Pre-Columbian agriculture in the Bolivian Lowlands: Construction history and management of raised fields in Bermeo

River logjams cause frequent large-scale forest die-off events in southwestern Amazonia

“…On the other hand, the presence of Cuberene paleochannels in the very same area as the pre-Columbian earthworks suggests that, prior to the construction of the raised fields, logjams were less frequent or happened further to the east than their modern location. Raised fields were built to mitigate the risk posed by extreme floods (Lombardo et al, 2011) and their geometry, size, and location responded to the local hydrology (Rodrigues et al, 2015(Rodrigues et al, , 2016. The fact that raised fields in the Cuberene area were built along the whole slope that goes from the former levees of the Cuberene River to the former backswamps ( Fig.…”

An insight into pre-Columbian raised fields: the case of San Borja, Bolivian lowlands

“…Soils along the Río Maniqui are in general acidic, with a pH ranging from 3.86 to 5.11, but they are very heterogeneous in terms of plant available nutrients, mostly correlated to the particle size of the sediments (Guèze et al, 2013). Soils in the southern LM are generally loam or silty loam and silty clay loam (Boixadera et al, 2003); all soils are subject to hydromorphic processes and are mainly acidic (Boixadera et al, 2003;Rodrigues et al, 2015), with some exceptions of saline soils (pH of > 8) and soils with accumulation of calcium carbonates in the subsoil (Boixadera et al, 2003).…”

“…Up till now, habitational sites associated to raised fields have only been dated in four locations: the San Juan site (AD 446-613) and the Cerro site (AD 1300-1400), in the northern part of the LM (Walker, 2004), and the Moxitania site (AD 700-1000), Abularach and Carretera Santa Ana sites (AD 900-1100), close to San Ignacio de Moxos (Villalba et al, 2004). Raised fields in Bermeo, close to San Ignacio, have been dated; they were used intermittently from AD 570-770 up to the 14th century (Rodrigues et al, 2015). …”

“…Distributed over a wide range of latitudes, spanning from almost 20 • N to 40 • S, they exist in very different environmental contexts: in seasonal inundated floodplains, around lake shores and in coastal zones; all of them associated to permanent or semi-permanent high water levels (Erickson, 1988;Kolata and Ortloff, 1989;Wilson et al, 2002;Dillehay et al, 2007;Denevan, 2001;. Since their discovery about 100 years ago by Erland Nordenskiöld (Denevan, 2009), increasing interest in raised field agriculture has led to a body of literature focused on understanding how raised fields worked and were managed and how pre-Columbian societies were sustained (Gliessmann et al, 1985;Kolata and Ortloff, 1989;Erickson, 2008;Iriarte et al, 2010;McKey et al, 2010;Lombardo et al, 2011a;Renard L. Rodrigues et al: An insight into pre-Columbian raised fields: the case of San Borja, Bolivian lowlands et al., 2011;Whitney et al, 2014;Rodrigues et al, 2015;Walker, 2004). Nevertheless, there is still limited data and a lack of consensus about the time frame during which raised fields were in use, why they were built and how they were managed.…”

“…Very little is known with regards to the environmental characteristics of the areas where raised fields were built in lowland South America. Only recently some studies have started to include detailed soil studies providing an insight to the internal structure of raised fields and their relation to the environment Lombardo et al, 2011a;McMichael et al, 2014;Rodrigues et al, 2015).…”