Multiscale analysis of dust emissions from agricultural soils in La Pampa, Argentina

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The province La Pampa (Argentina) is located in the transition zone between pastoral and arable farming. This region is very susceptible to wind erosion and induced dust emissions due to semiarid climatic conditions. The economy-driven, increasing demand for corn and soybean production reinforces land use changes (LUC), mainly a transformation from pastures or forests into arable land. The resulting soil degradation might cause a positive feedback loop by increasing wind erosion and dust emissions as first investigations indicated. The aim of this project is to investigate process dynamics, drivers, quantity and quality of dust emissions from arable land of the La Pampa region in a three-step multi-scale approach: 1. Analysis of stationary and transient dust emission potentials of soils along a chrono-sequence of land use changes (controlled wind tunnel and plot experiments),2. Field-scale quantification of the dynamics of wind erosion (horizontal flux) and induced dust emissions (vertical flux) at two experimental fields (representing different soils) in high spatial and temporal resolution, incl. mass balances, and3. Analysis of the physical, chemical and microbial properties of the emitted dusts. The explicit combination of state-of-the-art lab and field methods across scales is going beyond the previous standards and enables a profound analysis of dust emissions. The horizontal and vertical flux measurements combine standard procedures with state-of-the-art particle counters, which measure dust particles between 0.3 and 30 µm in diameter in 30 classes every 10 seconds. The comprehensive dust characterization includes combined 3D-Laser and Scanning Electron Microscopy (combined with EDX), FTIR-Spectroscopy and microbial fingerprinting techniques (T-RFLP, PCR).The expected results of this project will substantially improve our knowledge on dust fluxes and dust quality from arable land, esp. in properties which are relevant in atmospheric proc-esses. Furthermore, causes and feedbacks between wind erosion, dust emissions and soil deg-radation and soil fertility losses will be understood better than today.