with the objective of evaluating and selecting cover crops to improve soil management in vineyards (vitis vinifera l.) cv. cabernet sauvignon, five cover pastures were evaluated: a) control without vegetation; b) control with spontaneous vegetation; c) legume mixture of early maturing cultivars of subterranean clover (trifolium subterraneum l.) and burr medic (medicago polymorpha l.); d) legumes mixture of late maturing cultivars of subterranean clover and balansa clover (t. michelianumsavi); and e) legumes mixture of late maturing cultivars and annual ryegrass (lolium rigidum gaud.). the study was conducted at cauquenes experimental center, agriculture research institute (inia), over two seasons, 2005-2006 and 2006-2007. the experimental design was randomized blocks with four replicates. the three pasture mixtures had a good establishment and achieved high populations. biomass production was significantly higher (p ≤ 0.05) in the mixtures with late maturing cultivars of subterranean clover and balansa clover, compared to the mixture of early maturing cultivars of subterranean clover and burr medic (2.3 to 4 t dm ha-1 yr -1 and 5.3 to 6.2 t dm ha-1 yr -1 in the first and second year, respectively). the contents of n, p and k in the biomass of the cover crops were higher (p ≤ 0.05) than those covers with spontaneous species, which allowed for increasing the content of available n in the soil. as well, higher contents of k and p were detected in the soil. the over crops exercised an important detrimental effect on the population of the spontaneous species that grow in the inter-rows of the vineyard.