Boletim do Museu Paraense Emílio Goeldi. Ciências Humanas ISSN: 1981-8122 [email protected] Museu Paraense Emílio Goeldi Brasil Antunes Ribeiro Filho, Alexandre; Adams, Cristina; Sereni Murrieta, Rui Sergio The impacts of shifting cultivation on tropical forest soil: a review Boletim do Museu Paraense Emílio Goeldi. Ciências Humanas, vol. 8, núm. 3, septiembre -diciembre, 2013, pp. 693-727 Museu Paraense Emílio Goeldi Belém, Brasil Available in: http://www.redalyc.org/articulo.oa?id=394035001013 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Bol. Mus. Para. Emílio Goeldi. Cienc. Hum., Belém, v. 8, n. 3, p. 693-727, set.-dez. 2013 The impacts of shifting cultivation on tropical forest soil: a review Impactos da agricultura itinerante sobre o solo em florestas tropicais: uma revisão Alexandre Antunes Ribeiro Filho I, Cristina Adams I, Rui Sergio Sereni Murrieta I IUniversidade de São Paulo. São Paulo, São Paulo, Brasil Abstract: 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. Keywords: Shifting agriculture. Shifting cultivation system. Swidden. Soil. Ecological impact. Sustainability. Resumo: A sustentabilidade da agricultura itinerante é, atualmente, um tema bastante debatido no meio científico e institucional, sobre o qual ainda não existe consenso. Como forma de subsidiar este debate, realizamos um levantamento da literatura pertinente, publicada nos últimos 30 anos, a respeito dos impactos da agricultura itinerante sobre os solos tropicais. Este levantamento demonstrou que a natureza dos impactos depende da fase do sistema (conversão, cultivo ou pousio) e das propriedades do solo (físicas, químicas e biológicas). Também foram sugeridos indicadores de qualidade do solo para essa prática agrícola em florestas tropicais, que poderão servir como base para o acompanhamento das tendências de conservação e degradação de solos impactados. Pesquisas futuras devem aprimorar as escolhas destes indicadores, baseando-se em critérios principalmente práticos, para que possam ser utilizados pelos agricultores itinerantes. Palavras-chave: Agricultura itinerante. Sistema agrícola itinerante. Derrubada-e-queima. Solo. Impacto ecológico. Sustentabilidade. RIBEIRO FILHO, Alexandre Antunes; ADAMS, Cristina; MURRIETA, Rui Sergio Sereni. The impacts of shifting cultivation on tropical forest soil: a review. Boletim do Museu Paraense Emílio Goeldi. Ciências Humanas , v. 8, n. 3, p. 693-727, set.-dez. 2013. Autor para correspondência: Alexandre Antunes Ribeiro Filho. Universidade de São Paulo. Programa de Ecologia, Instituto de Biociências. Rua do Matão, travessa 14, n. 321. Cidade Universitária. São Paulo, SP, Brasil. CEP 05508-090 ([email protected]). Recebido em 04/09/2012 Aprovado em 30/08/2013 693 The impacts of shifting cultivation on tropical forest soil: a review IN TR ODU CTI ON density has made this practice impossible in Europe Shifting cultivation systems (SCS) and their impacts on soil (Boserup, 1989; Worster, 2003). Estimates of how many and vegetation have been widely studied by many research people worldwide currently depend on shifting agriculture groups (Ju o and Manu, 1996; Palm et al. , 1996; Nandwa systems for their subsistence vary from 35 million to 1 billion and Bekunda, 1998; Giardina et al ., 2000; Lawrence and people (Lanly, 1982; Attiwill, 1994; Brady, 1996; Kleinman Foster, 2002; Bruun et al ., 2009; Mertz et al ., 2009). The et al ., 1996; IFAD et al ., 2001; Sanchez et al ., 2005). current intensification of studies on the topic is likely related The basic phases of SCS are the following: (1) to problems linked to global warming (Lal et al ., 1995; conversion, (2) cultivation, and (3) fallow (Kleinman et Kauffman et al. , 2009) and the deforestation of rainforests al ., 1995). Conversion includes the slash-and-burn of (Fearnside, 2005). This review article aims to identify and native vegetation. This practice physically exposes the classify the impacts of SCS on the properties of tropical soil for planting, eliminates competing plant cover, and forest soils. Moreover, based on our results, we suggest improves soil fertility by leaving it less acidic and with a soil quality indicators that may lead to new, more specific greater availability of nutrients (Kleinman et al ., 1995). quantitative indicators for SCS and may also contribute to The length of the cultivation period varies depending on the sustainable management of these systems. the region (one to three years), but is always shorter than In the methods section, we present the the fallow period. The fallow period may be natural or methodological procedures used for this review. In the managed and allows recovery from the soil degradation following section, we present and discuss the results resulting from conversion and cultivation. The duration of of the identification and classification of the types of the fallow period is variable, but it must be long enough SCS impacts on the physical, chemical, and biological for woody vegetation to become dominant (Eden and properties of the soil. In the fourth section, we suggest Andrade, 1987; Kleinman et al ., 1995; Mertz et al ., qualitative indicators (physical, chemical, and biological) 2009). The SCS leads to the formation of mosaics of for the evaluation of the impact of SCS on the soil and secondary forests in different stages of regeneration, of trends in soil degradation and conservation. Finally, in contained within a mature forest matrix that helps to the last section, we discuss our results and make some sustain them (Conklin, 1961; Harris, 1971; Hiraoka conclusions based on the sustainability of SCS. and Yamamoto, 1980; Egger, 1981; Altieri et al ., 1987; McGrath, 1987; Adams, 2000a; Martins, 2005). SHI FTI NG CUL TI VATI ON SYSTEMS AND The similarities among shifting cultivation practices FO RESTS in different tropical forests exist because farmers mimic Shifting cultivation (SC) is one of the main subsistence the characteristics and ecological processes of the forest activities of small-scale societies and rural populations system in their agricultural activities (Beckerman, 1983; in tropical forests. This system has been practiced for Altieri, 1989; Adams, 2000b; Warner, 2001). This forest thousands of years (Harris, 1971; Dove and Kammen, management system appears to maintain the genetic 1997; Altieri, 1999; Bellwood, 2005) and is based on the diversity of the crops and of the secondary forests in ecological processes of forest ecosystems (Boserup, 1965; regeneration and avoids soil degradation by minimizing Altieri, 1999; Long and Zhou, 2001; Vadez et al ., 2004; its exposure to erosive and drying elements. The period Pedroso-Junior et al ., 2008, 2009). Over the past three of disturbance is compensated by the recovery of the centuries, the practice of SC has been restricted to forested soil-vegetation system (McGrath, 1987; Kleinman et al ., areas of the tropics, because the increase in population 1995; Pedroso-Junior et al ., 2008, 2009). 694 Bol. Mus. Para. Emílio Goeldi. Cienc. Hum., Belém, v. 8, n. 3, p. 693-727, set.-dez. 2013 SCS appear to be sustainable under specific conditions the impact on soils could compromise forest biodiversity of low demographic densities and the use of low input (FAO, 1985; Myers, 1993; Bandy et al ., 1993; Brady, 1996). technologies (Kleinman et al ., 1995; Johnson et al ., 2001; Moreover, the areas used for shifting cultivation could Pedroso-Junior, 2008, 2009). However, the rapid and function as a significant cause of global warming (Fearnside, important climatic and economic-political transformations 2005), and the soil could be considered a source of CO 2 that have occurred in recent decades (Mertz, 2002; emissions into the atmosphere (Brown and Lugo, 1990), Pedroso-Junior et al ., 2008, 2009; Van Vliet et al ., 2012) which would not be compensated by secondary forest have produced a growing concern about the sustainability of growth during the fallow period. SCS (Bruun et al ., 2009) and the food security of subsistence These negative concerns regarding the environmental farmers (Altieri et al ., 1987; Adams et al ., 2005). sustainability of the SCS have guided public policies Historically, the debate on the sustainability of shifting in many tropical countries towards eradicating this cultivation has been associated with the conservation of agricultural system (Ziegler et al ., 2009). This system tropical forest ecosystems and characterized by antagonistic has