Different Latex Harvesting Systems and Their Impact on Bark Consumption and Economic Lifespan of Rubber Plantations in Sri Lanka

Abstract

Due to higher bark shavings and excessive recovery tappings (RT), the crop losses and the percentage tapping panel dryness (TPD) of rubber plantations are very high resulting in either uprooting before full economic lifespan or maintaining at uneconomical levels. Therefore, this study was carried out to determine the impact of different bark consumption (BC) rates associated with additional days of latex harvesting on yield and related parameters of rubber plantation including a preliminary survey in four estates (A, B, C and D). Also, on station experiment with five different harvesting systems i.e. T1 (S/2 d2 + rain guards (RG), T2 (S/2 d2 + 3 RT per month), T3 (S/2 d2 + 5 RT per month), T4 (S/2 d3 + 2.5% Ethephone +RG) T5 (S/2 dl), were tested with four rubber clones using split plot design in 3 replicates in 5.0 hectare field. Results showed that the estates A and B were managed poorly and their BC was at an alarming rate compared with C and D. In the on station experiment, the BC rate was significantly higher in T3 and T5 whilst significantly lowest in T4. Based on the prediction of tapping on two renewed panels, T3and T5will be finished within 7-9 years whilst T1 and T2 will be finished satisfactorily within 10-12 years. Both renewed panels of T4 will be utilized for more than 13 years due to low frequency of harvesting and significantly extended the economic lifespan of rubber. Finally, the higher rates of RT and daily tapping shorten the economic lifespan of the rubber plantations whilst not increasing significant yield per tree per tapping.