ABSTRACT
Natural rubber constitutes 46% of the total rubber materials produced in 2016. It is produced from the latex of Para’ rubber tree (Hevea brasiliensis Muell. Arg.), which is native to the Amazon basin of South America. Today, the center of natural rubber production is in Southeast Asia, where 75% of the world’s natural rubber was produced by Thailand, Indonesia, Malaysia, India, and Vietnam in 2015. The demand for natural rubber has consistently lagged behind production. To increase production, rubber plantations in Asia have extended into areas that are suboptimal for the growth of rubber and difficult to manage sustainably. Weed management is the greatest challenge in the maintenance of young rubber. The majority of troublesome weeds infesting rubber plantations are invasive perennial species, which are very difficult to control. The most notorious of these is cogongrass [Imperata cylindrica (L.) P. Beauv.]. The best strategy for long-term weed management in rubber is by establishing a suitable cover crop between rubber rows supplemented with slashing and herbicide application around the base of rubber. This prevents invasive perennials from getting established and minimizes soil erosion. The majority of rubber farmers are smallholders and for them, rubber agroforestry (intercropping food crops with young rubber) is necessary. Some intercrops (i.e. tea, banana) have been shown to increase the water use efficiency, growth, and yield of rubber. The rubber agroforestry ecosystem is more resilient against environmental fluctuations than monoculture rubber and it also supports a higher level of biodiversity. However, converting natural forests into rubber plantations destroys the habitat of endemic species and impacts the biodiversity of flora and fauna negatively. Establishing rubber plantations on hilly lands also increases soil erosion, limits the practice of agroforestry, and decreases water quality. Resource limitations and lack of knowledge and support systems are among the factors that prevent rubber farmers from adopting best management practices for the crop and for sustainable weed management.
