Monday, 7 January 2013

The diffusion of unsuccessful innovations: the myth of raised field agriculture
Pre-Columbian raised field agriculture is an extremely interesting topic that we have discussed in this blog before, here, here and here. We call raised fields “any prepared land involving the transfer and elevation of soil above the natural surface of the earth in order to improve cultivating conditions” (Denevan and Turner, 1974). Raised fields have received a lot of attention in studies related to pre-Columbian demography. They have been considered key in allowing dense populations of complex societies to inhabit seasonally flooded regions of South America in pre-Columbian times. Beyond their academic interest, raised field agriculture has also become popular among rural development workers and aid agencies working with small farmers in South America. For more than 30 years now, some archaeologists and NGOs have favoured the “re-introduction” of this pre-Columbian agricultural technique among modern day farmers. In their view, raised fields (which are considered analogous to the Chinampa system in Mexico) represent a promising pro-poor agricultural innovation which is more productive and sustainable than traditional agriculture (which, in the neo tropics is, basically, slash and burn).
A few days ago, Philippe C. Baveye published on-line a thorough debunk of such proposals  (Baveye in press) . It is a comment to a paper by Renard et al (Renard et al., 2012) where the authors advocate for the adoption of raised fields agriculture among modern farmers. The main points that Baveye puts forwards are: 1) There is no evidence that raised fields have supported dense populations in the past; 2) the pre-Columbian Chinampa system is unique. Therefore, it cannot be assumed that the productivity of the South-American raised fields, which are very different from the Mexican Chinampas, was comparable to that of the Chinampas; and 3) the purpose of raised fields was limited to water management:  soil drainage and/or irrigation. We reach very similar conclusions in (Lombardo et al., 2011). It is important to highlight that none of the projects designed to reintroduce raised field agriculture among small farmers in Bolivia and Peru have ever worked (actually, I am not aware of any successful rehabilitation anywhere in the Americas). Local farmers have no idea or knowledge about this ancient practice: this kind of indigenous knowledge was lost hundreds of years ago when the Spaniards got to America. Therefore, besides the technical problems described above, another reason behind this large scale failure is that raised field agriculture has been entirely “invented” by archaeologists and NGOs: the latest example I know of raised field rehabilitation project failures comes from an Oxfam project in the Beni - Bolivian Lowlands. The picture below shows the current state of the raised fields built by Oxfam in 2009, amid an important media coverage and support (for example, see this BBC article).

In 2011 raised fields were also built in the northern Beni.You see the state of the fields during the summer 2012 (photo below).

Hopefully, Baveye’s comment will contribute to make researchers more cautious before proposing the ‘reintroduction’ of raised field agriculture in rural communities.

Baveye, Philippe C. (2013). Comment on “Ecological engineers ahead of their time: The functioning of pre-Columbian raised-field agriculture and its potential contributions to sustainability today” by Dephine Renard et al Ecological Engineering

Denevan, W. M., and Turner, B. L., 1974, Forms, functions and associations of raised fields in the old world tropics: Journal of tropical geography, v. 39, p. 24-33.

Lombardo, U., Canal-Beeby, E., Fehr, S., & Veit, H. (2011). Raised fields in the Bolivian Amazonia: a prehistoric green revolution or a flood risk mitigation strategy? Journal of Archaeological Science, 38 (3), 502-512 DOI: 10.1016/j.jas.2010.09.022

Renard, D., Iriarte, J., Birk, J., Rostain, S., Glaser, B., & McKey, D. (2012). Ecological engineers ahead of their time: The functioning of pre-Columbian raised-field agriculture and its potential contributions to sustainability today Ecological Engineering, 45, 30-44 DOI: 10.1016/j.ecoleng.2011.03.007