Agriculture, Ecosystems and Environment 168 (2013) 1–6 Contents lists available at SciVerse ScienceDirect Agriculture, Ecosystems and Environment jo ur n al homepage: www.elsevier.com/lo cate/agee Short communication Slash-and-burn agriculture: Establishing scenarios of runoff and soil loss for a five-year cycle Edivaldo Lopes Thomaz ∗ Department of Geography, Universidade Estadual do Centro-Oeste–UNICENTRO, St. Simeão Camargo Varela de Sá, 03–Mail Box, 3010, Postal Code 85.040-430 – Guarapuava, PR, Brazil a r t i c l e i n f o Article history: Received 4 August 2012 Received in revised form 10 December 2012 Accepted 22 January 2013 Available online 21 March 2013 Keywords: Shifting cultivation Fire Steep land Shallow soil Soil erosion a b s t r a c t Shifting cultivation is an age-old agricultural system that coexists with modern agricultural systems, particularly in the tropics. The characteristics and effects of shifting cultivation are well documented in the literature, including: soil degradation and erosion, nutrient depletion, impacts on biodiversity, and economic trends. Although studies report soil loss during the cropping period under shifting cultivation, few studies have assessed soil erosion during a full slash-and-burn cycle. The objectives of this study were to characterize runoff and soil loss for a full 5-year regeneration cycle in a slash-and-burn system. The measurement of runoff and soil loss was based on three replicate 2-m 2 plots installed in each monitored area. Three agricultural plots in different stages of regeneration were monitored. The data were analyzed by month and year for the 5-year regeneration cycle. Runoff and soil loss decreased exponentially from the burned phase to the early stage of secondary forest. Runoff and soil loss exhibited patterns similar to those of a forested area after only 4–5 years of regeneration. In general, areas undergoing slash and burn in the Guarapuava region are stable and the fallow length, as well. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The history of land occupation in the middle of South Parana is strongly related to the exploitation of natural resources. Today, agriculture is an important economic activity in the Guarapuava- Parana-Brazil region, and is characterized by two main types of systems. The first is modern commercial agriculture that uses advanced technologies in soybean, corn, oat, and barley production. The second is subsistence agriculture, which produces primar- ily corn and beans, and occupies less productive soils located on steep slopes that border escarpments and well-dissected valleys (Thomaz, 2009). Despite the emergence of modern agricultural systems (e.g., no till), the slash-and-burn system persists in many parts of the world, particularly in the tropics (Grau and Diego Brown, 2000; Borggaard et al., 2003; Mertz et al., 2009; Thomaz, 2009; Ziegler et al., 2009; Grogan et al., 2012; van Vliet et al., 2012). Many researchers believe that the slash-and-burn system would not be sustainable in the long term if the duration of the fallow period were to be reduced (Devendra and Thomas, 2002; Borggaard et al., 2003; Styger et al., 2007). Reducing the length of the fallow period has several conse- quences for areas that have been slashed and burned, including ∗ Corresponding author. Tel.: +55 42 3629 8117; fax: +55 42 3621 1090. E-mail address: edivaldo.thomaz@pq.cnpq.br increased soil degradation and erosion, a decrease in aggregate stability, and depletion of soil nutrients (Ziegler et al., 2009). Soil degradation takes place because insufficient time is allowed for vegetation and soil structure to develop and for stocks of carbon and nutrients to be replenished. As a consequence of yield reduc- tion, more areas are incorporated into agricultural production to maintain the required harvest levels. Land rotations take place within the boundaries of private prop- erty, because there is no vacant collective land. The farmers are the owners, and plan the rotation system to ensure cultivable land is available each year. The land rotation lasts from 3 to 5 years. Slashing is performed mainly in the winter (June, July, and August) and burning is conducted in early spring (September and October). Slashed vegetation is spread over the ground, and 1–2 months are needed to dry the vegetation prior to burning (Thomaz, 2009). A rotation cycle occurs over a period of varying intervals (3–5 years, 8–10 years, or >10–15 years). After slash and burn, vegetation is cropped for 1–2 years (Borggaard et al., 2003; Denich et al., 2005; Styger et al., 2007). The rotation cycle practiced in the Guarapuava region occurs over a 3- to 5-year interval, and is characterized by different land-use phases. The phases of a full cycle of land use, in order, are as follows: clearing, burning, growing, abandonment, and recovery (Thomaz, 2009). Several studies have reported soil loss during the cropping period but describe negligible or reduced soil loss during the fal- low period (Ziegler et al., 2009). In the Guarapuava region, the time 0167-8809/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.agee.2013.01.008