NUKLEONIKA 2006, 51(2):125-129
Luiz F. Pires, Osny O. S. Bacchi, Nivea M. P. Dias
Center for Nuclear Energy in Agriculture,
The University of São Paulo, C. P. 96, C. E. P. 13.400-970, Piracicaba, SP, Brazil
Gamma-ray beam attenuation is a non-invasive technique that permits analysis of soil porosity
without disturbing the region of interest of the core sample. The technique has as additional
advantage to allow measurements point by point on a millimetric scale in contrast to other methodologies
that are invasive and analyze the soil properties in the bulk sample volume. Soil porosity can be
used as an important parameter to quantify soil structural damages, which affect soil aeration,
water movement and retention. In this study, porosities of three soils different in texture were
measured at various positions in order to analyze the impact of the sampling procedure on the
structure of each particular soil texture. The gamma-ray attenuation system consisted of an 241Am
radioactive source having an activity of 3.7 GBq, collimated with cylindrical lead collimators of
2 mm diameter. The results obtained show the presence of dense regions near the edges of samples
and that different soil textures can suffer distinct deformations at sampling.