Source Year: 2014

Rubber latex is collected by periodic excision of a thin shaving of the bark of Hevea tree. In addition to the volume, its value is determined by the dry rubber content (DRC) of latex. Dry rubber content of latex varies usually in the range of 20-45;and depends on several factors such as clone, season, climate and weather condition, stimulation programme, tapping system, soil condition etc. Hydrometry (using the Metrolac) is the most widely used method in the determination of DRC in the Sri Lankan rubber industry. Metrolac measurements are highly vulnerable to temperature of the latex/water mixture. Existing ready-reconer for Metrolac readings is valid only at 29 degree C, hence the present study was aimed at developing a Metrolac ready-reconer chart corrected for temperature variation in latex. Under natural and adjusted conditions, the new ready-reconer chart showed an accuracy level of 84;on average in the estimation of dry rubber content whilst the average accuracy by the existing chart was below 50;. The Metrolac estimated DRC differed in the range of -12.69;to 9.25;from the actual under existing ready reckoner whilst that was limited to -7.56;to 5.31;with the use of new ready-reckoner chart.