Performance Analysis of Factory, Laboratory, and Field Calibrated Soil Water Sensors and Their Effect on Irrigation Scheduling.

In the semi-arid climate of west central Nebraska proper management of soil water availability is required to prevent over or under irrigating of crops, which may lead to negative economic and environmental consequences. Direct methods for quantifying soil water status can be destructive, tedious, time consuming, expensive, limited by physical constraints, and non-continuous in nature, and therefore, indirect technologies have been developed to estimate soil water status. Unfortunately, these indirect methods can be influenced by various factors, such as soil physical properties, which can result in poor performance of their factory calibrations and may require site specific laboratory or field calibrations. Through research at the University of Nebraska-Lincoln West Central Research and Extension center (UNL-WCREC) the performance of various soil water sensors types, including electrical resistance, neutron attenuation, frequency domain reflectometry, time domain reflectometry, and capacitance based, were evaluated to determine the accuracy of each sensor and their potential impact on irrigation management when using the factory calibration equations as compared with site-specific laboratory and field calibration equations. The performance analysis, along with recommendations for the area will be presented.