Soil management practices affect its attributes which will further affect crop development. It is generally known and accepted that soil surface compaction occurs in no tillage system and that this compaction tends to increase with time. However, most of the research do not evaluate adequately soil physical properties behavior as affected by time of management. The objective of this work was to evaluate spatial variability of soil bulk density and soil porosity on a Rhodic Eutrudox under no tillage with annual crops for twenty years. The work was conducted in Campinas, São Paulo State, considering the period between 1985 and 2005. The attributes analyzed in this study were: clay (g kg-1), silt (g kg-1), sand (g kg-1), soil bulk density (kg dm-3), soil porosity (%), macroporosity (%) and microporosity (%). Geostatistics was used to analyze the data and the spatial variability maps of compaction and porosity of soil attributes. The sampling conducted in 1985 was unable to detect the spatial variability of density and porosity of the soil. The physical attributes sampled in 2005 showed large ratio of spatial dependence. The maps of spatial variability did not show a clear link between the texture, soil bulk density and soil porosity. After 20 years no tillage management the area did not present problems of compaction. No tillage influenced favorably the spatial variability of soil attributes sampled in 2005.
soil physical attributes; soil management; geostatistics
