Use of geochemical fingerprints to trace sediment sources in an agriculture catchment of Argentina

TORRES ASTORGA, R.; DERCON, G.; VELASCO, H.; BORGATELLO, G.; MABIT, L.

Roma

Simposio; Global Symposium on Soil Erosion; 2019

FAO

AbstractThis research focuses on the identification of suitable soil tracers from hot spots of land degradation and sediment fate in an agricultural catchment of central Argentina with erosive loess soils. Using EnergyDispersive X-Ray Fluorescence (EDXRF) for geochemical characterization, element concentrations were used as soil tracers. Tracers were first identify using two artificial mixtures composed of known proportions of soil sources collected in different sites with distinctive soil uses. Phosphorus, iron, calcium, barium, and titanium were recognized for obtaining a suitable reconstruction of the source proportions in the artificial mixtures. Later, these elements and the total organic carbon were applied for identifying critical hot spots of erosion in the catchment. Feedlots were identified to be the main source of sediments, river banks and dirt roads together are the second most important source. This research provided a key information for improving soil conservation strategies and selecting land management practices and land uses that do not contribute considerably to sediment redistribution.