Youngmeyer Ranch is located in Elk County, KS (outlet location: 37.56442, -96.49106) and managed by Witchita State University and owned by the Youngmeyer Trust. The ranch is roughly 1902 ha of grassland prairie used predominantly for cattle grazing and is burned every 1-2 years. A tributary of the Elk River, specifically the south branch of the Elk River headwaters, elevation at Youngmeyer ranges from 373-488 m with mean annual temperature of 13.7°C and mean annual precipitation of 979mm. This site is geologically constructed of Permian age limestone and shale with layers of chert below silty clay loam soils (Houseman et al. 2016). This site is predominantly grassland composed of the same dominant grasses as Konza Prairie, with scattered black oaks (Q. veluntina) along the creeks (Houseman et al. 2016).

Houseman, G. R., M. S. Kraushar, and C. M. Rogers. 2016. The Wichita State University biological field station: Bringing breadth to research along the precipitation gradient in Kansas. Transactions of the Kansas Academy of Science 119(1):27-32.

We collected samples every ~3 weeks from 2021 to 2024 at the outlet of our watershed (ENM01, approach 1), seasonally at seven distributed sites (approach 2), and at 43 sites across the watershed between 2021- 2024 .
Samples were filtered in the field with a 0.45um PES filter and acidified to 2% nitric acid for preservation until analysis. Immediately prior to analysis, samples were filtered with a 0.2um PES filter. Aqueous concentrations of cations were determined using coupled plasma-atomic emission spectrometry (ICP-AES) (Horiba Ultima 2, Horiba Jobin Yvon) fitted with an AS 500 autosampler. The instrument has a glass concentric nebulizer equipped with a cyclonic chamber. The generator power is 1000 W. The plasma and auxiliary gas flow rate are 12 L/min and 0 L/min. The sheath gas flow rate and nebulizer are 0.2 and 0.8 L/min. Argon pressure is 80 psi. Multi-elemental standards are prepared in 2% nitric acid as well.

Intermediate tab has data from all triplicates; final data shows only triplicate average, st dev, and RSD (relative st dev). RSD (relative standard deviation is included in intermediate tab; red color indicates values above 10%). We recommend that users use what is presented in the final data tab, as not every replicate has been accounted for and the data has been cleaned.

Low standard for each analyte (below): our lab uses this as the conservative detection limit/LOD. Na - 0.5 ppm / Ca - 0.5 ppm / B - 0.02 ppm / Mg - 0.5 ppm / Si - 0.5 ppm / K - 0.2 ppm / Sr - 0.05 ppm. Note: Boron (B) is almost always below our lowest standard. Most of this data is not useable/below our minimum standard.