ISHS Acta Horticulturae 1007: II All Africa Horticulture Congress
YIELD DECLINE IN VEGETATIVELY PROPAGATED TEA (CAMELLIA SINENSIS (L.) O. KUNTZE) UNDER CONTINUOUS MECHANICAL HARVESTING |
| Authors: | G.M. Madamombe, N.J. Taylor, E. Tesfamariam |
| Keywords: | harvesting methods, photoassimilate accumulation, photosynthetically active radiation |
| DOI: | 10.17660/ActaHortic.2013.1007.102 |
| Abstract:
Labour costs and shortages and cost of production has resulted in the tea industries in central and southern Africa becoming unprofitable. This has led to the full mechanization of shoot harvesting by using hand-held and ride-on machines. However, it is evident that yield has declined with mechanical harvesting. Under mechanical harvesting, due to its non-selective nature, a higher percentage of buds and immature shoots are harvested, which may impact overall bush photosynthesis, carbohydrate partitioning and radiation interception dynamics. Studies conducted at Tingamira estate, Chipinge, Zimbabwe during 2010/2011 showed significant differences in yield between hand plucking and machine harvesting treatments, with hand plucking producing higher yields than machine harvesting treatments (p<0.05). There were significant differences between hand plucking and mechanical harvesting in the fractional interception of photosynthetically active radiation (FI-PAR) at five and ten days after harvesting. The FI-PAR intercepted at 10 cm below the surface five days after plucking was 77, 48 and 66% decreasing to 10, 5 and 8%, 20 cm below surface for hand plucking, hand-held and ride-on machines respectively. Ten days after harvesting, at 20 cm below the surface the intercepted radiation was 15, 5 and 9% for hand plucking, hand-held and ride-on machines, respectively. The FI-PAR intercepted under hand plucking was much greater compared to other methods of harvesting. The thick maintenance foliage at 10 cm below the surface intercepts most of the radiation restricting the amount of FI-PAR intercepted at 20 cm leading to the significant reduction in the FI-PAR intercepted at this level at both 5 days and 10 days after plucking. | |
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