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Effects of Harvesting Policy and Nitrogen Application Rates on the Production of Tea in Central Africa. II. Quality and Total Value of the Crop

Published online by Cambridge University Press:  03 October 2008

J. B. Cloughley
J. B. Cloughley
Affiliation:
Tea Research Foundation of Central Africa, PO Box 51, Mulanje, Malawi
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Summary

The black teas produced from the field treatments described previously (Cloughley et al., 1983) were evaluated chemically and organoleptically. Increasing N application rates and harvesting larger shoots had adverse effects on the liquor quality as assessed by theaflavin (TF) analysis, and on the value of the product as assessed by tea tasters' sensory examination. There were also large, regular intraseasonal fluctuations in TF content, small values corresponding to occasions of crop peaks. Shoots predominantly of 2 or 3 leaves and a bud harvested from plots given 135 kg N ha−1 generated the largest total cash value. A total value index (TVI), involving yield and quality, is introduced and illustrated.

Type
Research Article
Information
Experimental Agriculture , Volume 19 , Issue 1 , January 1983 , pp. 47 - 54
Copyright
Copyright © Cambridge University Press 1983

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References

REFERENCES

Basu, R. P. (1978). Plucking in relation to quality of tea. Proceedings of UPASI Conference, Bulletin 35:62–66.Google Scholar
Bhatiah, I. S. & Ullah, M. R. (1962). Metabolism of polyphenols in the tea leaf. Nature 193:658–660.CrossRefGoogle Scholar
Cloughley, J. B. (1978). Malawi tea prices 1977–78. Tea Research Foundation of Central Africa, Annual Report 1977–78, 109–111.Google Scholar
Cloughley, J. B. (1979). The effects of N-application on chemical composition, yields, quality and total value of two clonal teas. Tea Research Foundation of Central Africa, Annual Report 1978–79, 117–126.Google Scholar
Cloughley, J. B. (1980). The effect of fermentation temperature on the quality parameters and price evaluation of Central African black teas. Journal of the Science of Food and Agriculture 31:911–919.CrossRefGoogle Scholar
Cloughley, J. B. (1981a). Storage deterioration in Central African tea: changes in chemical composition, sensory characteristics and price evaluation. Journal of the Science of Food and Agriculture 32:1213–1223.CrossRefGoogle Scholar
Cloughley, J. B. (1981b). Effects of some field variables on the dry-matter content of tea shoots. Journal of Agricultural Science, Cambridge 97:227–229.CrossRefGoogle Scholar
Cloughley, J. B. (1981c). A method to monitor theaflavin production during the fermentation of tea. LUSO: Journal of Science and Technology (Malawi) 2:53–56.Google Scholar
Cloughley, J. B. & Ellis, R. T. (1980). The effect of pH modification on the quality parameters of Central African black teas. Journal of the Science of Food and Agriculture 31:924–934.CrossRefGoogle Scholar
Cloughley, J. B., Ellis, R. T. & Harris, N. (1981). Black tea manufacture. 2. Comparison of the liquoring properties, particle size distribution and total value of teas produced by different processing systems. Annals of Applied Biology 99:367–374.CrossRefGoogle Scholar
Cloughley, J. B., Grice, W. J. & Ellis, R. T. (1983). Effects of harvesting policy and nitrogen application rates on the production of tea in Central Africa. I. Yield and crop distribution. Experimental Agriculture 19:33–46.CrossRefGoogle Scholar
Ellis, R. T. (1963). The effect of artificial manures on tea making quality. Tea Research Stations, Annual Report 1962–63, 27–30. Tea Association of Central Africa.Google Scholar
Ellis, R. T. & Cloughley, J. B. (1981). The importance of theaflavin in tea liquors. International Tea Journal 2:7–8.Google Scholar
Forrest, G. I. (1968). Studies in tea biochemistry and fermentation. Tea Research Foundation of Central Africa, Annual Report 1967–68, 65–78.Google Scholar
Forrest, G. I. & Bendall, D. S. (1969). The distribution of polyphenols in the tea plant. Biochemical Journal 113:741–755.CrossRefGoogle ScholarPubMed
Harris, N. & Ellis, R. T. (1981). Black tea manufacture. 1. Effects on leaf structure of different processing systems. Annals of Applied Biology 99:359–366.CrossRefGoogle Scholar
Hilton, P. J. (1974). Tea. In Encyclopedia of Industrial Chemical Analysis, 18, 455–516 (Eds Snell, F.D.Ettre, L. S.). New York: John Wiley.Google Scholar
Hilton, P. J. & Ellis, R. T. (1972). Estimation of the market value of Central African teas by theaflavin analysis. Journal of the Science of Food and Agriculture 23:227–232.CrossRefGoogle Scholar
Hilton, P. J. & Palmer-Jones, R. W. (1975). Chemical assessment of quality in tea and its relation to market value over an extended period. Journal of the Science of Food and Agriculture 26:1681–1687.CrossRefGoogle Scholar
Hilton, P. J., Palmer-Jones, R. W. & Ellis, R. T. (1973). Effects of season and nitrogen fertilizer upon the flavanol composition and tea making quality of fresh shoots of tea (Camellia sinensis L.) in Central Africa. Journal of the Science of Food and Agriculture 24:819–826.CrossRefGoogle Scholar
Palmer-Jones, R. W. & Hilton, P. J. (1976). Use of chemical assessment of quality in the economics of tea production in Malawi. Journal of the Science of Food and Agriculture 27:7–14.CrossRefGoogle Scholar
Roberts, E. A. H. (1962). The economic importance of flavanoid substances in tea fermentation. In The Chemistry of Flavanoid Compounds, 468–512 (Ed. Geissman, T.A.). Oxford: Pergamon Press.Google Scholar
Sanderson, G. W. (1964). Chemical composition of fresh tea flush as affected by clone and climate. Tea Quarterly (Ceylon) 35:101–110.Google Scholar
Sanderson, G. W., Berkowitz, J. E., Co, H. & Graham, H. N. (1972). Biochemistry of tea fermentation: products of the oxidation of tea flavanols in a model tea fermentation system. Journal of Food Science 37:399–404.CrossRefGoogle Scholar
Tea Brokers' Association (1978). Weekly Tea Market Reports, Tea Brokers' Association of London.Google Scholar
Tea Research Foundation of Central Africa (1969). Fertilizers for Tea in Central Africa.Google Scholar
Tea Research Foundation of Central Africa (1979). Fertilizers for Tea in Central and Southern Africa.Google Scholar
Willson, K. C. & Choudhury, R. (1968). Fertilizers and tea quality. Two and a Bud (India) 15:92–95.Google Scholar