Project Name: 
Cesium 137 Soil Tracing: Long term soil erosion assessment on rangelands using fallout isotopes

Collaborators:
V. Polyakov, M.A. Nearing, J. Zhang, S. Van Pelt, J.C. Ritchie, O. Crouvi, M. Nichols

Goals/purpose:

Estimating soil erosion on rangelands is crucial for sustaining ecosystem health and guiding effective landmanagement. Soil loss and redistribution threaten the stability of semiarid and arid landscapes, impacting nutrient cycling, vegetation, and water resources. Soil samples collection from a vertical profile in a deposition pond Our work addresses this challenge by applying fallout isotope techniques - specifically, the use of radioactive Cesium-137 and Lead-210 - to quantify erosion and deposition rates across rangeland watersheds in southeastern Arizona. These isotopes, deposited from atmospheric sources, bind to soil particles and serve as tracers, enabling time-integrated assessments of soil movement over decades. By analyzing their distribution in soil profiles, we identified patterns of erosion linked to vegetation changes, anthropogenic activity, and conservation structures at plot, slope, and watershed scales. Importantly, this technique provides a spatially distributed picture of soil loss, allowing us to pinpoint problem areas where intervention is most needed. The resulting data also deliver critical input for soil erosion modeling, enhancing our ability to simulate and predict erosion dynamics. This approach enhances our ability to monitor rangeland health, understand ecological transitions, and support sustainable land stewardship.

Related content:

• Crouvi, O., Polyakov, V.O., Pelletier, J.D., Rasmussen, C., 2015. Decadal-scale soil redistribution along hillslopes in the Mojave Desert. Earth Surface Dynamics 3(2), 251-264. https://esurf.copernicus.org/articles/3/251/2015/esurf-3-251-2015.pdf

• Dunagan, S., Polyakov, V., Keel, T., 2013. Preliminary 210Pb Sedimentation Rates on the Upper Blue Basin of Reelfoot Lake. Northwest Tennessee, Geological Society of America Abstracts with Programs, pp. 783.

• Malone, M., Polyakov, V., 2020. A physical and social analysis of how variations in no-till conservation practices lead to inaccurate sediment runoff estimations in agricultural watersheds.

• Progress in Physical Geography: Earth and Environment 44(2), 151-167. https://journals.sagepub.com/doi/full/10.1177/0309133319873115

• Polyakov, V., Nearing, M., Stone, J., Holifield Collins, C., Nichols, M., 2016a. Quantifying decadal-scale erosion rates and their short-term variability on ecological sites in a semi-arid environment. Catena 137, 501-507. https://www.tucson.ars.ag.gov/unit/Publications/PDFfiles/2296.pdf

• Polyakov, V., Nichols, M., Cavanaugh, M., 2024. Determining sediment deposition dynamics influenced by check dams in a semi‐arid mountainous watershed. Earth Surf. Process. Landf. 49(6), 1849-1857. https://onlinelibrary.wiley.com/doi/abs/10.1002/esp.5802

• Polyakov, V., Nichols, M., Nearing, M., 2016b. Determining soil erosion rates on semi-arid watersheds using radioisotope-derived sedimentation chronology. Earth Surf. Process. Landf. 42(6), 987-993. https://onlinelibrary.wiley.com/doi/abs/10.1002/esp.4057

• Ritchie, J.C., Nearing, M.A., Nichols, M.H., Ritchie, C.A., 2005. Patterns of soil erosion and redeposition on Lucky Hills Watershed, Walnut Gulch experimental watershed, Arizona. Catena 61(2-3), 122-130. https://www.tucson.ars.ag.gov/unit/Publications/PDFfiles/1669.pdf

• Van Pelt, S., Hushmurodov, S., Baumhardt, R., Chappell, A., Nearing, M., Polyakov, V.O., Strack, J., 2017. The reduction of partitioned wind and water erosion by conservation agriculture. Catena 148, 160-167. https://www.sciencedirect.com/science/article/abs/pii/S0341816216302636

• Voli, M.T., Wegmann, K.W., Bohnenstiehl, D.R., Leithold, E., Osburn, C.L., Polyakov, V., 2013. Fingerprinting the sources of suspended sediment delivery to a large municipal drinking water reservoir: Falls Lake, Neuse River, North Carolina, USA. J. Soils Sediments 13(10), 1692-1707. https://www.tucson.ars.ag.gov/unit/Publications/PDFfiles/2240.pdf

• Zaharescu, D.G., Hooda, P.S., Burghelea, C.I., Polyakov, V., Palanca-Soler, A., 2016. Climate change enhances the mobilisation of naturally occurring metals in high altitude environments. Sci. Total Environ. 560, 73-81. https://www.sciencedirect.com/science/article/abs/pii/S0048969716306817

• Zhang, X.C., Polyakov, V., Liu, B.Y., Nearing, M.A., 2019. Quantifying geostatistical properties of 137Cs and 210Pbex at small scales for improving sampling design and soil erosion estimation. Geoderma 334, 155-164. https://www.tucson.ars.ag.gov/unit/Publications/PDFfiles/2493.pdf