Transport of Rare Earth Element-Tagged Soil Particles in Response to Thunderstorm Runoff

Abstract

The downslope transport of rare earth element-tagged soil particles remobilized during a spring thunderstorm was studied on both a natural prairie and an agricultural field in southwestern Iowa (U.S.A.). A technique was developed for tagging natural soils with the rare earth elements Eu, Tb, and Ho to approximately 1,000 ppm via coprecipitation with MnO2. Tagged material was replaced in target locations; surficial soil samples were collected following precipitation and runoff; and rare earth element concentrations were determined by inductively coupled plasma mass spectrometry. Diffusion and exponential models were applied to the concentration-distance data to determine particle transport distances. The results indicate that the concentration-distance data are well described by the diffusion model, butthe exponential model does not simulate the rapid drop-off in concentrations near the tagged source. Using the diffusion model, calculated particle transport distances at all hillside locations and at both the cultivated and natural prairie sites were short, ranging from 3 to 73 cm during this single runoff event. This study successfully demonstrates a new tool for studying soil erosion.

Short‐term erosion rates from a 7Be inventory balance

“…The study was conducted at an experimental field at the National Soil Tilth Laboratory, Deep Loess Research Station in Treynor, Iowa. The field has been a site of several previous soil loss studies (Spomer et al, 1985;Kramer and Alberts, 2000;Matisoff et al, 2001;Whiting et al, 2001). Field W-11 (41°10′00″ N, 95°38′37″ W) has an area of 6 ha with a maximum flow path of 380 m and a slope of 10 per cent ( Figure 1).…”

Multi‐year tracking of sediment sources in a small agricultural watershed using rare earth elements

“…Rare earth elements (REEs), which are elements of atomic number 57 through 71, with similar chemical properties, have been successfully used as a multi-sediment tracer (Liu et al, 2004;Mahler et al, 1998;Matisoff et al, 2001;Wei et al, 2003;Zhang et al, 2003). REEs are nearly uniformly incorporated into Multi-year tracking of sediment sources in a small agricultural watershed using rare earth elements different sizes of soil aggregates for loess-derived silt loam soils, and direct mixing of REEs does not substantially change the physicochemical properties of soil aggregates (Zhang et al, 2001).…”

Quantifying sediment transport across an undisturbed prairie landscape using cesium-137 and high resolution topography

“…Long-standing efforts to determine average erosion rates across agricultural landscapes involve the construction of small-scale runoff plots (Roels, 1985), monitoring of suspended sediment concentrations in streams draining the landscapes (Steegen et al, 2001), and, with recent analytical breakthroughs, through the use of sediment tracers (Matisoff et al, 2001) or short-lived isotopes (Matisoff et al, 2002a,b). Collection and analyses of soil from runoff plots or suspended sediment analyses remains problematic primarily because of the difficulties with ensuring a closed system, while injection of tracers onto agricultural lands immediately imparts a short-term measurement bias.…”