Surface liming effects on soil radiation attenuation properties

• Published in: Journal of soils and sediments 2018-04, Vol.18 (4), p.1641-1653
• Main Authors: Ferreira, Talita R., Pires, Luiz F., Brinatti, André M., Auler, André C.
• Format: Article
• Language: English
• Subjects: Acidic soils; Acidity; Aluminum; Americium isotopes; Atomic properties; Attenuation; Attenuation coefficients; Bulk density; Caesium 137; Calcium; Calcium ions; Cesium isotopes; Cesium radioisotopes; Chemical modification; Clay; Coherent scattering; Composition; Earth and Environmental Science; Electron density; Energy; Energy consumption; Environment; Environmental Physics; Extinction coefficient; Hydrogen; Incoherent scattering; Lime; Liming; Magnesium; Mathematical analysis; Organic carbon; Parameters; Pasture; pH effects; Photoelectricity; Physical properties; Porosity; Procedures; Sec 5 • Soil and Landscape Ecology • Research Article; Software; Soil; Soil chemistry; Soil classification; Soil density; Soil layers; Soil lime; Soil pH; Soil physical properties; Soil porosity; Soil properties; Soil Science & Conservation; Soil sciences; Soil surfaces; Soils; Subsoils; Variation
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-017-1866-2

Purpose This study investigates the effects of surface liming on soil attenuation radiation properties. For this, measurements of soil chemical attributes (pH, organic carbon, H+Al, Al 3+ , Ca 2+ , and Mg 2+ ) and attenuation radiation parameters (mass attenuation coefficient, μ m , atomic and electronic cross sections, σ a and σ e , effective atomic number and electron density, Z eff and N el ) were carried out. This aim was motivated by the fact that possible μ m variation might cause as well variation in the determination of soil physical properties. Materials and methods The studied soil, classified as a Dystrudept sity-clay, is located in South Brazil. The trial consisted of five stripes, one of them under pasture and the remaining under no-till system (NTS). Lime rates of 0, 10, 15, and 20 t ha −1 were broadcast on the NTS soil surface. Disturbed soil samples were collected 30 months after liming at the top (0–10 cm) and subsoil (10–20 cm) layers. Soil chemical attributes were characterized following standard experimental procedures. The soil oxide composition, obtained by EDXRF analysis, was used to calculate μ m for 241 Am and 137 Cs photon energies with XCOM computer code. μ m values were employed to calculate σ a , σ e , Z eff , and N el and to predict variations in soil bulk density (ρ) and total porosity (φ). Results and discussion Surface liming notably increased contents of soil pH, Ca 2+ , and Mg 2+ while reduced H+Al and Al 3+ at the top soil layer, where μ m , σ a , σ e , and Z eff were also increased with the lime rates. However, at the subsoil layer, liming neither lessened soil acidity nor induced remarkable changes in the attenuation parameters. When using 137 Cs photon energy, incoherent scattering totally dominated over the radiation interaction processes whereas photoelectric absorption and coherent scattering substantially contributed when 241 Am photon energy was used. Therefore, the increasing in soil attenuation parameters at the top soil layer was more accentuated considering 241 Am than 137 Cs photon energy. Variation in μ m caused considerable variation in ρ and φ only for 241 Am photon energy. Conclusions The findings regarding the effect of μ m variation induced by liming on the determination of soil physical properties are extremely relevant because traditionally, in the soil science area, μ m values are calculated without considering any chemical modification to which the soil can be submitted. Bearing in mind that ρ and