Evaluation of the FieldScout TDR300 for Determining Volumetric Water Content in Sandy South Georgia Soils

Although time domain reflectometry (TDR) probes have been found to be accurate in most soils, the strength of the relationship between TDR values and soil water content can vary considerably from one soil to the next. This study examined the accuracy of water content measurements taken with a FieldScout TDR300 as compared to volumetric water content determined from samples of known volume. The primary soils sampled in the study are of the Albany, Chipley and Ousley series which have sand or loamy sand textures. Simple linear regression analysis was used to evaluate the relationship between TDR readings and volumetric water content. The slope of the regression line was 1.06 and the R 2 value was 0.70. These values lead to the conclusion that the FieldScout TDR300 provided reasonable estimations of soil water content in the soils investigated and would be appropriate to use in certain situations. However, the FieldScout TDR300 may not be appropriate for use in these soils if a high degree of water content accuracy is essential or if readings are needed from depth within the soil.