Tea garden

About: Tea garden is a research topic. Over the lifetime, 1369 publications have been published within this topic receiving 5757 citations.

Lead contamination in tea garden soils and factors affecting its bioavailability

Abstract: The consumption of heavy metals is detrimental to human health and most countries restrict the concentration of metals such as lead (Pb) in food and beverages. Recent tests have detected high Pb concentrations in certain commercial brands of tea leaves and this finding has raised concerns for both producers and consumers. To investigate what factors may be contributing to the increase in Pb accumulation in the tea leaves we collected tea leaves and soils from tea producing areas and analyzed them for Pb concentration, pH and organic matter content. The result showed the Pb concentration of 47% investigated tea leaves samples was beyond 2 mg kg(-1), the permissible levels given by China. The total Pb concentration in the surface and subsurface soil layers averaged 36.4 and 32.2 mg kg(-1), respectively which fall below of the 60 mg kg(-1) limit provided for organic tea gardens in China. The pH of the tea garden soils was severely acidic with the lowest pH of 3.37. Soils under older tea gardens tended to have a lower pH and a higher Pb bioavailability which was defined as the amount of lead extracted by CaCl2 solution than those under younger tea gardens. We found that the concentration of bioavailable Pb and the percentage of bioavailable Pb (bioavailable Pb relative to total Pb concentration) were positively correlated with soil H+ activity and soil organic matter content, and the organic matter accumulation contribute more effects on Pb bioavailability in these two factors. We conclude that soil acidification and organic matter accumulation could contribute to increasing Pb bioavailability in soil and that these could increase Pb uptake and accumulation in the tea leaves.

Classification of Black Tea Taste and Correlation With Tea Taster's Mark Using Voltammetric Electronic Tongue

Abstract: Tea quality assessment is a difficult task because of the presence of innumerable compounds and their diverse contribution to tea quality. As a result, instrumental evaluation of tea quality is not practiced in the industry, and tea samples are assessed by experienced tea tasters. There had been a very few reports where an electronic tongue has been used for the discrimination of taste of tea samples. In this paper, a voltammetric electronic tongue instrument is described, which can declare tea-taster-like scores for black tea. The electronic tongue is based on the principle of pulse voltammetry and consists of an array of five working electrodes along with a counter and a reference electrode. The five working electrodes are of gold, iridium, palladium, platinum, and rhodium. The voltage equivalent of the output current from between the working electrode and the counterelectrode generated out of the tea liquor when excited with pulse voltage between the working electrode and the reference electrode has been considered for data analysis. First, the sampled data have been compressed using discrete wavelet transform (DWT) and are then processed using principal component analysis (PCA) and linear discriminant analysis (LDA) for visualization of underlying clusters. Finally, different pattern recognition models based on neural networks are investigated to carry out a correlation study with the tea tasters' score of five different grades of black tea samples obtained from a tea garden in India. The efficacy of the classifier has been established using tenfold cross-validation methods.

Soil Microbial Community Structure in Diverse Land Use Systems: A Comparative Study Using Biolog, DGGE, and PLFA Analyses

Abstract: Biolog, 16S rRNA gene denaturing gradient gel electrophoresis (DGGE), and phospholipid fatty acid (PLFA) analyses were used to assess soil microbial community characteristics in a chronosequence of tea garden systems (8-, 50-, and 90 year-old tea gardens), an adjacent wasteland, and a 90-year-old forest. Biolog analysis showed that the average well color development (AWCD) of all carbon sources and the functional diversity based on the Shannon index decreased (P forest > tea garden. For the DGGE analysis, the genetic diversity based on the Shannon index was significantly lower in the tea garden soils than in the wasteland. However, compared to the 90-year-old forest, the tea garden soils showed significantly higher genetic diversity. PLFA analysis showed that the ratio of Gram positive bacteria to Gram negative bacteria was significantly higher in the tea garden soils than in the wasteland, and the highest value was found in the 90-year-old forest. Both the fungal PLFA and the ratio of fungi to bacteria were significantly higher in the three tea garden soils than in the wasteland and forest, indicating that fungal PLFA was significantly affected by land-use change. Based on cluster analysis of the soil microbial community structure, all three analytical methods showed that land-use change had a greater effect on soil microbial community structure than tea garden age.

Tea planting affects soil acidification and nitrogen and phosphorus distribution in soil

Abstract: Land use change from natural forest to agricultural land often affects the properties of soil, resulting in various environmental problems. A field study was conducted to evaluate the effects of land use change from forest to tea cultivation on soil acidification as well as the nitrogen (N) and phosphorus (P) leaching risk. The soil acidification and nutrient concentrations in soil at a depth of 0–200 cm in two tea gardens with differing stand ages (10 and 100 years old), and three different fertilizer input levels (low-input, medium-input, and high-input), and in the forests adjacent to these tea gardens were measured at the Tea Research Institute of the Chinese Academy of Agricultural Sciences. Tea cultivation caused soil acidification throughout the 0–200 cm soil profile, and the lowest soil pH was observed in the 20–40 or 40–60 cm soil depth. Both nitrate (NO3−) and ammonia (NH4+) concentrations increased as the tea stand age and fertilizer input levels increased at the 0–90 cm soil depth. Compared to the forests, significantly higher concentrations of NO3− and NH4+ were observed in the 90–200 cm soil of the tea gardens, suggestive of a high risk of N leaching loss in the tea gardens. Longer tea cultivation times and higher input levels also increased the concentration of soil available P and CaCl2-P at 0–90 cm soil depth, and a change point was observed in the relationship between soil available P and CaCl2-P. Depending on the relationship between soil available P and soil CaCl2-P, the soil CaCl2-P concentration dramatically increased when soil available P surpassed 75.1 mg kg−1. This study also indicated that soil acidification could occur in deep soil profiles as a result of tea cultivation and excessive fertilization; thus, there is a high risk of N and P leaching loss in tea gardens.

Organophilic cultivation method for tea

Abstract: The invention relates to a method for cultivating tea, particularly the method for organically cultivating tea, which comprises the following processes: (I) establishing an artificial complex ecological organic tea garden; (II) selecting tea seeds of the organic tea garden; (III) planting tea; (IV) seedling stage management; (V) soil management of the organic tea garden; (VI) nutrient management and utilization of the organic tea garden; (VII) pest control of the organic tea garden; (VIII) tea pruning of organic tea. The method for cultivating tea has the following positive effects that: as the organic tea is the inevitable trend of future tea production, the invention regulates organic planting of tea in China and promotes the large-scale development of tea producing areas toward harmlessness and organification; the method for cultivating tea does not rely on advantage factors of microecological nature of producing areas, makes full use of modern technical achievements and has strong technical operability, thereby ensuring the quality of the organic tea.