Resumen

LOPEZ, FERNANDO MANUEL; DUVAL, MATÍAS EZEQUIEL; MARTINEZ, JUAN MANUEL  y  GALANTINI, JUAN ALBERTO. COBERTURA EN EL SUDOESTE BONAERENSE EN SUELOS BAJO SIEMBRA DIRECTA. Cienc. suelo [online]. 2015, vol.33, n.2. ISSN 1850-2067.

No tillage (NT) is generally associated with high levels of crop residues on the soil surface, which has positive effects on physical and chemical fertility, soil biology and erosion control. However, the absence of soil cover under no-tillage may have a worse effect on soil quality in the long term than conventional tillage. In this study, we determined the presence of surface residues and soil cover in fields under winter crops in years 2011, 2012 and 2013. The study area included southwestern Buenos Aires province (SOB), Argentina, where over 120 fields under NT were sampled. Our objectives were to: i) establish a simple methodology for surface residues sampling; ii) determine the current status of surface residues and soil cover in cropped fields under NT in SOB; iii) establish the relationship between amount of surface residues and soil cover for the predominant crops of SOB. A large proportion of fields in the subhumid-semiarid region of SOB had lower soil cover than the required by the literature to be considered conservation agriculture, which would provide adequate protection against erosion. In the studied area, near half of the winter crops left adequate soil cover while, in average, summer crops did not leave the minimum of 30% soil cover. In these sites, the soil cover provided by spontaneous vegetation would increase this percentage. The analyzed data showed the difficulty in the region for the production of dry matter and its permanence the soil cover provided by spontaneous vegetation would be of great importance as soil cover, even in agricultural fields with continuous no-tillage.

Palabras clave : Stubble; Residues; Conservation agriculture.

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