CONDUTIVIDADE ELÉTRICA APARENTE, ATRIBUTOS DO SOLO E VARIABILIDADE ESPACIAL DE PRODUTIVIDADE DAS CULTURAS DE MILHO E FEIJÃO

Abstract

The Apparent Electrical Conductivity (CEa) is an indirect method that is being used to quantify the spatial variability of the productive potential of agricultural crops and consequently to recommend agronomic practices, by be able to identify the variability of important physical and chemical characteristics of the soil such as water availability, variations in texture, density, porosity and cation exchange capacity. This work aimed to identify the physical and chemical soil attributes that has correlation with crop yields, verify which of these attributes are being detected by CEa as well to check for correlation between CEa and crop yield behavior of a Brown Latosol. The study was conducted in 2015-2016 in a commercial field with 51,55 hectares in Modelo Farm, municipality of Candói, which had historical crop yield maps. The CEa was obtained by parallel passes with Veris MPS3 every 30 m. The collection points were directed in 4 productive potential classes, denominated as low, medium low, medium high and high. In each of these classes, the soil collection and evaluation of chemical and physical attributes was made in 3 depths, 0 to 15, 15 to 25 and 25 to 40 cm, determined according to the homogeneity of the penetration resistance previously raised in the area. How were raised 39 variables, we opted for the multivariate statistical method, applying the factor analysis, performing the extraction of the factors by principal component analysis. In the three depths, the attributes responsible for the quality of soil physical structure, such as low density and high porosity, were most related with crop yields, in order to benefit there. The same attributes relate to CEa in order to limit the passage of electrical current and thus provide lower conductivity values. In the intermediate and deeper layers, the CTC and organic matter content were also related to crop productivity in order to benefit it. The crop yields and CEa were inversely related.