EFFECTS OF CLAY FRACTION MINERALOGY ON PHYSICAL ATTRIBUTES OF A YELLOW ULTISOL TREATED WITH CHISELING

Abstract

ABSTRACT The objective of this study was to evaluate the influence of minerals in the clay fraction on physical attributes of Yellow Ultisol cultivated with sugarcane and prepared with two different treatments: chiseling across the entire area and chiseling only in planting rows. The samples were collected from four layers of soil at eight months after planting. We assessed the texture of the soil, levels of iron extracted by dithionite-citrate-bicarbonate (DCB) and ammonium acid oxalate (AAO), ratio of kaolinite/(kaolinite + gibbsite), soil bulk density, and soil penetration resistance. The first area showed a higher ratio of kaolinite/(kaolinite + gibbsite) and the second area had greater levels of iron extracted by DCB. Levels of iron extracted by DCB were inversely correlated with soil bulk density and penetration resistance, while the kaolinite/(kaolinite + gibbsite) ratio was directly correlated with soil bulk density and penetration resistance. The area with a greater kaolinite/(kaolinite + gibbsite) ratio had higher values of soil bulk density and soil penetration resistance and the area with higher levels of iron showed lower values of soil bulk density and soil penetration resistance. The mineralogy influenced the soil's physical attributes, while soil preparation treatments did not.