Mapping depth to gravel using electromagnetic induction method in wild blueberry fields
Authors: Khan, F, Q Zaman, A Schumann, A Madani, D Percival
Description: Wild blueberry soils are rocky in nature and the root zone depth of this crop is approximately 10-15 cm. There is a gravel layer beneath the soil surface. The objective of this study is to estimate and map the depth to gravel strata and to assess the effect of gravels on the crop yield using electromagnetic induction (EMI) method. EMI is gaining popularity due to its non-destructive nature, rapid response and ease of integration. Two wild blueberry fields were selected in central Nova Scotia. A grid pattern of sampling and/or yield points was established at each experimental site. Soil samples were collected from established grid points at 0-15, 15-45 and 45-75 cm depths and analyzed for coarse aggregates. The apparent ground conductivity (ECa) was measured and recorded with DualEM-2 at the same grid points. A small C++ program was written in Microsoft Visual Studio 2010 to develop mathematical models for estimating the gravel depth using the two output values of DualEM-2. Comprehensive surveys were conducted in the fields to measure the ECa. The accuracy of the estimated values from the models was calculated using root mean square error (RMSE). The RMSE (0.27 m, Field 1 and 0.2 m, Field 2) indicated that this procedure was good enough in predicting gravel depth. The 3-D maps were generated for predicted gravel depth from EMI survey data in ArcGIS software. The maps showed substantial variation in selected fields. This information will help to develop strategies to improve crop production.
Keywords: interface depth, gravel, emi, dgps, gis, apparent ground conductivity, dualem
Technical field: technical_fields_app7
Session name: Soil and water