Influence Of Greenhouse Cultivation On Tea Quality And Economic Benefits

Greenhouse cultivation of tea tree is a popular and new model for tea cultivation in recent years, it could help tea tree avoid frost and protect tea shoot from injury of late spring cold. And greenhouse cultivation could promote tea picking in advance, definitely increase economic benefits markedly.This research targeted spring green tea cultivating in greenhouse, and the tea cultivating out of greenhouse as CK. In order to analyze the influence of greenhouse on tea quality, the content of the main biochemical components and aroma components was determined, and sensory tasting was carried out. Furthermore, the background value of microclimate in greenhouse was observed. The observation and statistical analysis of the date of picking, budding density, indexes of hundred-buds weight and fresh leaf yield were carried out, to study the influence of greenhouse on the economic benefits. This research lay a theoretical foundation is for application and extension of facility cultivation. The results are summarized as follows:1, The analysis results of observation on the background value of microclimate in tea garden during three months of January to March in 2007 showed that greenhouse cultivation can improve the microclimate of tea garden. The daily mean temperature in greenhouse in sun days was increased by 5.9℃, and an increase of 1.8℃in cloudy or rainy days has been observed, furthermore, the diumal temperature in greenhouse is higher than CK; The daily mean relative humidity in greenhouse changed in range of 75-90% in different weather conditions, an increase of 16.20% in sun days and 13.21% in overcast days on daily mean relative humidity in greenhouse, comparing CK; The average light intensity on tea bush in greenhouse was decreased by 31.12%; and greenhouse cultivation can improve soil temperature at different layers.2, The biochemical analysis indicated that the content of amino acid and Water Extracts of green tea cultivating in greenhouse increased by 8.72% and 6%, respectively. The content of tea polyphenols and caffeine of tea cultivating in greenhouse decreased by 4.90% and 6.50%, respectively. The ratio of polyphenols to amino acid and content of fiber in tea cultivating in greenhouse decreased by 12.52% and 10.98%. The content of EGCG in tea cultivating in greenhouse was 2.01% higher than that of CK, and the contents of all other catechines are lower than CK. The total amount of five kinds of catechines in tea cultivating in greenhouse decreased by 9.96%, but catechin quality index of tea cultivating in greenhouse was higher than CK. The variation of these biochemical components in tea cultivating in greenhouse could improve the concentration and fresh taste of tea infusion, decrease the bitter and astringent taste.3, The result of aroma analysis by GC-MS indicated that about 57 differently aromatic compounds are isolated and identified from the two kinds of tea, among which 51 are found in tea in greenhouse and 43 in CK respectively. the basic aromatic components in two kinds of tea were similar on the whole, while striking divergences were found in the aromatic types, ratio of aromatic types, flavour index, total aromatic content and relative contents of the most of aromatic components. Compare the two kinds of tea, The flavour index and total aromatic contents in CK are 3 times and 1.38 times than tea cultivating in greenhouse; more components of low boiling point were found in tea cultivating in greenhouse, but more aromatic compounds and terpenoid components were detected in it.4, The results of sensory tasting showed that the quality of tea cultivating in greenhouse was higher than CK.5, The statistical analysis showed that the budding density and hundred-buds weight of tea in greenhouse increased by 10.08% and 28.37%, corresponding fresh leaf yield increased by 17.94%, And there was also an increase of 13.16% for wet-dry conversion rate in tea in greenhouse. Calculation the income of tea cultivating in greenhouse in term of the price of local tea market revealed that the output value per mu tea garden in greenhouse increased by 169.87%, deduct the cost of construction and maintenance of greenhouse, the net increase of the output value per mu was about 88.01%.In a Conclusion, the microclimate of greenhouse cultivation could improve tea quality, and cultivating in greenhouse could enhance the economic benefits in some extent, and greenhouse was worth to be extended in north tea garden.