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 with a 0.45um PES filter and frozen until analysis. Aqueous concentrations of anions were determined using an IC-3000 IC system (Dionex, Sunnyvale, CA) equipped with Dionex AERS 500 suppressor (2 mm, Thermo Scientific) and Dionex AS auto-sampler (Thermo Scientific). A Dionex IonPac AS15 column (2 mm × 50 mm, Thermo Scientific) with a guard column Dionex IonPac AG15 (2 mm × 50 mm, Thermo Scientific) was used to separate anions using a mobile phase of 38 mM KOH and a flow rate of 0.3 mL/min. The column temperature is 30 °C. Chromeleon software 7.1 is used for system control. Final data tab shows average of triplicates collected in the field and st dev of triplicates. Any NO3 values below 0.01 mg/L are below the lowest standard used in lab analysis and should be interpreted with caution.

The final data tab includes QA/QC’d averaged data for fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate in ppm with standard deviations. If the sample is below detection (BD), it is denoted as that and highlighted pink. Average NAs indicate analytes were not run or that samples were missing. NA’s in the standard deviations columns could indicate that those samples were not run or that only replicate was able to be analyzed.