IMPERATA MANAGEMENT STRATEGIES USED IN SMALLHOLDER RUBBER-BASED FARMING SYSTEMS

A large proportion of global natural rubber production takes place in Southeast Asia. The majority of this rubber is produced by smallholder s. Thailand, Indonesia and Malaysia are the three principal countries involved. In Malaysia and Indonesia the smallholder sector accounts fo r 72% and 84% of total rubber production respectively. In other countr ies rubber plays a significant role on a more local basis. Imperata is a serious problem for the smallholder rubber farmer in most of Southe ast Asia in three respects: the high cost (labour and/or capital) of o pening Imperata-infested land, its competitive effect on rubber and an nual intercrops, and the fire hazard that it poses during the dry seas on as a major source of combustible material. The costs of Imperata to smallholders are substantial in terms of a direct loss through fire a nd revenue foregone or delayed as a result of competition. Most smallh olders intercrop their rubber during the first 1-3 years after plantin g it, and during this period Imperata is reasonably well controlled. I ntercropping is only feasible for a limited period because of limited soil fertility and/or the shading effect of the rubber trees, After in tercropping, Imperata tends to establish itself for a few years until it too is shaded out by the rubber. This is the problem period, during which farmers practise only limited weed management, if any. A large amount of research has been done on methods of controlling Imperata, b ut the recommended methods have been generally spurned by smallholders unless they have been given subsidies to apply them. This paper descr ibes the precise nature of the Imperata problem, with reference to som e of the smallholder rubber-based farming systems within Southeast Asi a; the different Imperata control strategies currently practised in th ese farming systems; and some of the constraints on the adoption of cu rrently and recently recommended practices. It then proposes a ten-poi nt agenda for research on Imperata control, including two ways in whic h current research programmes could be usefully reoriented: first, the y need to take greater account of smallholder farming systems and cons traints; and second they should shift their emphasis from single-metho d to integrated control systems.