|Agricultural Expansion and Pioneer Settlements in the Humid Tropics (UNU, 1988, 305 pages)|
|10. Resource use of frontiers and pioneer settlement in southern Sumatra|
One of Indonesia's biggest national problems is its extremely uneven population distribution. On the one hand there is the over-populated central island group of JavaMadura-Bali, with around 700 people/km2; on the other, there are the huge frontier lands of the scarcely populated outer islands, with an average of some 30 people/km2. It is no wonder that this pronounced demographic imbalance seeks a solution. Apart from the well-known Transmigrasi programme of the Indonesian government, which has grown in the past decade to be the largest voluntary settlement scheme in the world (Hardjono 1977; Arndt 1983), there has emerged almost unnoticed by the public, an even larger flow of spontaneous pioneer settlers, who are estimated to outnumber the state directed migrants by several times.
Among the different outer islands of Indonesia, Sumatra (474,000 km2 and about 30 million inhabitants) has become the most favoured frontier region of both planned and spontaneous settlers. The island is not only located near Java but is also, in economic terms, the richest and most active of the outer islands (oil, natural gas, timber, tin, estates), and it has sufficient land reserves (fig. 1). For these reasons, Sumatra has become known among Indonesians as "pulau harapan" ("island of hope"). The island's southern provinces (Lampung, South Sumatra, Bengkulu, and Jambi) in particular, due to their proximity to Java, have become the major target region. Between 1969 and 1982, the area received more than 1 million people, or 60 per cent of all official transmigrants. In addition, an unknown number of spontaneous migrants are steadily trickling into the region.
Local authorities in Lampung, the southernmost province, estimate the figure to be about 100,000 persons each year for their province alone.
How do all these new settlers achieve their livelihood in their new habitat?
Although it is true that Sumatra contains extensive land reserves (not even 20 per cent of the total area is settled and agriculturally used), it is also a fact that the agricultural potential is gradually being reduced because, quite understandably, the most favourable places have long been occupied by local inhabitants. Such places include the volcanic areas within the mountain zone and the fertile levees along the big rivers in the eastern lowlands. Any pioneer settler who wants to clear a piece of land has to be content with land which the indigenous people were either unwilling or unable to cultivate, or which has been abandoned due to its inferior quality.
According to an FAO-UNDP study (1973), only about 10 per cent of Sumatra's soils can be classified as "good" or "fairly good" for agricultural purposes, whereas 90 per cent are qualified as "moderate," "fairly poor," or "poor" (fig. 1). The main reason for the poor soil quality of large tracts of Sumatra lies in the fact that the entire island belongs to the humid tropics where, through steady leaching by excessive rain and rapid decomposition of the organic material, the soils tend to become impoverished much faster than in the other climatic zones of the world.
On the other hand, the abundant and rather evenly distributed supply of solar energy and water ensures the possibility of a year-round production of a variety of crops. And even the poor soil quality has, to a considerable degree, been successfully compensated for by the introduction of improved farm technologies, with the result that formerly rather worthless regions can now be turned into productive farm land and provide new opportunities for pioneer settlers.
The most crucial issue remains with the selection of appropriate agricultural production systems which are suitable for these critical zones. The age-old experience of local farmers and recent experiments in agricultural research lead to the conclusion that the cultivation of perennial bush and tree crops is probably the most suitable production system for the fragile ecosystem of the humid tropics. Satisfactory, albeit not optimal, results can be expected from cultivation on inundated fields, particularly if these are used for wet-rice cropping. Rather unfavourable conditions generally prevail for annual dry-land crops, especially if one tries to grow them permanently in the same field. In general, the only way to grow such crops successfully is to apply shifting cultivation techniques with slash-and-burn clearing (swidden farming). Most types of cattle husbandry also show only limited returns under humid tropical conditions (Ruthenberg 1971).
Such general statements on the suitability of humid tropical regions for agricultural purposes have to be modified according to the topography of a particular area. In the frontier regions of Sumatra the following three major types of ecosystem can be distinguished, each exhibiting certain constraints but also offering specific opportunities for pioneer settlement: (1) the mountain zone, (2) the peneplains, and (3) the swampy lowlands.