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.
Alvarez, C. R., Costantini, A. O., Bono, A. F., Taboada, M. A., Gutiérrez Boem, F. H., Fernández, P. L., & Prystupa, P. (2011). Distribution and vertical stratification of carbon and nitrogen in soil under different managements in the Pampean region of Argentina. Revista Brasileira de Ciencia do Solo,35, (6),p.1985-1994
10.1590/S0100-06832011000600015
Alvarez, Carina Rosa,Costantini, Alejandro Oscar,Bono, Angel Alfredo,Taboada, Miguel Angel,Gutiérrez Boem, Flavio Hernán,Fernández, Patricia Lilia, et al.. 2011. "Distribution and vertical stratification of carbon and nitrogen in soil under different managements in the Pampean region of Argentina". Revista Brasileira de Ciencia do Solo 35, no.6:1985-1994.
Recuperado de http://ri.agro.uba.ar/greenstone3/library/collection/arti/document/2011alvarez