Soil Moisture-Monitoring Devices In Field Experiments

The Fieldscout TDR 100 Soil Moisture Probe was compared to the Watermark Soil Moisture Meter that uses sensors placed six inches below the soil surface. We compared the cost effectiveness, portability, ease of use, and accuracy.  We used both devices for monthly evaluations on Hibiscus plants being watered either every two days or every four days in a field experiment. Data was collected when the plants were both stressed (prior to an irrigation event) and unstressed (the day of an irrigation event). Based on data collected, there was no significant difference on the portability or the accuracy of both devices. The Fieldscout TDR 100 was easier to use due to the fact that it was not necessary to find the sensors to hook up to a meter as was done with the Watermark. The Fieldscout cost was $645.00 for the Probe and $48.00 for the rod, while the Watermark Meter cost was $278.00 for the meter and $32.00 for each sensor. For this experiment thirty-six sensors were used at an original cost of $1152.00. However, in the course of the experiment some had to be replaced adding to an additional cost.