Volumetric soil water content, measured both by time-domain reflectometry and by thermogravimetric anaysis, for 120 point locations within limestone cedar glades at Stones River National Battlefield near Murfreesboro, Tennessee

This dataset contains data collected within limestone cedar glades at Stones River National Battlefield (STRI) near Murfreesboro, Tennessee. This dataset contains measurements of volumetric soil water content at certain quadrat locations (points) within 12 selected cedar glades. For points at which soil water content was measured by thermogravimetric analysis (oven-drying), which are points indicated by the code OD in the field SWC_Meth, the soil-water-content values contained in this dataset are identical to those for the matching dates and points in the file STRI_Glades_Soil_Water_Content_OD.shp. For details on the procedure used to calculate volumetric soil water content using the thermogravimetric method, see the description paragraph in the metadata section of the dataset STRI_Glades_Soil_Water_Content_OD.shp. For points at which soil water content was measured by portable time-domain reflectometry (points for which the field SWC_Meth has the code TDR), the values in this dataset represent the oven-drying equivalent of the time-domain-reflectometry-measured soil water content values in the file STRI_Glades_Soil_Water_Content_TDR.shp, calculated using a specially-formulated calibration curve (described below). For details on the procedure used to measure volumetric soil water content using the portable time-domain-reflectometry method, see the description paragraph in the metadata section of the dataset STRI_Glades_Soil_Water_Content_TDR.shp. To enable comparisons of soil water content between points which were measured using different methods (time-domain-reflectometry at some points and oven-drying at others), a calibration curve was established between the two methods. Forty-eight paired measurements used to establish the calibration curve were obtained on four dates: November 10, 2011; November 15, 2011; January 15, 2013; and May 29, 2013. Calibration measurements were obtained separately, and on separate days, from routine field visits. However, the methods employed to obtain calibration measurements by time-domain-reflectometry and thermogravimentric methods were identical to those described in the metadata sections of STRI_Glades_Soil_Water_Content_TDR.shp and STRI_Glades_Soil_Water_Content_OD.shp, respectively. Soil-water-content measurements by both methods were natural-log transformed prior to fitting a linear calibration curve. The R-squared value for the calibration curve was 0.9547 and the equation established between the two methods, which was subsequently used to convert time-domain-reflectometry measurements to thermogravimetric equivalents, was: Ln (SWC_OD) = 1.6881 (Ln (SWC_TDR)) – 2.7187, where SWC_TDR is the volumetric soil water content measured by time-domain-reflectometry (expressed as volumetric percent) and SWC_OD is the volumetric soil water content calculated from bulk density and gravimetric soil water content as measured by oven drying (also expressed as volumetric percent).Detailed descriptions of experimental design, field data collection procedures, laboratory procedures, and data analysis are presented in Cartwright (2014).References:Cartwright, J. (2014). Soil ecology of a rock outcrop ecosystem: abiotic stresses, soil respiration, and microbial community profiles in limestone cedar glades. Ph.D. dissertation, Tennessee State University.Cofer, M., Walck, J., and Hidayati, S. (2008). Species richness and exotic species invasion in Middle Tennessee cedar glades in relation to abiotic and biotic factors. The Journal of the Torrey Botanical Society, 135(4), 540–553.

Tags: environment, geoscientificinformation, usgs-55afd0f4e4b09a3b01b51f74
Organization: Department of the Interior