The use of no-tillage systems associated with the use of cover crops and crop rotation changes some soil physical properties and may indicate change in soil quality. This study aimed to use the aggregate stability index (IEA) and the sensitivity index (SI) to assess changes in soil physical attributes with the use of different plant cover after twelve years of no-tillage. We used a randomized block design with the following types of cover crops: sunn hemp, millet, sorghum, brachiaria, and fallow (natural vegetation) sampled in 2012, and a control (conventional planting) since 2000, in which three samples were collected per plot for a total of 12 samples per treatment, with four replications. We evaluated soil bulk density (Bd), macroporosity (Ma), microporosity (Mi), total pore volume (TPV), aggregate stability (AS), geometric mean diameter (GMD), mean weighted diameter (MWD), sensitivity index (SI), and index of the percentage of aggregates with diameter greater than 2 mm (AGRI). The use of different crop covers and the introduction of the no-tillage seeding system after twelve years caused positive changes in the physical properties of the soil surface layer. The positive and negative correlations between and significant soil density and the other evaluated physical attributes showed its importance as an indicator of soil quality. Through the sensitivity index, it was observed that microporosity increased more than the other physical attributes after the implementation of the no-tillage system in the area.
no-tillage; aggregation; soil bulk density
