Structural Quality of an Oxisol Under Conventional Soil Tillage and Predecessor Crops in Sugarcane Rotation.

Alternating crops at the time of sugarcane rotation can improve soil physical quality, mainly through the action of the root system. The present study aimed to evaluate the impact of crops on the structural quality of a Latossolo Vermelho Distroférrico (Rhodic Hapludox) in a conventional soil tillage system under sugarcane rotation. The experimental design was a randomized block design, with five replicates. The five studied crops were Crotalaria juncea, Crotalaria ochroleuca, Helianthus annuus (sunflower), Glycine max (L.) Merrill (soybean), and Sorghum bicolor (L.) Moench, sorghum variety saccharine BRS 506, in addition to a fallow treatment. After the vegetative cycle of the crops, undisturbed soil samples were collected at two depths (0.15 and 0.25 m). The predecessor crops to the sugarcane plantation altered the physical water soil attributes at both the evaluated depths. The C. juncea crop increased the least limiting water range, but reduced the soil load-bearing capacity. The sorghum variety saccharine under conventional soil tillage exhibited the highest load-bearing capacities, but was associated with the lowest soil structural quality. [ABSTRACT FROM AUTHOR]