Effect of no tillage in the stabilization of soil organic carbon at site scale in Santiago del Estero, Argentina

Abstract

Currently 90% of Argentine agriculture is done under no-tillage agriculture (zero tillage) and there is scarce information about trends over time of forms of soil organic carbon (SOC) in NE sites. from Santiago del Estero, Argentina (Chaco Semi-Arid). Here we describe and explain changes in the content of COS, particulate organic carbon (COP), organic carbon associated with the mineral phase (COA), potentially mineralizable carbon (C0), mineralization rate (kc) and C stock under no-tillage from 3 to 17 years in depths of 0.05 and 0.20 m. It is concluded that the land use change of native polyphytic deciduous forest to no-tillage agriculture reduces C stock and the forms of greater lability, increases the rate of mineralization, stabilizing them over time, since land clearing causes increases in the mineralization of COS due to different contribution in amount and quality of litter, being litter of crops of smaller quantity and greater lability. This constitutes an important risk for conservation of Chaco semi-arid ecosystems, with emphasis on soil resource as a basis for primary productivity and confirming the susceptibility of these ecosystems to disturbances such as deforestation.