ABSTRACT:
Time domain reflectometry (TDR) has changed the way researchers measure soil water content. A technology similar to TDR, called frequency domain reflectometry (FDR) can now be applied to practical field situations, such as irrigation scheduling. For this study, mobile FDR probes were inserted into the soil vertically and measured soil moisture in the upper 0.6m of soil in two 0.3 m increments. The mobile FDR was used to measure soil moisture in many locations in three crops (corn, soybean, spring wheat) on selected days for two growing seasons. This information was used to update a checkbook method of irrigation scheduling and proved to be easy. Quick, mobile FDR measurements in several locations provided sound estimates of soil moisture throughout a field and allowed for enhanced water use efficiency and reduced leaching potential.
Footnotes
Carrie A.M. Luboski is a support scientist with the U.S. Department of Agriculture, Agriculture Research Service in St. Paul, Minnesota. John A. Lamb is associate professor in the Department of Soil, Water, and Climate at the University of Minnesota in St. Paul. Robert H. Dowdy and John M. Baker are a soil scientists with the U.S. Department of Agriculture, Agriculture Research Service in St. Paul. Jerry Wright is an extension agricultural engineer in the University of Minnesota's Department of Biosystems and Agricultural Engineering at the West Central Experiment Station in Morris, Minnesota.
- Copyright 2001 by the Soil and Water Conservation Society
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