Abstract:

This paper studies the changes of groundwater, climate and land use in the Pampas of Argentina. These changes offer opportunities and threats. Lowering groundwater without irrigation causes drought and successive crop and yield damage. Rising groundwater may alleviate drought as capillary rise supports root water uptake and crop growth, thus narrowing the difference between potential and actual yields. However, rising groundwater may also limit soil water storage, cause flooding in metropolitan areas and have a negative impact on crop yields. Changing land use from continuous soy bean into crop rotations or natural vegetation may decrease groundwater recharge and thus decrease groundwater levels. In case of crop rotation however, leaching of nutrients like nitrate may increase. We quantified these impacts using integrated dynamic crop growth and soil hydrology modelling. The models were tested at field scale using a local dataset from Argentina. We applied distributed modelling at regional scale to evaluate the impacts on groundwater recharge and crop yields using long term weather data. The experiments showed that threats arise from continuous monotone land use. Opportunities are created when a proper balance is found between supply and demand of soil water using a larger differentiation of land use. Increasing the areas of land use types with higher evapotranspiration, like permanent grassland and trees, will contribute to a more stable hydrologic system with more water storage capacities in the soil system and lower groundwater levels. Modelling tools clearly support the evaluation of the impact of land use and climate change on groundwater levels and crop yields.

Instituto de Clima y Agua

Author affiliation: Kroes, Joop. Wageningen University and Research. Chair Soil Physics and Land Management; Holanda

Author affiliation: van Dam, Jos. Wageningen University and Research. Chair Soil Physics and Land Management; Holanda

Author affiliation: Supit, Iwan. Wageningen University and Research. Chair Water Systems and Global Change; Holanda

Author affiliation: De Abelleyra, Diego. INTA. Instituto de Clima y Agua; Argentina

Author affiliation: Veron, Santiago Ramón. INTA. Instituto de Clima y Agua; Argentina

Author affiliation: de Wit, Allard. Wageningen University and Research. Wageningen Environmental Research. Unit Earth Observation and Environmental Informatics; Holanda

Author affiliation: Boogaard, Hendrik. Wageningen University and Research. Wageningen Environmental Research. Unit Earth Observation and Environmental Informatics; Holanda

Author affiliation: Angelini, Marcos Esteban. INTA. Instituto de Suelos; Argentina. Wageningen University. Soil Geography and Landscape group; Holanda. International Soil Reference and Information Centre. World Soil Information; Holanda.

Author affiliation: Damiano, Francisco. INTA. Instuto de Clima y Agua; Argentina

Author affiliation: Groenendijk, Piet. Wageningen University and Research. Wageningen Environmental Research, Unit Sustainable Soil Use; Holanda

Author affiliation: Wesseling, Jan. Wageningen University and Research. Chair Soil Physics and Land Management; Holanda

Author affiliation: Veldhuizen, Ab. Wageningen University and Research. Wageningen Environmental Research. Unit Soil, Water and Land Dynamics; Holanda