RUBBER NEWS

Technical Requirements for Latex Harvesting in Rubber Plantations

Posted on by content02.vinahugo
13
Oct

Tapping Season

  • The opening of tapping depends on regional climatic conditions — start when new foliage stabilizes and weather is favorable.

  • For dual tapping systems (upward + downward):

    • Downward cut starts at the beginning of the season.

    • Upward cut opens in mid-May or mid-September.

  • Pause tapping when trees start new leaf sprouting (“bird-foot stage”) — stop the entire block when 30% of trees show leaf sprouting, or earlier if latex yield becomes uneconomical.

  • Resume tapping when foliage is stable; in drought conditions, the opening date may be delayed.

  • Suspend tapping when the average temperature stays below 15°C for three consecutive days, and resume when it rises above 15°C.

Tapping Depth

  • The tapping depth must maintain 1.1–1.3 mm above the cambium layer for both upward and downward cuts.

  • Avoid:

    • Shallow tapping: >1.3 mm above cambium.

    • Deep tapping: <1.1 mm (risk of injury).

    • Cambium cut (cạo phạm): direct damage to the wood layer.

Bark Consumption and Wear Control

  • Upward tapping (miệng cạo ngửa):

    • d3: 1.1–1.5 mm/cut → max 18 cm/year.

    • d4: 1.2–1.6 mm/cut → max 15 cm/year.

    • d5–d6: 1.5–2.0 mm/cut → max 14 cm (d5), 12 cm (d6).

  • Downward tapping (miệng cạo úp):

    • Controlled height:

      • d3: ≤2.0 mm/cut, ≤3 cm/month.

      • d4: ≤2.2 mm/cut, ≤2.5 cm/month.

    • Beyond manual reach:

      • d3: ≤3.0 mm/cut, ≤4.5 cm/month.

      • d4: ≤3.5 mm/cut, ≤4.0 cm/month.

  • At the start of every tapping year, use templates (rập) to mark monthly and quarterly bark wear limits and maintain slope precision.

Tapping Line Standards

  • The tapping line must:

    • Follow the prescribed slope (32° or 45°).

    • Have a smooth latex groove, straight front and rear boundaries.

    • Be neat and level, not wavy, uneven, or exceeding boundary lines.

Pre- and Post-Tapping Operations

A. For Latex Collection (Liquid Method)

  • Before tapping:

    • Remove old latex crust, clean spout and cup, check hooks and alignment.

  • During tapping:

    • Direct latex into the cup before moving to the next tree.

    • Follow the tree sequence along the same row, alternating starting points each session.

  • After tapping:

    • Collect latex only after the supervisor’s signal.

    • Pour latex sequentially by tapping order; use a scraper to recover late drips.

    • For fast-coagulating clones, perform early collection and use ammonia stabilization as supplied by the factory.

    • For trees with stimulation treatments, latex is collected in the afternoon.

    • During rainy seasons, add coagulating chemicals provided by the factory to prevent overflow.

B. For Field-Coagulated Latex (Mủ Đông)

  • Before tapping: Remove old crust, check rain shields, ensure cups are clean and secured.

  • Replace or redistribute cups when full to avoid overflow.

  • After tapping: Collect latex every 1–3 tapping cycles, drain excess serum before delivery.

  • Apply colorant or coagulant for traceability and quality control.

Tapping, Collection, and Latex Quality

a. Tapping Hours

  • Begin when daylight is sufficient to see the cutting line clearly.

  • Do not tap during noon heat or when temperature is below 15°C.

b. Latex Collection Hours

  • Liquid latex:

    • Collect only after team leader’s order.

    • From tapping to delivery must not exceed 7 hours.

  • Coagulated latex:

    • Collect every 1–3 sessions; allow 1–2 hours draining before weighing.

    • Leave a small portion of serum in the cup.

c. Latex Receiving and Handling

  • Liquid latex:

    • Filter using a 5 mm sieve, cover containers to prevent contamination.

    • Label by worker name or ID for traceability.

  • Coagulated latex:

    • Sort, clean impurities (leaves, bark, soil, metal, fibers).

    • Weigh and record separately by tapping section.

    • During truck loading, filter through 3 mm mesh.

  • For large plantations (50–100 ha), establish central collection stations with resting shelters for workers.

d. Latex Quality Control

  • Check internal quality of coagulated latex and allow at least 1 hour drying before weighing.

  • Rinse “mủ dây” to remove sand and bark particles.

  • Latex must be free from contaminants and meet factory-specific processing standards.

  • For latex used in centrifuged rubber (latex concentrate):

    • Regularly monitor VFA (volatile fatty acid) levels; if VFA > 0.05, the factory must trace and disinfect all related collection tools and containers.

e. Collection Station Requirements

  • Must be clean, roofed, ventilated, with latex pits, water tanks, and drainage systems.

  • Include rest areas for tappers and storage for clean containers.

  • Keep weighing tools, DRC/TSC measuring devices dry and sanitized.

f. Latex Preservation and Transport

  • For SVR and RSS:

    • Preserve with ammonia (NH₃).

    • Maintain pH ≤ 8, prevent premature coagulation.

  • For Centrifuged Latex:

    • Use 10% NH₃ solution, dosage 0.3–0.4% by latex weight, split into:

      • 70% added daily to worker’s 35L collection bucket (before latex).

      • 30% added to transport tank (before loading).

  • For Coagulated Latex:

    • Avoid PP or PVC sheets/containers.

    • Store by batch and type, keeping areas clean, dry, and shaded.