ELECTRICAL RESISTIVITY AS A PROXY TO SOIL VARIABILITY IDENTIFICATION

• Grant number: 11/24189-0
• Support Opportunities: Regular Research Grants
• Duration: September 01, 2012 - August 31, 2014
• Field of knowledge: Agronomical Sciences - Agricultural Engineering - Agricultural Machinery and Implements
• Principal Investigator: José Paulo Molin
• Grantee: José Paulo Molin
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Soil characterization is important in the establishment of agronomic practices that provide economic and environmental safe food production. Water retention, porosity, cation exchange capacity and texture are soil properties related to each other and can be used to define environments with varying yield potential. Soil samplings followed by standardized laboratory analysis are the usual method to obtain these parameters. Spatial variability of such soil properties requires a large number of samples to be taken, implying in high costs. Soil electrical resistivity can be used as a proxy to characterize such soil parameters. Electrical resistivity measurement of soils can be obtained using equipment developed to agricultural applications. Such equipment have been used with success on the definition of regions of production fields that has distinct soil characteristics. As a large number of soil properties influences electrical resistivity and as the equipment readings obtained with such devices cannot be attributed to a well-defined volume of soil, it is difficult to define which of the properties or even if only one property has the prevailing effect on the resistivity measured. This research is aimed on the development of a method to check the effects of soil texture, moisture and porosity on the readings of electrical resistivity. The method should allow measurements on undisturbed soil samples from distinct soils. A second objective is to compare localized soil resistivity measurements, done with a reference meter along soil profiles, in fields under production, to those obtained using the traditional measurement procedure, in which the measurements are made only on the soil surface. (AU)