Data/hora: 22/06/2024 02:22:12

Biblioteca(s): | Embrapa Agrobiologia.
Data corrente: | 25/10/2007
Data da última atualização: | 18/03/2015
Autoria: | ZOTARELLI, L.; ALVES, B. J. R.; URQUIAGA, S.; BODDEY, R. M.; SIX, J.
Afiliação: | Lincoln Zotarelli, UFRRJ; Bruno José Rodrigues Alves, Embrapa Agrobiologia; Segundo Urquiaga, Embrapa Agrobiologia; Robert Michael Boddey, Embrapa Agrobiologia; Joerg Six, University of California.
Título: | Impact of tillage and crop rotation on light fraction and intra-aggregate soil organic matter in two oxisols.
Ano de publicação: | 2007
Fonte/Imprenta: | Soil & Tillage Research, Amsterdam, v. 95, n. 1-2, p. 196-206, sept. 2007.
Idioma: | Inglês
Notas: | Parceria: Colorado State University, UFRRJ, University of California.
Conteúdo: | It is well known that no-tillage (NT) practices can promote greater stocks of soil organic matter (SOM) in the soil surface layer compared to conventional tillage (CT) by enhancing the physical protection of aggregate-associated C in temperate soils. However, this link between tillage, aggregation and SOM is less well established for tropical soils, such as Oxisols. The objective of this study was to investigate the underlying mechanisms of SOM stabilization in Oxisols as affected by different crop rotations and tillage regimes at two sites in southern Brazil. Soils were sampled from two agricultural experiment sites (Passo Fundo and Londrina) in southern Brazil, with treatments comparing different crop rotations under NT and CT management, and a reference soil under native vegetation (NV). Free light fraction (LF) and intra-aggregate particulate organic matter (iPOM) were isolated from slaking-resistant aggregates. Of the total C associated with aggregates, 79?90% was found in the mineral fraction, but there were no differences between NT and CT. In contrast, tillage drastically decreased LF-C concentrations in the 0?5 cm depth layer at both sites. In the same depth layer of NT systems at Londrina, the concentrations of iPOM-C were greater when a legume cover crop was included in the rotation. At Londrina, the order of total iPOM-C levels was generally NV > NT > CT in the 0?5 cm depth interval, but the difference between NT and CT was much less than in Passo Fundo. At Passo Fundo, the greatest concentrations and differences in concentrations across tillage treatments were found in the fine (53?250 ?m) iPOM fractions occluded within microaggregates. In conclusion, even though no aggregate hierarchy exists in these Oxisols, our results corroborate the concept of a stabilization of POM-C within microaggregates in no-tillage systems, especially when green manures are included in the rotation.
Palavras-Chave: | Agregado do solo; Matéria orgânica do solo; Oxissolo; Rotação de culturas.
Thesaurus Nal: | crop rotation; Oxisols; soil aggregates; soil organic matter.
Categoria do assunto: | --
Registro original: | Embrapa Agrobiologia (CNPAB)
Exemplares: | CNPAB - (34480-1) - UPC - AP - -- -  -  - 0023250 - DIS