Análise da condutividade elétrica aparente do solo por indução: perspectivas das correlações com os elementos físicos e químicos do solo em áreas de cultivo de cana-de-açúcar

Abstract

The sampling and analysis of agricultural soils are important processes for characterizing the physical and chIEMcal properties of agricultural soil. The soil apparent electrical conductivity (CEa) is influenced by several interrelated properties, and considers spatial variability in its measurements. Seeking to understand possible correlations between the values of CEa in the soil and the results of soil sampling, two experiments were carried out, located in different regions in the state of São Paulo, with different soil classes. Using the EM38-MK2® electromagnetic induction (IEM) sensor, it was possible to perform measurements in the entire area of interest, with a high data density, which were superimposed on the representative areas of each soil sample collected in a regular grid, resulting in a mean CEa value for each soil sample. Thus, strong, moderate and weak positive and negative correlations were seen between the physical and chIEMcal elements of the soil and the CEa, measured in two depth ranges (0.75 m and 0.375 m). The most significant correlations were observed between CEa and physical attributes (fine sand, coarse sand, total sand, silt and clay), especially in experimental area 1. As for chIEMcal attributes, additional studies should be carried out to demonstrate their efficiency of measurement, since opposite results were found at different depths of measurements by the sensor, mainly in sandy textured soil.