TDR use on tropical soil as affected by probe characteristics and installation conditions

Abstract

Although soil moisture is defined by a single physical concept, its determination is not necessarily simple. Since such determination is necessary to soil-water management studies and practices, direct and indirect methods have been developed. Although the Time Domain Reflectometry (TDR) technique has been widely used in recent years, research has shown that prior calibration must be undertaken before the use of this technique. Scanty information exists for tropical soils. Research was undertaken on a Rhodic Kandiudalf, commonly found in the northeast region of the state of Paraná, Brazil. Present study detects the effects of probe characteristics and of soil moisture conditions at the moment of probe installation on the TDR measurements. Installation effects was much more important than probe characteristics. Soil water content during probe installation process affects TDR readings, probably affecting soil-probe contact