| ARTICLES | Am. J. innov. res. appl. sci. Volume 2,  Issue 7, Pages 305-312 (July 2016)

Research Article    IN SITU COMPARISON OF THREE SOIL MOISTURE SENSORS IN DRIP IRRIGATED SANDY LOAM SOILS     | Ahmed Zakaria Dewidar |. Am. J. innov. res. appl. sci. 2016; 2(7):297-304.    | PDF FULL TEXT |                                                                   |Received | 01 July 2016|          |Accepted | 02 July 2016|         |Published 10 July 2016 |

Abstract      Background: Understanding the patterns of soil moisture distribution is useful to a wide range of agencies concerned with the weather and climate, soil conservation, agricultural production and landscape management. Objective: The study was to evaluate the ability of three different soil sensors to capture the correct pattern of soil water contents under field conditions using the gravimetric method as a reference. Material and methods: Three commonly used soil water sensors were tested in a sandy loam soil located at the educational station of King Saud University, Saudi Arabia. The tested soil moisture sensors were EnviroSCAN, WaterMark and Tensiometers. Results: Based on the analysis statistics, the results showed among the tested sensors, EnviroSCAN performed the best with a smallest mean difference (MD), relative root mean square error (RRMSE %), standard deviation (SD) and relative bias (Re %) of -0.67, 10.68, 0.051 and -4.06, respectively as compared to gravimetric method. Tensiometers obtained the largest values in MD, RRMSE (%), SD and Re (%) of 0.40, 13.97, 0.058 and 1.83, respectively. WaterMark performed averagely with regard to MD, RRMSE, SD and Re as compared to gravimetric method. Conclusion: The dynamic response of the vertically installed EnviroSCAN to changes in soil water content was the best among the tested sensors. The sensor may be used as a useful tool for assessing threshold values in water content for the start and end of irrigation. Keywords:   EnviroSCAN, soil moisture sensors, sensor performance