|Wertz, D - DEPT. GEOLOGY & GEOPHYSIC|
|Lesmes, D - DEPT. EARTH & ENVI. SCIE.|
Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: January 27, 2004
Publication Date: April 24, 2004
Citation: Lesmes, D., Wertz, D., Gish, T.J., Dulaney, W.P. 2004. Predicting soil moisture dynamics and crop yield using electrical geophyscial methods [abstract]. EOS Transactions, American Geophysical Union, 85(17), Joint Assembly Supplements Abstracts H14A-05. Technical Abstract: Our research at the USDA's Agricultural Research Center (OPE3 field site) located in Beltsville, MD is motivated by the need to develop efficient and non-invasive methods for characterizing the soil properties that control soil moisture dynamics and crop yield. Soil moisture dynamics are controlled by hydraulic conductivity and soil water retention rate, which in turn are controlled by the soil texture (sand and clay content). In this study, we use time-domain reflectometery (TDR) and ground-penetrating radar (GPR) to measure the spatial and temporal variability in soil moisture on an experimental corn field. Electromagnetic induction (EM) and induced polarization (IP) measurements are observed to be highly correlated with soil texture, and can therefore be used to make high-resolution soil texture maps. We have found that the correlation of crop yield with the geophysically derived soil texture maps depends on the overall soil water availability. For example, the crop yield is positively correlated with clay content in 1999 (drought year), but is negatively correlated with clay content in 2000 (wet year). This ground based geophysical methodology provides a framework for the prediction of soil moisture dynamics and its effects on crop yield, and may allow for the optimization of fertilizer and pesticide applications so as to minimize non-point source pollution.