hosphorus speciation and distribution in a variable-charge Oxisol under no-till amended with lime and/or phosphogypsum for 18 year

Author(s)

Firmano, Ruan F. ^[1] ; Colzato, Marina ^[1] ; Alleoni, Luis R. F. ^[1]

Affiliation

^[1] Univ Sao Paulo, Luiz de Queiroz Coll Agr ESALQ, Soil Sci Dept, Padua Dias Av 11, BR-13418000 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: European Journal of Soil Science; v. 73, n. 1 DEC 2021.
• Web of Science Citations: 0

Abstract

Long-term management with lime and/or phosphogypsum (PG) can change phosphorus (P) forms across the soil profile. In this study, we used synchrotron-based spectroscopy and sequential chemical fractionation to investigate P chemical species after long-term (18 years) application of amendments in a subtropical Oxisol. The availability of nutrients increased with the combined use of lime and PG and a stratification of attributes was identified due to long-term broadcast applications. X-ray absorption near edge structure (XANES) spectra profiles revealed the predominance of P bounded to haematite (Hm) (48% on average) and also P bound to kaolinite (32% on average) species. Low proportions (16%) of calcium-phosphates in the uppermost soil layer (0-5 cm) were found in the treatment that received high calcium (Ca) inputs by lime and PG broadcast. Few correlations were identified between the proportions of P species obtained by XANES and P fractions operationally defined by sequential chemical fractionation (SF). Our results suggest that P-species bound to kaolinite can store stable P forms, which correlated (p < 0.05) with the residual P fractions obtained by SF, highlighting the importance of kaolinite as a legacy P store in Oxisols. Highlights Lime and phosphogypsum broadcast under no-till improve soil fertility and P availability. Labile and moderately labile P fractions were the only ones influenced by lime and/or phosphogypsum. Proportions among P bounded to Fe- and Al-(hydr)oxides with different structural may be affected by long-term Al-suppressors. P-species bounded to kaolinite may store stable P forms in Oxisols. (AU)

• FAPESP's process: 18/08586-8 - Broadcast application of limestone and phosphogypsum and the phosphorus forms of an oxisol under no-till
• Grantee: Ruan Francisco Firmano
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/11063-7 - Lime and phosphogypsum in long-term no-till: soil quality improving crop physiology and 15N-fertilizer recovery in the soil-plant system
• Grantee: João William Bossolani
• Support Opportunities: Scholarships in Brazil - Doctorate