Practices of six-day tapping system for enhanced natural rubber yield and quality in China

Four days tapping systems (d4) is dominant for latex harvesting in state farm of China.However, now, six days tapping system (d6) is being widely adopted because of its advantages in labor productivity and reduction in tapping workers. In this study, a comprehensive comparison of harvesting efficiency and rubber quality were conducted between d6 and d4 tapping system for 6 years to evaluate the feasibility of replacing d4 with d6 tapping system. The results showed that the average yield per tree per tapping of d6 was 51.9 % more than that of d4. A higher molecular weight, fewer non-rubber components (e.g., nitrogen), higher ash, and major-metal-ion (e.g., magnesium and calcium) contents of were found in rubber harvested using d6 system compared with d4 system. Furthermore, the Mooney viscosity (M v ) and initial plasticity values (P 0 ) of raw natural rubbers from two tapping system were significantly different ( P < 0.05). Also, the vulcanization characteristics including highest and lowest torque (MH and ML, respectively) and torque difference (M H − M L ) were highly significantly different ( P < 0.01). The average P 0 , M v , M H , and M H − M L of rubber from d6 were 12.61 %, 10.96 %, 9.75 % , and 10.27 % higher than those of d4, respectively. Consequently, the tensile strength, tear strength, hardness, and 500 % constant tensile stress of the vulcanized rubber from d6 were significantly higher compared with that from d4. Overall, this study demonstrated that the d6 tapping system could enhance the labor productivity and rubber quality. • Comprehensive comparison of harvesting efficiency and rubber quality were conducted between d6 and d4 tapping system for 6 years. • NR Quality evaluation includes properties of fresh latex, raw rubber, and vulcanized rubber. • The d6 tapping system enhance the labor productivity and rubber quality compared with d4 system.