|Ehsani, Reza - THE OHIO STATE UNIV|
|Saraswat, Dharmendra - THE OHIO STATE UNIV|
Submitted to: ASAE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 3, 2004
Publication Date: August 3, 2004
Citation: Allred, B.J., Ehsani, R.M., Saraswat, D. 2004. The impact of shallow hydrologic conditions on electromagnetic induction measurement of electrical conductivity in a fine-grained soil [abstract]. ASAE Annual International Meeting. Paper No. 042297. Technical Abstract: Precision agriculture is a growing trend, allowing just the right amount of fertilizer, soil amendments, pesticides, herbicides, and tillage effort to be applied to different areas of the field, thereby optimizing crop yields while reducing input costs. Field crop yield variations are often strongly correlated with spatial soil fertility patterns. The intrinsic fertility of a soil is itself affected by various soil profile properties, such as salinity, organic matter content, cation exchange capacity, grain size distribution, clay mineralogy, claypan/fragipan depth, etc. Apparent soil electrical conductivity (ECa), mapped in situ with electromagnetic induction methods, can potentially be used to gauge spatial changes in soil fertility, since it is influenced by these very same properties. However, transient, shallow hydrologic conditions that result from rainfall or irrigation can also possibly impact ECa. The electromagnetic induction measured ECa impact of shallow hydrologic conditions was investigated with regard to varied water table depths, different values of the soil surface volumetric moisture content, and the presence or absence of frozen ground. The soil at the test plot used to conduct this study was fine-grained and classified as a silty clay. Results indicate that there is a strong correlation between the average test plot ECa and the average soil surface volumetric moisture content. However, the correlation between the average test plot ECa and the average water table depth was weaker. Frozen ground conditions were found to dramatically reduce the average test plot ECa. Finally, the spatial patterns shown in the test plot ECa maps generally remained consistent, regardless of the shallow hydrologic conditions, indicating that soil profile properties dominate the ECa response.