Physical, chemical and structural attributes of soil in agroecosystems in the Brazilian Semiarid region

Resumo

The soil attributes can be easily changed according to its management and use, compromising the productive capacity of the
areas. The objective of this research was to evaluate the variability and interrelationships of soil physical, chemical and structural attributes in
agroecosystems in the Brazilian Semiarid region (Rio Grande do Norte State), pointing out the most sensitive attributes in the environment
distinction through multivariate analysis. The research was carried out in the rural community of Piracicaba, Upanema municipality, Rio Grande
do Norte State, Brazil. Four agroecosystems were selected: Native Forest Area (ANF), Corn Bean Consortium Area (ACBC), Pasture Area
(AP) and Cashew Area (AC). Undisturbed and deformed soil samples were collected in the 0.00-0.10, 0.10-0.20 and 0.20-0.30 m layers,
and the physical, chemical and structural attributes were analyzed. The data were submitted to multivariate statistical techniques, using
the correlation matrix, cluster analysis, factor analysis and principal component analysis. Factorial analysis revealed the most sensitive
attributes in distinguishing agroecosystems: microporosity, fi eld capacity (FC), permanent wither point (PWP), available water (AW),
sand, clay, fl occulation degree (GF), Ca2+, Mg2+ and sum of bases (SB) (F1) and soil density (SD), total porosity (PT), macroporosity,
electrical conductivity (EC) and total organic carbon (TOC) (F2). Cluster analysis formed three distinct groups. The TOC was discriminant
to group the native forest and cashew tree areas, showing the infl uence of soil management. The other environments were grouped
according to the texture differentiation, infl uencing the attributes variability.