Tapping Regime
Table of Contents
a. Upward Tapping Cut (S/2)
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For Group I and Group II plantations, the upward tapping cut has a length equal to half the circumference of the trunk on either virgin or regenerated bark — denoted as S/2.
b. Downward Tapping Cut (Controlled Inversion)
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For a 20-year tapping cycle:
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From year 10–17: use a downward cut of S/4 or S/2, depending on trunk girth (>55 cm at 1.3 m above ground), ensuring a minimum cut length of 10 cm.
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From year 18 onward: use a downward cut of S/2.
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For a 17-year tapping cycle:
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From year 10–13: S/4.
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From year 14 onward: S/2.
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For Group III plantations, downward cut length equals half the trunk circumference, denoted as S/2U.
c. Tapping Frequency
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Standard tapping rhythm: every 3 days (d3), applied across all regions and clones.
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Alternative low-frequency tapping: where labor shortages occur, apply d4, d5, d6, or d7 (tapping every 4–7 days).
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Priority for transition to lower tapping frequencies:
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Newly opened plantations.
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Plantations recently shifted to BO-2 panels.
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Plantations starting downward tapping.
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Regions with distinct climatic conditions may increase tapping frequency temporarily, provided annual bark consumption remains within d3 limits.
Latex Stimulation Regimes
a. Clones with Moderate Response to Ethephon
Includes clones PB 235, PB 260, RRIV 106, RRIV 124, RRIV 114, RRIV 115, RRIV 209, IRCA 130, RRIV 2, RRIV 3, RRIV 4, RRIV 5, and others.
Stimulation Schedule Example (Simplified Summary):
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Concentration: ET 2.5% – 5%.
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Frequency: 2–10 times/year, depending on tapping rhythm (d3, d4, d5, d6).
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PB 260 and RRIV 124: reduce frequency by 1 application per year versus other clones.
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If rhythm is d5 or d6, increase stimulation frequency by 1–3 times/year relative to d4.
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Group III plantations: may use 2.5% ethephon with up to 1.5× stimulation frequency of 5% solutions.
b. Clones with High Response to Ethephon
Includes GT 1, RRIM 600, PB 255, RRIV 1, RRIC 121, VM 515, IAN 873, etc.
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Concentration: ET 2.5–5%, applied 4–12 times/year depending on clone and tapping rhythm.
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Group III plantations follow the same concentration rule as above.
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For final-tapping plantations, stimulation frequency and method are adjusted based on actual field conditions.
Physiological Diagnosis of Latex (Article 102)
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When abnormal yield trends are detected, latex physiological diagnosis is carried out to determine the appropriate tapping and stimulation regime.
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This process is conducted by the Vietnam Rubber Research Institute (VRRI).
Tapping Panel Planning (Article 103)
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Tapping panel (cutting area) layout must be planned from the first tapping year and maintained consistently throughout the tapping season.
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Design requirements:
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Upward and downward cuts are made on opposite sides of the trunk.
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If on the same side, the two cuts must be at least 30 cm apart.
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After shifting from BO-1 to BO-2 panels, no basal cuts are allowed in the first 3 months of the tapping season.
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Existing plantations with layouts differing from this standard must be reviewed and approved by the VRRI and the Group.