Rubber based Agroforestry Systems (RAS) as Alternatives for Rubber Monoculture System

Smallholder rubber plantations in Indonesia, representing more than 80% of the total rubber areas, are very unique in the world. Most smallholder rubber areas are multi-strata in nature. Rubber is not the only perennial crop in that area, but also mixed with timber trees (forest re-growth), fruit trees, and different annual crops. Scientists identified these multistrata systems or called "Jungle Rubber" have multiple functions such as main income source for many farmers; keeping certain level of the forest biodiversity; Carbon sequestration; soil and water conservation. Many efforts have been done by the Indonesian Government to improve the productivity of jungle rubber through monocuture system such as Nucleolus Estate for Smallholding (NES); Project Management Unit (PMU); and Partial System. However, the rate of rubber replanting through those specific projects are too small compared to the total rubber areas in Indonesia. Taking into account the positive aspects of the Rubber Based Agroforestry Systems (RAS), ICRAF, CIRAD and IRRI worked jointly to implement various RAS systems in order to provide farmers better technological options for managing their farms. Results presented in this paper are collected from both on-station and on-farm research. At on-station, rubber planted at a double rows spacing (6m x 2m x 14m) with and without perennial intercrops was monitored and compared to that of the normal spacing (6mx3m). Rubber girth with double row spacing reached tappable size at five years after planting and similar to that planted with normal spacing. Rubber growth at the plot planted with Acacia mangium a very fast growing tree, at the same time with rubber, was very slow: a haft of that of the other treatments. If the fast growing trees are planted two years after rubber planting, then rubber growth is similar to that of normal spacing. Three types of RAS were tested at farmers' plots (RAS1, RAS2, and RAS3). The total number of participants is about 150 farmers, in 100 ha plots, distributed in Jambi, West Kalimantan, West Sumatra and South Sumatra. Results of clone comparison in RAS 1 type of trial (maintenance only on rubber rows) showed that rubber growth variability was more due to the variability of farmers' plots and frequencies of weeding. Rubber clones such as PB 260; RRIC 100 and BPM1 planted under RAS 1 can adapt the RAS conditions and can be tapped at 5-7 years after planting. These findings provide farmers alternatives to develop more environmentally friendly and divers systems in their farms, compared to that of monoculture system. This paper presents also various results related to more intensive RAS (RAS1 and RAS 3).