No tillage (NT) is generally associated with high levels of crop residues on soil surface, which has positive effects on physical and chemical fertility, soil biology and erosion control. However, the absence of soil cover 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 for winter crops in the years 2011, 2012 and 2013.The study area included the southwest of Buenos Aires province (SOB), Argentina, where over 120 fields under NT were sampled. Our objectives were: i) to establish a simple methodology for surface residues sampling; ii) to determine the current status of surface residues and soil cover in cropped fields under NT in the SOB; iii) to establish the relationship between amount of surface residues and soil cover for the predominant crops of the 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, most of winter crops (56%) left adequate soil cover while, in average, summer crops did not leave the minimum of 30% soil cover. The analyzed data show the difficulty in the region for the production of dry matter and its permanence as soil cover, even in agricultural fields with continuous no-tillage.
López F.M., M.E. Duval, J.M. Martínez, J.A. Galantini. 2015. Cobertura en el Sudoeste Bonaerense en suelos bajo siembra directa. Ciencia del Suelo 32 (2) 273-281.
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