The influence of soil properties on denitrifying bacterial communities and denitrification potential in no-till production farms under contrasting management in the Argentinean Pampas

SILVINA M ROSA; FILIPE B KRAEMER; MARCELO A SORIA; LEANDRO D GUERRERO; HÉCTOR J MORRÁS; EVA L FIGUEROLA; LEONARDO ERIJMAN

APPLIED SOIL ECOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 75 p. 172 - 180

0929-1393

Abstract: The aim of this work was to investigate the response of the structure, abundance and potential activity of denitrifiers under contrasting agricultural management in no-till production fields, across a regional scale within the highly productive Argentine northern Pampas. Treatment categories were grouped according to the sustainability of the soil management, in terms of crop rotation, fertilization, agrochemicals use and pest control, as good no-till agricultural practices (GAP) and poor no-till agricultural practices (PAP). Non-cultivated soils in each geographic location were also evaluated as reference groups. Mixed models, with sites treated as random factors, indicated that the potential denitrification activity and the size of the nirS community differed significantly between non-cultivated and PAP soils. Soil properties whose variances were mainly affected by agricultural management (referred as dynamic properties) were distinguished from those in which the main variance could be attributed to edaphicclimatic differences between sites (i.e. inherent properties). Dynamic properties could explain the changes in potential denitrification activity, but not the changes in the abundance of denitrifiers. Results from principal components analysis suggested site-specific response of most dynamic soil properties. Among the latter, only the aggregate stability indices AS1 and AS3 were strongly associated with potential denitrification activity after removing the geographical effect.