TIME DOMAIN REFLECTOMETRY IN CLOSED CONTAINER STUDIES

Time domain reflectometry (TDR) has been widely utilized to estimate soil water content in field plots, but applications to controlled-environment experiments have not been adequately described. The TDR procedure was used in three closed-container, greenhouse studies to monitor soil moisture levels and dictate watering schedules. In all experiments, TDR was an efficient method for monitoring soil water. Also, estimation of soil water content by TDR was highly correlated to gravimetric analysis of soil cores, with r2 values of 0.84, 0.96, and 0.98 for the three studies. Different soil types, with variabie physical properties and bulk densities, had no apparent effect on estimations of soil water content. It was concluded that TDR could be useful in greenhouse studies to accurately determine soil water content.