Location of Sampling Stations: Grid B-16 behind the stone house. The soil on the sites is an Irwin silty clay loam with approximately 15% slope. Sixty-four, 12 x 12 meter plots are arranged in a split-split design to measure burning, mowing, and fertilization effects.
Frequency of Sampling: Once per year, in the fall, every five years.
Variable Measured: Unless otherwise noted, the methods were used in measuring the variables listed below follow the procedures in 'Recommended Chemical Test Procedures for the North Central Region', Bulletin 499, North Dakota Agricultural Experiment Station, North Dakota State University, Fargo, North Dakota (1980) found in Appendix D.
- Nitrate and Exchangeable NR+ 4. A 10:1 mixture of 2 M KCl and soil are shaken for one hour and filtered. Nitrate and ammonium are measured using Technicon Autoanalyzer.
- Available P (Bray).
- Total-N (Kjeldahl).
- pH (1:1 water)
- Organic matter
- Exchangeable K, Ca, Mg; Cation Exchange Capacity. Five grams of soil are suspended in 50 mL of 1 M NH4OAc for 25 minutes, centrifuged, and filtered. This process is repeated three times. The suspension is washed with ethanol, centrifuged, and finally extracted with 2 M KCl. Exchangeable K, Ca, and Mg are determined in the original ammonium acetate washings, and CEC determined by measuring the residual NH4 in the KCl extract.
- DTPA-Extractable Cu, Zn, Mn, and Fe.
Methods: To avoid destructive over-sampling, all scientists on the Belowground Plots use the same samples. A composite of several 5 cm cores are taken from each plot, and sub-samples distributed to each investigator. A 50 g sub-sample is generally plenty for soil chemical analysis. Samples are air dried, ground to pass a 2 mm sieve, and stored in plastic containers for future analyses.
For additional metadata information see: http://lter.konza.ksu.edu/sites/default/files/DC.pdf
For additional methods information see: http://lter.konza.ksu.edu/sites/default/files/MM.pdf
