Phosphorus adsorption and desorption in undisturbed samples from subtropical soils under conventional tillage or no‐tillage |
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| Authors: | Jessé R. Fink Alberto V. Inda Jovana Bavaresco Vidal Barrón José Torrent Cimélio Bayer |
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| Affiliation: | 1. Department of Soils, Federal University of Rio Grande do Sul, Bento Gon?alves Avenue 7712, 91540‐000, Porto Alegre, Rio Grande do Sul, Brazil;2. Department of Agronomy, University of Córdoba, Edificio C4, Campus de Rabanales, 14071 Córdoba, Spain |
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| Abstract: | The dynamics of P in soil is greatly influenced by the adsorption of phosphate onto Fe‐oxides. Access of phosphate to the surface of these minerals depends on the degree of soil aggregation, which in turn is influenced by soil management system. The primary purpose of this work was to investigate P adsorption and desorption in undisturbed and disturbed soil samples from an Ultisol (Rhodic Paleudult) and an Oxisol (Humic Hapludox) under conventional tillage (CT) or no‐tillage (NT). Phosphorus adsorption and desorption in undisturbed soil was studied by using a continuous flux system containing a P solution for adsorption measurements or deionized water and Mehlich‐I solution for desorption measurements. The Oxisol, which had higher clay, hematite, and goethite contents than the Ultisol, exhibited the highest maximum P adsorption capacity (Pmax) values in disturbed samples. Also, the disturbed Ultisol samples had lower Pmax values under NT than under CT. The undisturbed soil samples exhibited no significant differences in P adsorption between soil management systems, but P desorption was more marked under NT than under CT. The samples of Oxisol under NT exhibited lower P adsorption rates and higher P desorption rates than the CT samples of the same soil. The decreased P adsorption in undisturbed samples relative to disturbed samples suggests that P adsorption is influenced by physical properties of soil. |
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| Keywords: | iron oxides organic carbon soil aggregation soil management phosphate adsorption |
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