Cropping systems with no-tillage and cover plants (CPCS) is a common practice in the region of the Cerrados in Brazil. To better understand the benefits of such a practice, we carried out a study to quantify the water and nitrogen balances of 3 different cropping systems (1 conventional system (T0) and 2 CPCS (T1 and T2)) in Santo Antonio de Goias (Brazil). The main terms of the water and nitrogen balances (soil hydraulic properties, nitrogen content, crop and cover plant biomass, soil mineralisation, cover plant decomposition) were measured during a one year experiment. The results showed a better water conservation with T2 and T1 than with T0, mainly due to a higher water infiltration rate. Nitrogen was more efficiently recycled by the cover plant in T1 and T2, than with T0 where N leaching was high. (Resume d'auteur)