Improving smallholder farming systems in Imperata areas of Southeast Asia: alternatives to shifting cultivation

This monograph reports the results of the research project 'Improving smallholder farming systems in Imperata areas of Southeast Asia: a bioeconomic modelling approach' which was a formal collaborative effort between the Centre for Resource and Environmental Studies of Australian National University (CRES, ANU), Canberra, Australia, the SEAMEO Regional Center for Graduate Study and Research in Agriculture (SEARCA) in Laguna, Philippines, and the Centre for Agro-Socioeconomic Research (CASER), Bogor, Indonesia, with substantial funding from the Australian Centre for International Agricultural Research (ACIAR) and the Center for International Forestry Research (CIFOR). Many of the results reported here have already been published separately as 30 project papers (Imperata Project Paper - Improving Smallholder Farming Systems in Imperata Areas of Southeast Asia); 23 of these papers are included in this volume and together form its 21 chapters (22 papers, 2 as 1 chapter) and the appendix (1 paper). After an introduction (chapter 1), which outlines the nature of the Imperata (I. cylindrica var. major) problem and the methodology used, the monograph is arranged in 5 sections containing the other 20 chapters. Section 1, Modelling shifting cultivation (chapters 2-4), contains a bioeconomic analysis of traditional smallholder shifting cultivation farming systems where the fallow is Imperata. Section 2, Spontaneous tree growing by smallholders (chapters 5-8), contains a series of case study descriptions of successful (multipurpose) tree growing by smallholders on Imperata grasslands. The core of the modelling work is reported in Section 3, Modelling tree-based and other hedgerow farming systems (chapters 9-14) and Section 4, Incorporating livestock (chapters 15-17). These 2 sections contain chapters in which various tree-based interventions (growing trees in fallows, as hedgerows (in alley cropping), and in other intercropping systems) are modelled with and without an animal component; the tree species used are multipurpose trees and rubber, and work with natural vegetation strips and napier grass hedgerows is also described. Some of these modelled farming systems are already in place in farmers' fields, and in these cases, possible management policy or policy interventions analysed with the models can point the way to productive and economic improvements. In other cases, the farming systems modelled are experimental in nature. Imperata grows on uplands of various slopes, but some special attention is given to Imperata on steeply sloping land where soil erosion is a particular problem. The final Section 5, Fire management and carbon sequestration (chapters 18-21), addresses these 2 key issues in relation to tree growing on Imperata grassland, from the viewpoints of the individual smallholder and broader society. Abbreviated descriptions of the models used (SCUAF, Soil Changes Under Agroforestry; and BEAM, the rubber agroforestry model developed by the BEAM (Bio-Economic Agroforestry Modelling) Project based at the School of Agriculture of the University of Wales, UK, and composed of RRYIELD and RRECON) are given in the Appendix. Both these models underwent considerable change as the project proceeded, and so the BEAM analyses presented in this report, which were conducted using the final (November 1997) version of the model may be at variance with the results presented in the Imperata Project Papers produced earlier in the project.