Sabirin and Hamdan

North Sumatra is a province in the Indonesian archipelago. Its tropical rain forest has a rich natural biodiversity to which traditional swidden agriculture has contributed a rich agro-biodiversity. However, this richness is steadily being replaced by the monocultures of oil palm and subsidary crops such as cacao, rubber, tea, tobacco and sugar cane on the large governmental plantations (3,359,719 ha.), private estates (498,988 ha.) and smallholder properties (770,408 ha.). On a considerable part of the total land area (7,168,068 ha) the rich biodiversity is being constantly eroded.

Impact of monocultures

Natural vegetation is generally cut and burned to clear the land for plantation crops. This means that biomass and biodiversity of considerable economic value is lost and soil degradation, erosion, and air pollution becomes a problem. Monocultures require considerable amounts of chemical fertiliser and pesticides that also pollute the environment, and the large amounts of water needed for oil palm have created water scarcities. As moncultures destabilise the agroecological system many oil palm pests and diseases have emerged, including Ganoderma sp, fire-caterpillar and termite. The cacao moth has become a particularly serious pest in cacao plantations and is very difficult to eliminate. Monocultures have had a deep impact on social relations and culture as well. Traditional community spirit like gotong royong (a system of mutual cooperation or community self-help) has been weakened and traditional products like King Banana, Sirih (Piper betle) and economic activities like animal husbandry are disappearing. The products of monocultures cannot be used directly for home consumption or home industries. Older farmers find it hard to remain in the production system and the system itself cannot be adapted to the conditions and needs of the local people.

Development of polycultures

The Pesticide Action Network North Sumatra (PAN-NS) began to develop alternative agricultural models to counter the problems caused by monocultures.  In this way they sought to generate higher levels of biodiversity and systems that were more environmentally friendly and delivered more economic benefit and profit. Since 1990, PAN-NS has been working with local farmers in different parts of North Sumatra to analyse and experiment with polycultures. Several polyculture models have been developed in which cacao (Theobroma cacao) plays an important role. Local trees like durian (Durio Zybetinus), duku (Lansium domesticum), petai papan (Parkia spiosa) or coconut (Cocos nucifera) are intercropped with cacao and pinang (Areca pinata) planted around the polyculture. In some places cattle can also be integrated into the system. Currently, PAN-NS is experimenting with local coffee as a main commodity crop.

The choice of trees to be interplanted will depend on whether the area is forest or cacao plantation. Banana (3×3 m.) can be planted as a pioneer crop on land where there are no trees. Local trees of economic significance can be planted in between the banana plants at spacing appropriate for the species concerned. In the second and third year banana plants will be replaced by cacao.

Sustainability analysis

The performance of a one hectare based polyculture model planted 10 years ago with 6 head of cattle integrated into the system has been compared to one hectare monoculture models of cacao and oil palm. Table 1 and 2 provide the economic data.

Table 1. Economic evaluation of the polyculture model

Table 2. Economic evaluation of a comparative monoculture (oil palm/cacao) model

Based on these data and the ecological, social and cultural arguments mentioned above, it can be concluded that monoculture models are not as profitable as they seem and are ecologically and socially unsustainable. Although this is increasingly being admitted, it has not yet resulted in alternative development policies and practices. Sustainability has to be taken seriously in agricultural research and policy making in Indonesia.

Conclusion

Based on our experiences we conclude that small-scale polyculture is a very appropriate model for rural people, particularly in regions with high biodiversity. Polyculture is affordable, it does not need much capital for external inputs and only requires 2-4 hectares of land for each household. Although animal theft can be a serious problem, polyculture is a model for profitable, environmentally friendly and sustainable development. In addition, it is feasible for farmers and NGOs to adapt the cacao based polyculture model to other tree crops like coffee if they are able to get the support of a funding agency through a revolving fund.

Sabirin and Hamdan, PAN North Sumatra, Jalan Rahmadsyah Gang Baik No. 476-C Medan, 20215 Indonesia,  Tel/Fax + 62- 61- 7366438, panns@indosat.net.id