained constant. Meanwhile, it decreased with the increase in slope gradient at a constant water application rate. In the process of water redistribution, the increment of volumetric water content (VWC) increased at a depth of 10 cm as the water application rate increased, which affected the ultimate infiltration depth. When the slope gradient was constant, a lower water application rate extended the irrigation time, but increased the ultimate infiltration depth. At a constant water application rate, the infiltration depth increased with the increase in slope gradient. As the results showed in the infiltration model validation experiments, the infiltration depths measured were 38.8 cm and 41.1 cm. The relative errors between measured infiltration depth and expected value were 3.1% and 2.7%, respectively, which met the requirement of the soil moisture range consistent with the root boundary. Therefore, this model could be used to determine the optimal irrigation time for developing a sprinkler irrigation control strategy for tea fields in the Yangtze River region.

Switch to Sustainable Organic Tea Cultivation in the Eastern Black Sea Region of Turkey

Organic tea production is an arising issue in the last one decade in Turkey. The biggest actor in the tea sector CAYKUR initiated organic tea farming specially in Rize since 2007. But in all tea production areas in Turkey, namely the villages Rize, Trabzon, Artvin, Giresun and Ordu there are initial work about possible switch to organic tea farming. The biggest advantages of these villages are that chemicals are not applied against pests and diseases. With the switch from chemical fertilizers to organic fertilizers the way to organic tea farming can be initiated. Only a few research about the use of organic fertilizers in this tea plantation areas were initiated. In this study the changeover to sustainable organic tea production in Turkish tea plantations will be discussed. Keywords: tea, organic agriculture, sustainable agriculture DOI: 10.7176/JSTR/5-9-06