9. Food, coffee and casuarina: an agroforestry system from the Papua New Guinea highlands.

In: Agroforestry Systems in the Tropics; Kluwer Academic Publ., Dordrecht, The Netherlands; 1989, pp. 269-275

The paper describes an agroforestry farming system from the Papua New Guinea highlands (1,400-2,100 m) that has been developed by village farmers since about 1960 and has expanded rapidly since about 1970.

The majority of new coffee plantings made by smallholders in recent years have been in agroforestry systems that incorporate annual and perennial food crops, coffee and shade species. One such system is described here.

Major components of the system are numerous species of annual and perennial food crops (especially bananas), Arabica coffee and Casuarina oligodon. This system provides food, a cash crop and timber for construction and fuel.

C. oligodon is a fast-growing woody species that provides shade and timber for fencing, house construction and firewood. Its timber is easy to split and it burns well. The food crops include bananas (Musa cvs) (mostly triploid cultivars at these altitudes), taro (Colocasia esculenta and Xanthosoma sagittifolium), sugarcane (Saccharum officinarum), maize (Zea mays), highland "pitpit" (Setaria palmifolia), Amaranthus spp., Oenanthe javanica, Rungia klossii and others. Other components which may be present are nut pandanus (Pandanus jiulianettii) at altitudes above 1,800 m and oil pandanus (Pandanus conoideus) below 1,700 m. Pigs commonly graze under established coffee/casuarina/banana stands, but they are not a critical component of the system. Cassava (Manihot esculenta) is an important component of a similar system used on better drained soils, but not in this system on the wetter soils.

The basic structure of the system is that mixed vegetable gardens are gradually converted into coffee/banana gardens and eventually into coffee/casuarina stands.

The system described here is an extension of the traditional mixed vegetable garden system and it is the most widely practised of the recently developed integrated food/coffee/timber systems.

The overall performance of the system has not been quantified and hence not evaluated. Judging by the system's rapid expansion and widespread adoption, it is much more efficient than the officially promoted method of establishing coffee.

Because the canopy is maintained continuously by a sequence of faster and slower growing species, the need for weeding is minimized.

It is a conservation system in that the soil is protected from the direct action of the elements by continuous vegetative cover.

A reasonable level of managerial ability is needed to manage the system, but this is within the capability of most village growers. The level of management may be more difficult to attain when larger plantings are being established in a limited time, for example areas larger than 3 ha.

The research needs for this system are numerous and urgent, given that this farming system and similar ones are the most important ones that are used to establish new plantings.

Once farmer practices have been documented, innovations and potentially superior techniques need to be evaluated in controlled experiments. The growth pattern, nitrogen-fixing ability and ecological requirements of

Casuarina also require immediate study.

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Agroforestry

Africa, Benin, Nigeria, Zaire, humid tropics, ICRAF, case studies, traditional farming systems

KANG, B.T. et al.