Evaluation of spatial variation in the soil water content with time domainreflectometry

Spatial variation in the water content on an unplowed plot of 10 by 10 m(2) was evaluated using TDR and gravimetric methods. The results show that bot h methods give similar estimates of the variation in the water content. How ever, the volumetric water content measured by the TDR techniques constitut es 0.974 +/- 0.053 of the gravimetrically measured water content. A correla tion between the bulk density and the gravimetric water content in the 0- t o 5-cm and 5- to 10-cm layers is negative. The correlation of relative elev ation with volumetric water content and bulk density at a sampling point is positive.