Distribuição e estratificação vertical do carbono e nitrogênio em solos sob diferentes manejos na região do Pampa Argentino

• Autores: Alvarez, Carina Rosa; Costantini, Alejandro Oscar; Bono, Angel Alfredo; Taboada, Miguel Angel; Gutiérrez Boem, Flavio Hernán; Fernández, Patricia Lilia; Prystupa, Pablo
• Año de publicación: 2011
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Revista Brasileira de Ciencia do Solo; Vol.35, no.6; 1985-1994; http://www.sbcs.org.br/en/
• Materia: C AND N STOCKS; CARBON STRATIFICATION; NO-TILLAGE; SOIL ORGANIC MATTER FRACTIONS; TILLAGE SYSTEMS
• Institución: Universidad de Buenos Aires. Facultad de Agronomía

Fil: Alvarez, Carina Rosa. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.
Fil: Costantini, Alejandro Oscar. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.
Fil: Taboada, Miguel Angel. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.
Fil: Gutiérrez Boem, Flavio Hernán. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.
Fil: Fernández, Patricia Lilia. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.
Fil: Prystupa, Pablo. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.
One of the expected benefits of no-tillage systems is a higher rate of soil C sequestration. However, higher C retention in soil is not always apparent when notillage is applied, due e.g., to substantial differences in soil type and initial C content. The main purpose of this study was to evaluate the potential of no-tillage management to increase the stock of total organic C in soils of the Pampas region in Argentina. Forty crop fields under no-tillage and conventional tillage systems and seven undisturbed soils were sampled. Total organic C, total N, their fractions and stratification ratios and the C storage capacity of the soils under different managements were assessed in samples to a depth of 30 cm, in three layers (0-5, 5-15 and 15-30 cm). The differences between the C pools of the undisturbed and cultivated soils were significant (p less than 0.05) and most pronounced in the top (0-5 cm) soil layer, with more active C near the soil surface (undisturbed greater than no-tillage greater than conventional tillage). Based on the stratification ratio of the labile C pool (0-5/5-15 cm), the untilled were separated from conventionally tilled areas. Much of the variation in potentially mineralizable C was explained by this active C fraction (R 2 = 0.61) and by total organic C (R 2 = 0.67). No-till soils did not accumulate more organic C than conventionally tilled soils in the 0-30 cm layer, but there was substantial stratification of total and active C pools at no till sites. If the C stratification ratio is really an indicator of soil quality, then the C storage potential of no-tillage would be greater than in conventional tillage, at least in the surface layers. Particulate organic C and potentially mineralizable C may be useful to evaluate variations in topsoil organic matter.