With the purpose of studying the weed suppressive capacity of some cover crops as an alternative for weed control in lucerne ( Medicago sativa) and the effect on its productivity, a study was carried out under field non-irrigated conditions on slightly leached medium-deep chernozem. During the 2005-2007 period, a trial was carried out with the following variants: V 1 - Lucerne ( Medicago sativa), pure stand (PS) - check, zero; V 2 - Lucerne, PS - check, weeded; V 3 - Lucerne, PS - with chemical control; V 4 - Lucerne+cover oat ( Avena sativa); V 5 - Lucerne+cover spring barley ( Hordeum sativum); V 6 - Lucerne+cover rye ( Secale cereale). As a result of the study the following conclusions were drawn: In the systems of environmentally friendly agriculture, the use of some cover cereal crops (spring barley, oat and rye) in the year of establishment of lucerne stands, under favourable agro-meteorological conditions, could be an alternative to conventional technology. The cover crops had a weed suppressive capacity and as a result they decreased weed infestation degree, though to a smaller extent, as compared to chemical control. The cover crops allowed more efficient area use in the first year of lucerne cultivation, when it had a slow rate of growth and development. In spite of lower seed yields from the lucerne stands with cover crops, as compared to the pure stands by conventional technology, they are of interest in ecological aspect. Under the conditions of the concrete study, the cover crops were in the following ascending order according to aggressiveness: spring barley, oat and rye.
