Revista Brasileira de Ciência do Solo
On-line version ISSN 1806-9657
CAMARGO, Livia Arantes; MARQUES JUNIOR, José; PEREIRA, Gener Tadeu and HORVAT, Renata Alves. Spatial variability of mineralogical attributes of an oxisol under different relief forms: I - clay fraction mineralogy. Rev. Bras. Ciênc. Solo [online]. 2008, vol.32, n.6, pp. 2269-2277. ISSN 1806-9657. http://dx.doi.org/10.1590/S0100-06832008000600006.
The distribution of the clay fraction minerals depends on specific soil-environmental conditions. The study of the relationship between properties of these minerals and specific sites of landscape occurrence is important to understand the relationship between the mineralogy and other soil attributes. This study aimed to evaluate the degree of cristallinity of goethite, hematite, kaolinite and gibbsite and the spatial pattern in an Oxisol under sugar cane for 30 years. In a grid with regular 10 m - intervals, 119 samples were collected at a depth of 0.2-0.4 m. The crystallographic attributes of the minerals were analyzed statistically and geostatistically. Kriging maps were drawn to visualize the spatial variability of attributes. All attributes were spatially dependent, and the mineralogical attributes were related to variations in the relief forms. The largest mean crystal diameter (MCD) among the studied clay minerals was observed for gibbsite, and the greatest variation in the MCD and full width at half maximum in the mineral goethite. The highest values of the MCD of goethite, hematite and gibbsite were found in the compartment II characterized by a concave-convex area.
Keywords : hematite; goethite; kaolinite; gibbsite; geostatistics; kriging.