Journal of Agricultural Studies ISSN 2166-0379 2021, Vol. 9, No. 1 http://jas.macrothink.org 357 Reduction of Sample Size in the Soil Physical-Chemical Attributes Using the Multivariate Effective Sample Size Letícia Ellen Dal Canton (Corresponding author) Western Paraná State University – UNIOESTE Rua Universitária, 1619, Cascavel, Paraná, 85819-170, Brazil Tel: +55 (45) 3220-7320 E-mail: leticiacanton@hotmail.com Luciana Pagliosa Carvalho Guedes Western Paraná State University – UNIOESTE Rua Universitária, 1619, Cascavel, Paraná, 85819-170, Brazil Tel: +55 (45) 3220-7320 E-mail: luciana.guedes@unioeste.br Miguel Angel Uribe-Opazo Western Paraná State University – UNIOESTE Rua Universitária, 1619, Cascavel, Paraná, 85819-170, Brazil Tel: +55 (45) 3220-3228 E-mail: miguel.opazo@unioeste.br Received: August 4, 2020 Accepted: September 29, 2020 Published: January 25, 2021 doi:10.5296/jas.v9i1.17473 URL: https://doi.org/10.5296/jas.v9i1.17473 Abstract Financial investment with collection and laboratory analysis of soil samples is an important factor to be considered when mapping agricultural areas with soybean planting. One of the alternatives is to use the spatial autocorrelation between the sample points to reduce the number of elements sampled, thus restricting the collection of redundant information. This work aimed to reduce the sample size of this agricultural area, composed of 102 sample points, and use it to analyze the spatial dependence of soil macro- and micro- nutrients, as well as the soil penetration resistance. The agricultural area used in this study has 167.35 ha,