Publications - Faculty - Recently Submitted Faculty Publications 2008
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Parsons - Soil Science Society American Journal
Lawrence R. Parsons and Wije Bandaranayake
Abstract. Rapid population growth and increasing urban demand reduces the availability of water for agriculture in Florida. Water holding capacity of sandy soils in the Central Florida Ridge area is very poor (<0.10 m3 m-3). Improved soil water monitoring probes can help growers manage irrigation more efficiently and conserve water. This study evaluated a new soil water probe (ECH2O EC-5 sensor, Decagon Devices) in terms of probe-to-probe signal variability, response to fertilizer-induced salinity and changes in soil temperature, soil volume sampled, sensitivity to pockets of air or dry soil, and performance in the field. Results were compared with the already-tested earlier version of a Decagon probe, the EC-20. Results indicated that the new probe has several advantages. The EC-5 was not sensitive to salinity or temperature fluctuations. Probe output change was almost zero when the salinity of the soil was increased to a soluble solids concentration of 14,000 mg kg-1 by adding fertilizer. When temperature was changed gradually from 1.7 to ~38 οC, probe output increased only by about 1%. Soil volume sampled by the probe was about 15 cm3. Probe response was minor when soil cores up to 0.95 cm in diameter near the probe surface were removed. Probes responded well to changes in soil water content in the field. EC-5 probe output increased when bulk density was increased from 1.1 to 1.6 Mg m-3. Probe-to-probe output signal and response to bulk density variations can affect the estimation of field water content unless necessary correction factors are utilized.
