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ARS Home » Midwest Area » West Lafayette, Indiana » National Soil Erosion Research Laboratory » Research » Publications at this Location » Publication #394940
Research Project: Assessment of Sediment and Chemical Transport Processes for Developing and Improving Agricultural Conservation Practices

Location: National Soil Erosion Research Laboratory

Title: Performance evaluation of a water erosion tracer using plot-scale experiments and process-based modeling

Author
item VILLELA, JOAO - Embrapa
item ANACHE, JAMIL - Universidade De Sao Paulo
item WATANABE, ALEX - Embrapa
item Flanagan, Dennis
item WENDLAND, EDSON - Universidade De Sao Paulo
item CRESTANA, SILVIO - Embrapa

Submitted to: International Soil and Water Conservation Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2023
Publication Date: 5/16/2023
Citation: Villela, J.M., Anache, J.A., Watanabe, A.M., Flanagan, D.C., Wendland, E.C., Crestana, S. 2023. Performance evaluation of a water erosion tracer using plot-scale experiments and process-based modeling. International Soil and Water Conservation Research. https://doi.org/10.1016/j.iswcr.2023.05.003.
DOI: https://doi.org/10.1016/j.iswcr.2023.05.003

Interpretive Summary: Soil erosion by water is a serious problem throughout the world. New methods to measure locations where soil is detached by raindrops and flowing water, and where sediments deposit back to the soil surface use individual or combinations of rare earth elements (REE) that are not commonly present in soils. The REE can be placed or mixed into parts of a field, and then measured in sediments leaving during rainfall/runoff events, and also measured in sediment downslope of the REE application area. This study used an REE tracer composed of neodymium (Nd3+), lanthanum (La3+), and praseodymium (Pr3+), created from a mining industry waste product in Brazil. The tracer was mixed into a strip of soil near the top of 20 m long plots, and then measured in the plots’ soil and runoff sediments after two rain storm events in 2018. The REE were found both in the runoff sediment, and in locations down the plots, decreasing in amounts with distance downslope away from the application area. The erosion plots were also simulated using a process-based erosion computer simulation model (Water Erosion Prediction Project – WEPP model). There was good agreement between the measured and modeled soil loss values and spatial sediment transport distributions, indicating that this new REE method can be used to monitor sediment movements from rill and interrill erosion processes. These results impact scientists, university faculty, students, and others involved in soil erosion by water measurement and modeling research. Improved methods to measure soil particle detachment, transport, and deposition can improve understanding of the physical processes, and help in development of better mathematical descriptions.

Technical Abstract: Socioeconomic and environmental losses caused by water erosion have highlighted the importance of quantifying and understanding the dynamics of soil redistribution in the landscape to develop effective soil management practices. Several methods are applied to estimate erosion/deposition rates and identify sources of sediments, among them, the one that uses rare earth elements (REE) as a tracer stands out. However, an alternative not yet explored that can benefit the accuracy of the estimates provided by the method is using a tracer containing a chemical signature composed of more than one REE. The present study aimed to evaluate the performance of a new water erosion tracer based on montmorillonite labeled with rare earth elements (La40-MMT). The innovative aspects of this La40-MMT tracer include its highly stable multi-chemical signature (Nd3+, La3+, and Pr3+), which enhances tracer detection in the environment, and its low production cost due to the use of an industrial residue in the synthesis process. The tracer was evaluated for a typical soil of the Cerrado biome, using a natural rainfall field-scale plot - NRFP (5 m x 20 m) and a physical predictive erosion model (WEPP). The results showed that the La40-MMT tracer could be used to estimate erosion/deposition rates, with agreement between the values observed with the tracer and the WEPP model. Thus, this study confirmed the great potential of La40-MMT as a tool to identify patterns of soil redistribution at the field scale and aid in the validation of erosion models.