The geographic focus of the project is the Pampas of central-eastern Argentina. Hall et al. (1992) and Morello & Solbrig (1997) describe the region’s climate, soils, and cropping systems. We chose the Pampas because of its importance to Argentina’s economy (51% of exports, and 12% of GDP, 1999–2001; Díaz 2002) and because the region has marked interannual and inter-decadal climate signals (Ropelewski & Halpert 1987, 1989; Castañeda & Barros 1994; Vargas et al. 1999; Rusticucci & Penalba 2000). The similarity in production scale, crops grown and technology of the Pampas to those in other major production areas (the US Midwest, Brazil, Canada) with comparable climate signals (Parry 1985; Mauget & Upchurch 1999; Phillips et al. 1999) suggest a broader relevance of our results.

The climate of the Pampas is influenced by multiple factors. The South Pacific exerts year-round influence through the mid-latitudes storm track and the Pacific-South American teleconnection pattern. Other influences are the South Atlantic Convergence Zone, and SSTs in the SW Atlantic (Liebmann et al. 1999; Barros et al. 2000; Robertson & Mechoso 2000).

ENSO is the major single source of seasonal-to-interannual climate variability (Grimm et al. 2000; Montecinos et al. 2000). There are marked links between ENSO and precipitation in the Pampas in Nov-Dec, a critical period for important summer crops. In these months, El Niño events are associated with higher median precipitation and higher likelihood of positive (wet) rainfall anomalies than other ENSO phases, whereas La Niña events show markedly lower median rainfall and a narrower range of anomalies (Podestá et al. 1999; Rusticucci & Vargas 2002).

In addition to the interannual signal, the climate of the Pampas shows marked inter-decadal variability. A steady increase in annual precipitation (particularly in spring-summer) has been observed since the 1970s over most of central-eastern Argentina (Krepper at al 1989; Castañeda & Barros 1994; Rusticucci & Penalba 2000). Decadal precipitation signals are mimicked by streamflows of major rivers in the region (Paraná, Paraguay, Uruguay, and Negro) that show an increase most marked since about 1970 (García & Vargas 1998; Genta et al. 1998; Robertson & Mechoso 1998).

ENSO has impacts on agriculture in the Pampas (Messina et al. 1999; Jones et al. 2000; Podestá et al. 2002). El Niño (La Niña) events have a positive (negative) effect on maize yields. Soybean yields decrease during cold events, but the impact of warm events is less marked (Podestá et al. 1999).

In previous NSF work we linked climatic, agronomic, and financial models to characterize vulnerability to ENSO of current maize production systems in Argentina (Ferreyra et al. 2001). We combined synthetic weather conditioned on ENSO phase (Grondona et al. 2000), a maize simulation model (Ritchie et al. 1998) and stochastic prices in an enterprise budget to derive probability distributions of profits for each ENSO phase. Strong consistency between model and historical results suggests this approach can be used confidently in this project.

The goal of enhancing and sustaining the ability of decision-makers to use climate information can be accomplished most effectively through existing “boundary organizations” that perform information communication and translation (Guston et al. 2000; Agrawala et al. 2001; Cash et al. 2003). Our partner Asociación Argentina de Consorcios Regionales de Experimentación Agrícola (AACREA) is an example of a boundary organization. AACREA is a non-governmental, non-profit organization of farmers with a focus on dissemination of new technologies. Members join regional groups of 7–12 farmers assisted by a technical advisor. Each group meets monthly, a ready-made opportunity for researchers to interact with group members.

The Argentine Meteorological Service (Servicio Meteorológico Nacional, SMN) is a governmental organization charged with collecting, analyzing, and disseminating weather and climate information. SMN was identified by farmers as their primary source of climate information. SMN also can be viewed as a boundary organization, as it has a dual mandate for producing and communicating climate information.

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We have selected two locations in the Pampas: Pergamino (33º 56' S, 60º 33' W) and Pilar (31º 41' S, 63º 53' W), that respectively represent near-optimal and relatively marginal agricultural conditions. Pergamino is in the most productive subregion of the Pampas (Paruelo & Sala 1993). Cropping systems include maize, soybean, and a wheat-soybean doublecrop. In contrast, Pilar is in the northern, semi-arid end of the Pampas (Dardanelli et al. 1997). Characteristic rotations include maize and soybean. Contrasting climatic and ecological conditions between sites will let us explore differences in vulnerability to climate, risk perceptions, and scope for adaptive management.

Total rainfall and the annual precipitation cycle vary between locations (Prohaska 1976; González & Barros 1996). Median annual precipitation is 937 mm (738 mm) in Pergamino (Pilar). In Pilar, the annual rainfall cycle has a marked winter minimum that, together with limited soil water storage, makes summer crops very dependent on ENSO-influenced spring precipitation. The winter minimum in Pergamino is less marked.  Total October-March (spring-summer) median rainfall has varied significantly over time between the two sites, with Pergamino seeing a 12% increase between 1931-1950 and 1975-1994; Pilar increased by 33% between the same epochs.

Contrasting climatic and ecological conditions between the two sites let us explore differences in vulnerability to climate, risk perceptions, and the scope for adaptive management.

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