ASABE Technical Library - Abstract

Abstract.

The knowledge of soil spatial variability is an important step for applying precision agriculture. One of the attributes widely used to represent soil spatial variability is the apparent electrical conductivity. A portable soil sensor system was developed to measure the soil apparent electrical conductivity using a four-electrode approach. As soil is a complex system that presents a nonlinear behavior, the developed system measures the electrical conductivity using alternating current at frequencies of 11.7, 20.7, 30.3 and 45.5 Hz. A low cost GNSS sensor was integrated in the system to provide the GPS position of each data point. The system was centered on a very low-cost BeagleBone Black board and development platform. A user interface was developed in C++ and a touch screen with a resolution of 800x480 pixels was used to display the results and present summary statistics of the data already collected. The system also does a preliminary spatial data analysis by calculating the semivariogram parameters and by generating an error map of the kriging interpolation. The user can check in real-time if the acquired data is OK, or if some extra points need to be added to improve the representation of the spatial variability of the measured soil attributes. The system provides a low-cost and flexible system to quickly map soil apparent electrical conductivity.