West Sumatra field exercise

Secondary data review

Dr Edi Soenarjo (Director, SARIF) and Dr Iswandi Basri (Farming Systems Agronomist, SARIF) gave overview presentations on shifting cultivation in West Sumatra and specific information relating to the Sitiung transmigration area, the site of the field exercise. Shifting cultivation in West Sumatra mainly occurs in areas of secondary forest vegetation in the hilly or mountainous parts of the province (which cover about 50% of the area). There are currently 26 000 shifting-cultivator households farming 31 000 ha of land. The shifting cultivation cycle starts with farmers opening up one hectare of secondary forest during the late rainy season. Trees are felled manually and brush is left on the ground and burned during the late dry season. When the rains begin, food crops are planted and cash perennials are planted as intercrops (e.g. rubber). After 2-3 years the farmers open up a new secondary forest area for food crops, abandoning the previous site to alang-alang, or continue managing the perennial crops with infrequent weeding and gap filling.

There are several reasons why farmers pursue this particular farming system. These include the suitability of the systems to the infertile soils, lack of investment capital for more intensive systems, poor market and input supply, lack of skills or experience with alternative systems and lack of extension. The Government of Indonesia has pursued several strategies to manage shifting cultivation based on resettlement (transmigration, nucleus plantations and village improvement) and non-resettlement (improved farming systems, assistance in opening new rice fields and introduction of industrial crops). Table 3 illustrates the differences between the four types of shifting cultivation practices in West Sumatra.

Soil erosion is hypothesized to be lowest in type 1 and highest in type 4 shifting cultivation systems. In type 4 industrial crops expansion is the driving force for opening up new lands. Box 8 summarizes background information for the Sitiung area. (See map for location.)