CLIMATE-CHANGE AND ITS IMPACT ON THE PROPERTIES OF AGRICULTURAL SOILSIN THE ARGENTINEAN ROLLING PAMPAS

The agriculture of the Argentinean pampean region is undergoing a reco nversion process as a result of a more intensive use of agrotechnologi es. The ongoing changes are likely to overlap with the greenhouse warm ing-related climatic changes and atmospheric CO2 increase predicted fo r 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 P ampas, which support 10 to 15% of the national grain crop and oilseed production. Relation of wheat/soybean-maize crops in 45 agricultural s oils was simulated using the EPIC model (Erosion/Productivity Impact C alculator; US Dept of Agriculture), which was previously calibrated an d validated for local conditions, for the 1996 to 2050 period under 2 scenarios: (1) no climate change, and (2) climate change conditions de rived from regional climate parameters projected by the GISS general c irculation model combined with a CO2 concentration of 550 ppm. The 197 1 to 1995 period was simulated under neutral conditions with the purpo se of defining soil conditions for 1996. It was found that in the even t 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 er osion. In contrast, since it was assumed that the erosive storm patter n would remain unchanged, there would be no variations in the erosion rate. A general decrease in potential soil fertility of 6 to 10% for t otal organic N and 7 to 20% for organic C would take place after a 55 yr period. The sustainability of certain soils of the Carcarana River basin, particularly the Villa Eloisa series, would be at a higher risk .