Climate change and its impact on the properties of agricultural soils in the Argentinean Rolling Pampas

Abstract

The agriculture of the Argentinean pampean region is undergoing a reconversion process as a result of a more intensive use of agrotechnologies. The ongoing changes are likely to overlap with the greenhouse warming-related climatic changes and atmospheric CO2 increase predicted for the next century. The goal of this study is to assess the potential impact of such changes on certain properties of soils of the Rolling Pampas, which support 10 to 15% of the national grain crop and oilseed production. Rotation of wheat/soybean-maize crops in 45 agricultural soils was simulated using the EPIC model (Erosion/Productivity Impact Calculator; US Dept of Agriculture), which was previously calibrated and validated for local conditions, for the 1996 to 2050 period under 2 scenarios: (1) no climate change, and (2) climate change conditions derived from regional climate parameters projected by the GISS general circulation model combined with a CO2 concentration of 550 ppm. The 1971 to 1995 period was simulated under neutral conditions with the purpose of defining soil conditions for 1996. It was found that in the event of a change in climate, physical properties would change to a lesser degree than chemical properties. The soil bulk density would decrease by 8% with respect to the baseline scenario in soils under risk of erosion. In contrast, since it was assumed that the erosive storm pattern would remain unchanged, there would be no variations in the erosion rate. A general decrease in potential soil fertility of 6 to 10% for total organic N and 7 to 20% for organic C would take place after a 55 yr period. The sustainability of certain soils of the Carcarañá River basin, particularly the Villa Eloisa series, would be at a higher risk.