Introducción de cultivos de cobertura en la rotación soja-maíz: efecto sobre algunas propiedades del suelo

silt loam soils of the rolling pampas cultivated with soybean and, secondarily, corn under no-tillage (nt) show a progressive decline in their physical and chemical fertility. the inclusion of cover crops (cc) in these agricultural systems could help mitigate these types of degradation. the objectives of this study were: 1) to evaluate the effect of different cc on some soil properties (porosity distribution, structural stability, bulk density, soil organic carbon (soc) and labile carbon) and 2) to analyze the evolution of these properties during the inclusion of cc in a soybean-corn rotation under nt. in 2005, a two-year study was carried out on a silt loam typic argiudoll using different winter species as cc: barley (hordeum vulgare l.), ryegrass (lolium multiflorum l.), oats (avena sativa l.), rescue grass (brumus unioloides l.), vetch (vicia sativa l.), rape seed (brassica napus l.) and forage radish (raphanus sativus l.), a mixture of vetch and oats, and a control without cc. we measured an increase in soil macroporosity and structural stability and an increase in soc content and the labile fraction. these changes were of moderate to low magnitude, occurring mainly near the soil surface (0-5 cm); they were associated with moments of important residue contributions and disappeared in periods of heavy rain. the rotations that included cc accumulated more soc. forage radish outstanded as a generator of porosity and oats as a stabilizer of the porous system.