Phosphorus speciation by P-XANES in an Oxisol under long-term no-till cultivation

Autor(es)

Antonangelo, Joao A. ^[1] ; Firmano, Ruan F. ^[2] ; Zhang, Hailin ^[1] ; Colzato, Marina ^[2] ; Abdala, Dalton B. ^[3] ; Carvalho, Hudson W. P. ^[4] ; de Oliveira Junior, Adilson ^[5] ; Alleoni, Luis R. F. ^[2]

Afiliação do(s) autor(es)

^[1] Oklahoma State Univ, Dept Plant & Soil Sci, 371 Agr Hall, Stillwater, OK 74078 - USA

^[2] Univ Sao Paulo, Luiz de Queiroz Coll Agr, Dept Soil Sci, BR-13418900 Piracicaba, SP - Brazil

^[3] Brazilian Synchrotron Light Lab, BR-13083100 Campinas, SP - Brazil

^[4] Univ Sao Paulo, Ctr Nucl Energy Agr, Lab Nucl Instrumentat, BR-13416000 Piracicaba, SP - Brazil

^[5] Natl Soybean Ctr, Brazilian Agr Res Corp, BR-86001970 Londrina, Parana - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Geoderma; v. 377, NOV 1 2020.
• Citações Web of Science: 0

Resumo

In highly weathered soils with low phosphorus (P) content and high P fixing capacity, long-term application of P fertilizers may influence P speciation. The combined use of macro- and microscopic techniques can provide information on P distribution and reactivity in soils, which is an important key to determine its loss potential into the environment. In this study, we aimed to evaluate the effects of rates of P on solid-state P speciation in an Oxisol under no-till (NT) for 26 years in Brazil. Soil samples were collected from experimental plots that received 0 to 50 kg ha(-1) P annually. X-ray Fluorescence microanalysis (mu-XRF), X-ray Absorption Near-Edge Structure (XANES), and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopies were used along with soil mineralogical and conventional chemical analyses. Phosphorus availability increased with the applied P rates. Based on the mu-XRF analysis, high Pearson correlation coefficients (r) were obtained for P vs Al, Si and Fe contents (r = 0.97, 0.81 and 0.84, respectively, with P < 0.0001); and partial correlation showed co-localized effects mainly for Al and Si. The Fe-EXAFS results hinted to the presence of non-crystalline iron (Fe) minerals being favored in the cultivated soils, likely as a consequence of the higher rates of P applied and utilization by the crops. P-XANES data revealed that after the fertilization, the proportion of P sorbed to goethite did not vary, but the proportion of P sorbed to hematite decreased, while P sorbed to kaolinite increased. The long-term continuous application of P fertilizers beyond plant uptake capacity favored P build-up in soils, resulting not only in poor P use efficiency but also in exacerbated risk of P loss to the environment. (AU)

• Processo FAPESP: 18/08586-8 - Aplicação superficial de calcário e de fosfogesso e formas de fósforo em um latossolo sob semeadura direta
• Beneficiário: Ruan Francisco Firmano
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 15/19121-8 - EMU concedido no processo 2015/05942-0: sistema de microfluorescência de Raios X
• Beneficiário: Hudson Wallace Pereira de Carvalho
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários