Assessment of the physical quality of a Fluvisol in the Brazilian semiarid region

In Brazil, the physical quality of soils has been frequently investigated using the S index (idS); however, information regarding the quality of other important agricultural soils such as Fluvisols is lacking. Therefore, this study aimed to evaluate the soil physical and hydraulic interaction with idS and determine how these properties are distributed spatially in a Fluvisol from Parnamirim, located in the semiarid region of Pernambuco. Soil water retention θ(h) and hydraulic conductivity K(θ) curves were generated using 30 samples from the soil surface by using the Beerkan method. The parameter θ(h) was used to determine the idS for each sample; subsequently, Pearson's correlation and geostatistic analyses were conducted to determine the properties that were significantly correlated with idS. The idS showed an average value below that considered as reference for soils with good physical quality and had significant correlation only with available water (θavbl), owing to the presence of meso- and micropores and clay, sand, and coarse sand contents. Thus, the soil physical quality measure S index alone was not sufficient to evaluate accurately the physical quality of the Fluvisol.