ABSTRACT
Traditional shifting cultivation, sometimes called slash-and-burn agriculture, is only sustainable if it involves long periods of fallow. Under pressure from population growth, the fallow periods of tradition are being shortened, year by year, and the fallow lengths now prevailing in most of the uplands of Southeast Asia mean that shifting cultivation is no longer sustainable in either economic or environmental terms (Menz and Grist 1996). Therefore, policymakers and research organizations are encouraging smallholders to adopt alternative forms of agriculture that are more sustainable.
