Statistical Multivariate Analysis Applied to Environmental Characterization of Soil in Semiarid Region1

Abstract

Soil is a dynamic and complex system that requires a considerable number of samples for analysis and research purposes. Using multivariate statistical methods, favorable conditions can be created by analyzing the samples, i.e., structural reduction and simplification of the data. The objective of this study was to use multivariate statistical analysis, including factorial analysis (FA) and hierarchical groupings, for the environmental characterization of soils in semiarid regions, considering anthropic (land use and occupation) and topographic aspects (altitude, moisture, granulometry, PR, and organic-matter content). As a case study, the São José Hydrographic Microbasin, which is located in the Cariri region of Ceará, was considered. An FA was performed using the principal component method, with normalized varimax rotation. In hierarchical grouping analysis, the “farthest neighbor” method was used as the hierarchical criterion for grouping, with the measure of dissimilarity given by the “square Euclidean distance.” The FA indicated that two factors explain 75.76% of the total data variance. In the analysis of hierarchical groupings, the samples were agglomerated in three groups with similar characteristics: one with samples collected in an area of the preserved forest and two with samples collected in areas with more anthropized soils. This indicates that the statistical tool used showed sensitivity to distinguish the most conserved soils and soils with different levels of anthropization.

The impact of the Botanical Garden of Oles Honchar Dnipro National University reconstruction on the soil aggregate structure

“…На більшій частині території міста ґрунти істотно відрізняються від природних (P. Wang et al, 2018). Зміна фізико-механічних властивостей відбувається у напрямку підвищення ущільненості та зниження вологоємності (Roithmeier & Pieper, 2009;Oliveira Júnior et al, 2019). Ділянками, де ґрунтовий покрив залишається в малозміненому стані, є охоронні території в межах міста -природні й історичні парки, лісопарки, міські ліси, ботанічні сади.…”

Characterization and Classification of Soils in Agroecosystems in a Moist Enclave in Northeastern Brazil

“…Multivariate statistical techniques can be used to differentiate environments formed by different soil classes by gathering a lower number of variables and clustering samples according to their similarity or difference, showing effectiveness for soil studies [16].…”

Estudo de fatores que interferem na qualidade das aplicações terrestres de produtos fitossanitários

“…Em seguida foi avaliado o grau em que as variáveis estão associadas entre si com a matriz de correlação linear de Pearson (ARAÚJO et al, 2013;OLIVEIRA JÚNIOR et al, 2019) e a normalidade multivariada foi testada tanto na assimetria quanto na curtose usando o teste de Mardia.…”

“…Na sequência foram testados os pressupostos de esfericidade de Bartlett, a medida de adequação da amostra de Kaiser-Meyer-Olkin (KMO). No primeiro caso, testa-se a hipótese que a correlação entre cada par de variáveis é nula, portanto, é preciso que o resultado não ultrapasse o valor da significância, geralmente estabelecida em 0,05 (OLIVEIRA JÚNIOR et al, 2019). No segundo pressuposto, o resultado é a média do teste de adequação ao modelo de cada uma das variáveis, sendo aceitável um índice maior que 0,5 (BEZERRA;CORRAR, 2006;HAIR et al, 2009).…”