The sustainability of shifting cultivation is presently a topic of debate in scientific and institutional communities; however, there is no current consensus. To address this debate, we performed a search of the pertinent literature that was published during the last 30 years on the impact of shifting agriculture on tropical soils. This search revealed that the nature of the impact depends on the shifting cultivation system (SCS) phase (conversion, cultivation, or fallow) and on the soil properties (physical, chemical, and biological). We also suggest soil quality indicators for evaluating this agricultural practice in tropical forests, which may be used as a basis for analyses on the tendencies of conservation and degradation of impacted soils. Future research should improve the choices of these indicators, relying mostly on practical criteria, so they can be used by shifting cultivators.

O sistema agrícola itinerante (SAI), uma das formas mais antigas de agricultura, ainda é praticado pelas comunidades quilombolas do Vale do Ribeira-SP, mesmo que venha sendo parcialmente substituído pela agricultura permanente e comercial em monocultivo de pupunheira para palmito. Este artigo teve como objetivo avaliar a produtividade entre os diferentes sistemas de cultivo, discutindo os motivos e impactos desta transição e sua sustentabilidade, assim como os impactos econômicos para as comunidades. Na metodologia foram utilizados: itinerário técnico, entrevistas semiestruturadas, visitas a campo e cálculo do valor agregado líquido. Com relação à rentabilidade dos diferentes sistemas (itinerante e permanente) a agricultura permanente se mostrou mais eficiente em termos de renda e no uso do trabalho, do que o SAI. Entretanto, o SAI desempenha um papel não só de produção de alimentos, mas também como parte de um complexo de relações socioambientais.

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Shifting cultivation systems (SCS) are currently restricted to tropical areas. The classical nutrient flow model for SCS considers increasing soil fertility from the conversion phase, with the addition of nutrients contained in the biomass that was slashed and burned, and made available through ash. This study assessed the impacts of the conversion and cultivation phases on soils subjected to an SCS practiced quilombola populations of the Atlantic Forest, Brazil. We used a diachronic method in six experimental plots divided into two fallow age classes (10-15 and 25-30 years). The results showed that fire does not have a primary role in the cycling and maintenance of the stock of nutrients in the soil/vegetation complex. Furthermore, the soil fertility status was not significantly altered during the conversion and cultivation phases. Thus, the quilombola SCS shows specificity and that soil fertilization does not necessarily occur during the conversion and cultivation phases of SCS. The soils from fallow areas between ten and 30 years have eutrophic fertility conditions in relation to the mature forests, and are therefore viable from an agronomic standpoint. Therefore, the data on the impact of the quilombola SCS on soils concur as proscribed by law.