Growth of legume and nonlegume catch crops and residual-N effects in spring barley on coarse sand

Summary

The aim of this experiment was to investigate the growth and residual-nitrogen (-N) effects of different catch-crop species on a low–N fertility coarse sandy soil. Six legumes (white clover [Trifolium repens L.], red clover [Trifolium pratense L.], Persian clover [Trifolium resupinatum L.], black medic [Medi-cago lupulina L.], kidney vetch [Anthyllis vulneraria L.], and lupin [Lupinus angustifolius L.]), four non legumes (rye grass [Lolium perenne L.], chicory [Cichorium intybus L.], fodder radish [Raphanus sativus L.],and sorrel [Rumex Acetósa L.]), and one mixture (rye/hairy vetch [Secale cereale L./Vicia villosa L.])were tested in a field experiment with three repli-cates in a randomized block design. Four reference treat-ments without catch crops and with N application (0, 40, 80, and 120 kg Nha–1) to a succeeding spring barley were included in the design. Due to their ability to fix N2, the legume catch crops had a significantly larger abovegrounddry-matter production and N content in the autumn than the non legumes. The autumn N uptake of the nonlegumes was 10–13 kg Nha–1 in shoots and approx. 9 kg ha–1 in the roots. The shoot N content of white clover, black medic, red clover, Persian clover, and kidney vetch was 55–67 kg ha–1, and the root N content in white clover and kidney vetch was approx. 25 kg ha–1. The legume catch crops, especially white and red clover, seemed to be valuable N sources for grain production on this soil type and their N fertilizer-replacement values in a following unfertilized spring barley corresponded to 120 and 103 kg Nha–1, respectively. The N fertilizer–replacement values exceeded the N content of shoots and roots.