Nitrogen transfers from Vicia sativa L. and Trifolium resupinatum L. to the companion grass and the following crop

The course of N-NO3- concentrations in soil, N transfer from the catch crops Vicia sativa L. and Trifolium resupinatum L. to the companion grass Lolium multiflorum ssp. gaudinii (Parl.) Schinz et Keller, and the preceding crop effect on Lolium multiflorum ssp. italicum (A. Br.) Volkart were studied in a field experiment. Catch crops were sown in pure stands and grass/legume swards (= two species in alternating rows) at two sowing dates and harvested at different dates from August to November. Vicia sativa was more effective concerning N2 fixation than Trifolium resupinatum, this was also evident from above ground N yield and N-NO3- amount of the soil. The factor sowing date had the greatest influence on N yield. N transfer to the companion grass was generally low. Early sown legumes in pure stands and in mixture temporarily caused slightly increased N-NO3- amounts in soil compared with unfertilized grass in winter and following spring, whereas late sown legumes apparently had no effect on N-NO3- amounts. Both legumes had a considerable preceding crop effect in the mixture and in the pure stand for both sowing dates.