Location: Watershed Physical Processes ResearchTitle: High-frequency surface waves method for agricultural applications Author
|Lu, Zhiqu - University Of Mississippi|
|Shankle, Mark - Mississippi State University|
Submitted to: Fast Times: News for the Near Surface Geophysical Sciences
Publication Type: Popular Publication
Publication Acceptance Date: 12/1/2017
Publication Date: 12/4/2017
Citation: Lu, Z., Wilson, G.V., Shankle, M. 2017. High-frequency surface waves method for agricultural applications. Fast Times: News for the Near Surface Geophysical Sciences. 22(4):21-25.
Interpretive Summary: In agricultural farm-land management, soil properties near the surface are important because they can be influenced by things like cultivation, freezing, and water runoff. It is desirable to develop techniques that can measure and monitor soil properties without disturbing the soil. A method using high-frequency surface waves has been developed by University of Mississippi and USDA ARS scientists to explore shallow soil. This method is a modification of another method called Multichannel Analysis of Surface Waves or MASW, adapted to use high-frequency surface waves (called HF-MASW). The HF-MASW method explores geological and engineering soil properties to depths of 50 feet. The HF-MASW method has been successfully used for several agricultural applications, including (1) identifying layers in soil profiles, (2) determining weather and seasonal effects on layer properties, (3) identifying naturally dense layers called fragipans, and (4) imaging compaction of layers due to field machinery and rainfall. The HF-MASW method provides geologist, engineers and soil scientist a method to characterize shallow soils for these and potentially other applications without digging-in, probing or otherwise disturbing the soil profile.
Technical Abstract: A high-frequency surface wave method has been recently developed to explore shallow soil in the vadose zone for agricultural applications. This method is a modification from the conventional multichannel analysis of surface wave (MASW) method that explores near surface soil properties from a couple of meters to tens of meters for geotechnical and civil engineering applications. The MASW method is a geophysical and seismic technique based on spectra analysis of one types of surface waves, Rayleigh waves, to determine the shear S-wave velocity profile, i.e. the S-wave velocity as a function of depth. Using high frequencies (HF), up to 1 kHz, the HF-MASW method aims at measuring soil profiles from a few centimeters to several meters deep. In this paper, several agricultural applications of the HF-MASW method were presented, including (1) soil profiling, (2) weather and seasonal effects, (3) fragipan layer imaging, and (4) compaction study.