Location: Soil and Water Management Research
Title: Soil water sensors:Problems, advances and potential for irrigation scheduling Authors
Submitted to: Scientific and Technical Review
Publication Type: Other
Publication Acceptance Date: March 14, 2012
Publication Date: March 14, 2012
Citation: Evett, S.R., Schwartz, R.C., Casanova, J.J., Lascano, R.J., Oshaughnessy, S.A., Colaizzi, P.D. 2012. Soil water sensors:Problems, advances and potential for irrigation scheduling. Scientific and Technical Review. 2012 CDROM. Technical Abstract: Irrigation water management has to do with the appropriate application of water to soils, in terms of amounts, rates, and timing to satisfy crop water demands, while protecting the soil and water resources from degradation. In this regard, sensors can be used to monitor the soil water status; and some can be used to calculate irrigation amounts and to decide when to optimally irrigate. This presentation consists of two parts: (1) a review and comparison of different electromagnetic (EM) soil water sensor technologies (capacitance or frequency domain and time domain) with attention to accuracy and usefulness for irrigation scheduling, and (2) results of a research project funded by the Ogallala Aquifer Program that focuses on development and testing of a novel waveguide-on-access-tube (WOAT) approach to deep soil profile sensing of water content and bulk electrical conductivity. The frequency domain (capacitance) soil water sensors were found to be too inaccurate and variable for use in irrigation scheduling. The time domain sensors were found to be accurate, though too expensive for routine use and difficult to install deeply, which motivated the research on a lower-cost deep profiling soil water content sensor based on a low-cost TDR circuit.