Effects of Lung Pruning and Pruning Cycle Period on Selected Mineral Concentrations in Clonal Tea Leaves
P. Okinda Owuor
*
Department of Chemistry, Maseno University, P.O. Box 333 40105, Maseno, Kenya.
Gladys Onsando
Kenya Agricultural and Livestock Research Organization, Tea Research Institute, P.O. Box 820 20200, Kericho, Kenya.
Simon O. Ochanda
Kenya Agricultural and Livestock Research Organization, Tea Research Institute, P.O. Box 820 20200, Kericho, Kenya.
Jennifer A. Odak
Department of Chemistry, Maseno University, P.O. Box 333 40105, Maseno, Kenya.
Bowa O. Kwach
Department of Chemistry, Maseno University, P.O. Box 333 40105, Maseno, Kenya.
David K. Kowanga
Department of Chemistry, Maseno University, P.O. Box 333 40105, Maseno, Kenya.
Humprey O. Agan
Department of Chemistry, Maseno University, P.O. Box 333 40105, Maseno, Kenya.
*Author to whom correspondence should be addressed.
Abstract
Aims: Pruning in tea management reduces plucking heights to manageable levels, rejuvenates the plant and helps in removing diseased/dead branches. However, it leads to loss of crop and black quality decline in the pruning year. Despite the recorded benefits and challenges, influence of pruning on mineral composition of pluckable shoots is not documented. Although in rim-lung pruning the tippings produced lower quality tea compared to the lung leaves, the differences in their mineral composition has not been determined.
Study Design: First trial used split plot design and second trial was set up as factorial two in a randomized complete block design.
Methodology: The study determined the changes in levels of Al, Ca, K, Mg, Mn, Na and P in clonal black tea due to variations in the length of pruning cycle and compared their composition in clonal black tea from lung and tipping leaves in rim-lung pruning using ICPEA.
Results: The tipping leaves had higher (p 0.05) K, Mg and P but lower Al, Ca, Mn and Na than the lung leaves, demonstrating that in a single plant nutrient are partitioned differently in tipping and lung leaves. The mineral composition of pluckable shoots in lungs is different from that in tippings in the same plant. The levels of K, Mg, and P declined (p 0.05), while levels of Al, Ca, Mn and Na increased (p 0.05) as the period from previous pruning increased, demonstrating the nutrients composition in pluckable tea leaves vary with time in a pruning cycle. The variations in the nutrients due to pruning cycle length and rim-lung pruning were different in the tea clones (p 0.05), demonstrating that tea clones partition the nutrients differently. These variations could be due to differences in growth rates in tipping and lung leaf, as the length of pruning cycle increased. In most cases, the extent of the variations changed with clones causing clones*pruning interactions (p 0.05) effects.
Conclusion: These results demonstrate that in tea leaf analysis advisory systems, the set norms should vary with pruning operations and clones.
Keywords: Leaf minerals, tea clones, pruning, tea leaf, nutrients