Location: Sustainable Water Management ResearchTitle: Soil moisture sensor test with Mississippi Delta soils
|PRINGLE, H - Mississippi State University|
|BARNES, E - Cotton, Inc|
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2019
Publication Date: 4/25/2019
Citation: Sui, R., Pringle, H.C., Barnes, E.M. 2019. Soil moisture sensor test with Mississippi Delta soils. Transactions of the ASABE. 62(2):363-370.
Interpretive Summary: One of the methods for irrigation scheduling is to use soil moisture sensors to measure soil moisture levels in plant root zone and apply water if there is water shortage for plants. USDA-ARS Scientist at Crop Production Systems Research Unit in Stoneville, MS, working with his collaborators, tested measurement accuracy and repeatability of sixty-six soil moisture and soil temperature sensors with six types of Mississippi Delta soil. The sensor calibration was conducted for measuring soil water content. Results of this study showed the soil moisture sensors were capable of detecting general trend of the soil moisture changes. However, the accuracy of sensor measurements varied by sensors and soil types. For accurate measurements, the soil moisture sensor requires soil-specific calibration. The temperature sensors performed very well in the test. Soil temperature could be consistently and reliably determined using the sensors. Information obtained from this work can be used to develop sensor-based irrigation scheduling methods for crop production.
Technical Abstract: One of the methods for irrigation scheduling is to use soil moisture sensors measuring soil moisture level in plant root zone and apply water when there is water shortage for plants. Measurement accuracy and reliability of the soil moisture sensor are critical for the sensor-based irrigation management. This study evaluated the measurement accuracy and repeatability of the EC-5 and 5TM soil volumetric water content (SVWC) sensors, MPS-2 and 200SS soil water potential (SWP) sensors, and 200TS soil temperature sensor. Six 183cm x 183cm x 71cm wooden compartments were built inside a greenhouse, and each compartment was filled with one type of soil from the Mississippi Delta. Sixty-six sensors with 18 data loggers were installed in the soil compartments to measure SVWC, SWP, and soil temperature. Soil samples were periodically collected from the compartments to determine SWVC using gravimetric method. SVWC measured by the sensor was compared with that determined by the gravimetric method. SVWC readings of the sensors have a linear correlation with the gravimetric SVWC (r2=0.82). The correlation was used to calibrate the sensor readings. The SVWC and SWP sensors were capable of detecting general trend of soil moisture changes. However, their measurements varied significantly among the sensors and were influenced by soil property. To obtain accurate absolute soil moisture measurements, the sensors require soil-specific calibration. The 5TM, MPS-2, and 200TS sensors performed well in soil temperature measurement test. Individual temperature readings of those sensors were very close to the mean of all sensor readings.