THE INTERDEPENDENCE OF WINTER BARLEY AS A COVER CROP AND DIFFERENT UNDERSOWINGS

In view of the establishment of rotational fallows - set aside land - and the bridging of the vegetation-free winter period interactions bet ween cover crop and undersowing were investigated in field trials. The suitability of the cover crop winter barley and different undersowing s as well as varied seed rates was tested; in addition, the microclima te in the stand was evaluated. In some cases yield losses of the cover crop were recorded; causes for the yield reductions were high seed ra tes of Festuca rubra with strong weed growth or lodging. Low seed rate s of the cover crop in combination with high seed rates of undersowing s caused yield losses of the cover crop. Festuca rubra developed well in winter barley; the cultivation of Lolium perenne and Trifolium repe ns is uncertain because of the risk of light and water deficiencies. S trong differences between different seed rates of the cover crop (100 and 400 seeds . m-2) were found for the photosynthetic active radiatio n in the stand, whereas no significant differences were detected for t he relative humidity and temperature.