EVALUATION OF SIMPLE HAND-HELD MECHANICAL SYSTEMS FOR HARVESTING TEA (CAMELLIA SINENSIS)

Abstract

Over an eight-year period, harvesting methods based on simple mechanical aids (blade and shear) were evaluated against hand harvesting on mature morphologically contrasting tea clones in Southern Tanzania. The effects of shear step height (5-32 mm) and the harvest interval (1.8-4.2 phyllochrons) were also examined. Except in the year following pruning, large annual yields (5.7-7.9 t dry tea ha −1 ) were obtained by hand harvesting at intervals of two phyllochrons. For clones K35 (large shoots) and T207 (small shoots), the mean harvested shoot weights were equivalent to three unfurled leaves and a terminal bud. The proportions of broken shoots (40-48 %) and coarse material (4-6 %) were both relatively high. Using a blade resulted in similar yields to hand harvesting from K35 but larger yields from T207 (+13 %). The yield increase from clone T207 was associated with the harvest of more shoots and heavier shoots, smaller increases in canopy height, and a higher proportion (7-9 %) of coarse material compared to hand harvesting. On bushes, which had been harvested by hand for two years following pruning, using flat shears (no step) supported on the tea canopy resulted, over a three year period, in yields 8-14 % less than those obtained by hand harvesting and, for clone K35, a reduction in the leaf area index to below 5. The development of a larger leaf area index is made possible by adding a step to the shear. However, since annual yields were reduced by 40-50 kg ha −1 per mm increase in step height, the step should be the minimum necessary to maintain long-term bush productivity. As mean shoot weights following shear harvesting were about 13 % below those obtained by hand harvesting, there is scope, when using shears, to extend the harvest interval from 2 to 2.5 phyllochrons.

PHYSIOLOGICAL BASIS OF YIELD VARIATION OF TEA (CAMELLIA SINENSIS) DURING DIFFERENT YEARS OF THE PRUNING CYCLE IN THE CENTRAL HIGHLANDS OF SRI LANKA

“…The pruning height may vary in different tea-growing regions of the world, depending on the required intensity of †Corresponding author: janendrad@yahoo.com pruning, as determined mainly by climatic conditions and recovery time, and the method of pruning (i.e. whether manual or by machine) as determined primarily by the availability of labour and cost-effectiveness (Anon., 1986;Burgess et al, 2006;Grice et al, 1984;Kandiah and Wimaladharama, 1980;Kaptich, 1985;Willson, 1992). Pruning involves the removal of a significant proportion of branches along with almost all the foliage.…”

Effect of Mechanical Harvesting on Yield and Quality of Tea in Tanzania

“…Madamombe et al (2015) obtained slightly lower yields with a hand-held machine than with a wheeled machine, but did not give table heights or harvest intensity figures. Burgess et al (2006) found that harvesting with shears gave lower yields than hand plucking at the same harvest interval. With shears or hand-held harvesting machines cutting height cannot be controlled with the precision that a wheeled machine allows, so damage to the next generation of shoots may be more likely to occur.…”

“…It seems that the very hard plucking has increased potential shoot number in treatment B, but at the same time may have damaged the canopy (low LAI) and thus reduced light interception and photosynthetic production. Burgess et al (2006) considered that an LAI of at least 4 was required to maintain yields, but mean LAI was only 3.5 for treatment B. The result is that source activity is no longer sufficient to support the growth of all shoots, and die-back starts to occur.…”

Identification of differentially expressed genes in dormant (banjhi) bud of tea (Camellia sinensis (L.) O. Kuntze) using subtractive hybridization approach

“…However, in harvested tea, apical dominance causes dormant shoots to be produced under favorable growth conditions, and the synchronized flushing cycle causes periods of active terminal bud and dormant terminal bud production [3]. So far, very few studies have been done to describe the dormancy due to the mechanical shearing in tea [20]. Thus, understanding the molecular mechanisms involved is critical for the manipulation of bud dormancy.…”