Variability and correlation among physical properties of an oxisol under no-till and conventional tillage

Soil management systems modify the spatial distribution of soil physical properties. The objectives of this study were to verify the spatial dependency and co-relationship of some soil physical properties by data fitting to individual and cross-semivariograms in an Oxisol (Typic Haplorthox) under no-till and conventional tillage, in Campo Mourão, state of Parana, Brazil. In April 2004, 128 undisturbed soil samples were collected in a 3 x 5 m grid, in the middle of the 5-0.15 m layer. The following soil physical properties were measured: soil bulk density, macroporosity, microporosity, total soil porosity and soil water content at a tension of 100 hPa (field capacity). The spatial variability in the single semivariogram of these soil physical properties was higher and the range in no-tillage was smaller than in conventional tillage. On the other hand, the cross-semivariogram of soil bulk density and total porosity or field capacity indicated spatial co-relationships with lower spatial variability and higher ranges in no-tillage than conventionally tilled soils. The cross-semivariogram suggested that soil bulk density showed a spatial co-relationships with the other soil physical properties in both soil management systems studied.

soil bulk density; soil porosity; spatial variability; cross-semivariogram; no-tillage