02859nab a2200325 i 4500 BR-BrBNA 20250508122623.0 250508b2020 bl.mr|pooa||| 00| 0 eng | BR-BrBNA eng P33 Guedes, Rafael Silva Alleoni, Luís Reynaldo Ferracciú Correia, Benedito Luiz Alves, Luis Wagner Rodrigues Ramos, Sílvio Junio Fernandes, Antonio Rodrigues Tillage systems and cover plants change organic fractions of phosphorus in oxisol of eastern Amazonia Publicação on-line; 43 ref.; 4 tables; Sumaries (En) ABSTRACT: Due to the large extent of degraded areas in the Amazon, the use of conservation systems is very important to contain the advance of the agricultural frontier, and may favor the availability of nutrients such as phosphorus (P). This study evaluated effect of tillage systems on and cover plants distribution of organic P fractions (Po) in oxisol under soybean and grasses in crop successions. The experimental design was completely randomized with four replicates and five treatments: (i) conventional tillage (CT) with annual soil tillage; (ii) no-till (NT) in succession with Urochloa ruziziensis (NT1); (iii) NT in succession with U. brizantha (NT2); (iv) NT in succession with Panicum maximum (NT3); and (v) a control consisting of a fragment of native vegetation (NV). The Po fractions were quantified at depths of 0-5, 5-10, and 10-20 cm, before and after soybean cultivation and the P fractions were analyzed. The samples at a depth 0-5 and 5-10 cm had increased levels of biomass P in the NT1 and NT2. In addition, at depths of 0-5 and 5-10 cm, the treatments in no-tillage systems accumulated the most of the Po labile fractions. These results showed that conservation systems tend to accumulate most of the P fractions in soil through decomposition of organic residues. Thus, no-tillage system was shown to be important for Po supply, where the use of U. brizantha ‘Piatã’ (NT2) favored higher levels of organic P in labile and moderately labile fractions in soil, which was considered the best alternative for Po supply among the species tested. Key words: Glycine max, organic phosphorus fractionation, humic fractions, no-till. SOJA GRAMÍNEA ANÁLISE DO SOLO SISTEMA DE CULTIVO AMAZÔNIA PLANTA DE COBERTURA 1365 344637 Campinas-SP Instituto Agronômico - Coordenadoria da Pesquisa Agropecuária 1941 2024-4959 Bragantia (Brazil) 0006-8705 v. 49 p. 434-446; (2020) BR2025001025 https://www.scielo.br/j/brag/a/LpmjtN9mSswVdJdncWGSDvb/?format=pdf&lang=en ANA 331383 331383