Strategy for catch crop development II. Screening of species undersown in spring barley (Hordeum vulgare L.) with respect to catch crop growth and grain yield

Catch crops are recommended in Sweden as a way of decreasing nitrogen leaching from arable land. In six field trials a total of 118 accessions from 39 species of Poaceae, Fabaceae and "other" families was tested as potential undersown catch crops. Barley yield was used as an indicator of competition. Establishment, height and green-matter production, after harvest of the main crop and in December, were estimated for the accessions. In general, the Poaceae showed the highest green-matter production. but they also had the largest negative influence on barley yield. With Poaceae as a catch crop, the barley yield was reduced by 5-15% for all species except for Agrostis tenuis, Festuca rubra and Holcus lanatus, but these three species had a lower green-matter production than the average of all Poaceae. Of all Poaceae investigated, only one accession of Dactylis glomerata combined high green-matter production with no negative influence on barley yield. In the Fabaceae and the "other" families, 11 out of 27 species had no negative influence on barley yield and of these Trifolium repens, Lotus corniculatus and Cichorium intybus had above-average green-matter production and are, therefore, of special interest for further investigations.