ICECRD NEWS – With a narrow land area, the average rubber farmer in Indonesia is only able to pocket an income of around Rp. 3.2 million/year. Intercropping can help increase farmers’ income. However, in mature rubber plantations, the light intensity decreases so that the growth of intercrops is less than optimal. Researchers from Balittri revealed, changing the spacing to 2 mx 7 m can help increase light intensity without reducing the population significantly.
Around 80% of rubber plantations in Indonesia are dominated by smallholder plantations with narrow land ownership and low productivity. Worse, the consumption of natural rubber in the world tends to decline because they have to compete with the increasing use of synthetic rubber.
The decline in the world’s consumption of natural rubber also contributed to the decline in rubber prices. Farmers who have an average land area of around 0.7 ha/household are only able to pocket an income of around Rp. 3.2 million/year.
To increase income, farmers can plant intercropping in areas of land that are still vacant. However, intercrops are only optimally planted in the midst of young rubber. The reason is, in mature rubber (5-20 years) with conventional planting distances of 3 mx 6 m or 3 mx 7 m, the light intensity decreases by 40-60%.
In their research, Yulius Ferry and Saefudin from Balittri (2020) revealed that changing the spacing to 2 mx 10 m can increase light intensity up to 60-90% without reducing the plant population significantly.
With a spacing of 2 mx 10 m, a population of 500 plants/ha was obtained, the same as the spacing of 3 mx 7 m. The population decreased slightly when compared to a spacing of 3 mx 6 m which could be planted with 550 plants/ha. However, in terms of productivity, there was no decrease because plants experienced an increase in production per individual due to the sufficiency of CO2 more evenly.
There are various types of intercrops that can be planted. In young rubber, almost all food crops and secondary crops such as corn, peanuts, green beans can be planted. Meanwhile, in mature rubber, coffee and cacao cultivation which requires shade plants is very potential. Especially considering that the availability of coffee and cocoa is still not sufficient for domestic needs.
With a distance of 2 mx 3 m, there are about 594 cacao sticks that can be planted between the rubber. This population is equivalent to monoculture planting of cocoa in an area of 0.54 ha with a potential production of 1.5 kg/stem or 891 kg/ha/year of dry cocoa beans. If dry cocoa beans are valued at Rp. 23 thousand/kg, the potential income that farmers can get is Rp. 20.5 million/year. It is much bigger with the income that is only obtained from rubber.
Existing rubber plants that have been planted with a distance of 3 mx 7 m can still be spaced to increase light intensity and optimize intercropping. The trick is to cut down one tree alternately in 1 row of rubber plants 7 m apart. So, there is an empty area of 6 mx 14 m that can be planted with cocoa at a distance of 2 mx 3 m.
With this cropping pattern, the rubber population was 343 plants and cacao 2,880 plants. Even in existing plantations with irregular spacing, thinning can be done by felling rubber plantations with a strip system.
To support the spacing revolution and increase farmers’ income, government assistance is needed. Among other things, by providing intercropped plant seeds and forming a task force to help control pests and diseases which are coordinated by the local Agriculture Service. (Anjas)