LUCERNE IN ARABLE CROPPING SYSTEMS: POTENTIAL OF DIFFERENT VARIETIES ON BIOMASS PRODUCTION AND NITROGEN BALANCE

Lucerne improves yields and quality of subsequent crops by fixing nitrogen and increasing soil organic matter. In the Ukrainian region of Poltava weather conditions have become more difficult for producing legumes over the past decades. While the biomass productivity of modern lucerne varieties is well known, data on the nitrogen fixation capacity are still missing. Therefore biomass and nitrogen fixation capacity of 4 Ukrainian varieties (Lidiya, Poltavchanka, Vira, Zaykevicha) were evaluated in two field trials in two subsequent years. The seasonal average forage yield of lucerne was 10.5-11.4 t ha -1 with no significant differences between the varieties, but with a better performance at 1 st and 2 nd harvest in the second year because of a successful field emergence and water supply. An analysis of the genotype-by-year interaction on two experimental sites indicated that the old varieties Poltavchanka and Zaykevicha were well adapted to the experimental site environment. These varieties gave consistently stable shoot dry matter yields in both vegetation periods. Biological nitrogen fixation (average of 155 kg N ha -1 ) and N-balance (average of -159 kg N ha -1 ) did not differ between the four varieties, therefore the benefit for subsequent crops should be the same or similar.