RESPONSE OF LOW FREQUENCY HARVESTING SYSTEMS OF RUBBER UNDER DRIER CLIMATIC CONDITIONS IN SRI LANKA

Abstract

Escalating cost of production (COP) and inadequate supply of skilled harvesters are among the major issuesthat natural rubber industry face today. Low frequency harvesting (LFH) systems of which trees are tappedin a lesser frequency than once in two days, are considered to be one of the solutions to overcome theseissues. With the focus given to expand rubber in drier climates, the present study was aimed to investigateon the yield response of LFH systems, viz. harvesting trees once in three (d3), four (d4) and six (d6) days inthe intermediate zone (IZ) with the stimulation protocols developed for the wet zone (WZ). With thedecrease in harvesting frequency in IZ, yield per tree per tapping (GTT) increased, however yield per treeper year (YPT) decreased. No such declines were observed in WZ. Stimulation had no negative impact onpercentage dry rubber content in latex (%DRC) or incidence of Tapping Panel Dryness. Whilst only the S/2d3 system is acceptable for IZ in the present form, stimulation protocols are to be revised in other LFHsystems. Bark consumption was reduced significantly by LFH resulting in several long-term beneficialeffects. Effect of stimulation on latex physiology is also discussed.Keywords: Climate change, Ethephon, Hevea, Low frequency harvesting, Rubber