A field study was carried out from May of 1993 to May of 1995 at Federal University of Santa Maria campus at the Soil Science Department experimental área, using an experiment installed on a typic Hapludalf (yellow-red podzolic) since 1989. The objectives were to evaluate the impact of some winter cover crops on water aggregate stability afterfour andfive year ofno- tiliage system. The cover crops used were: forage pea (Pisum arvensis), common vetch (Vicia saliva), wild winter pea (Lathyrus sativus), ryegrass (Lolium multiflorum Iam), blue lupine (Lupinus angustifolius) and black oat (Avena strigosa). The fallow was used as a control treatment. Soil samples to measure aggregate stability were extracted from 0 to 5cm depth atfour dates ofeach year: (l st) - cover crops atflowering; (2nd) - after com emergency; (3rd) - com tasseling and; (4th) - com harversting. In 1993/94) growing season the treatment with black oat cover crop induced higher water aggregate stability than other cover crops. However, for the following year ali cover crops inproved the aggregate stabilty to a levei wich was not observed significant dijference among then.
aggregate stability; cover crops; no-tiliage
