Beschreibung:
<jats:title>ABSTRACT</jats:title><jats:p>Introduction of the fructan crops root chicory (<jats:italic>Cichorium intybus</jats:italic> L.; RC) and Jerusalem artichoke (<jats:italic>Helianthus tuberosus</jats:italic> L.; JA) into agricultural production systems is desirable to diversify crop rotation. Field experiments were conducted to compare the agronomic performance of RC and JA with sugar beet (<jats:italic>Beta vulgaris</jats:italic> L.; SB). One set of cultivars during 1995, 1996, and 1997 and an additional set in 1997 were grown on a sandy loam soil (Haplic Luvisol) at Braunschweig, Germany. Crops were cultivated with and without supplemental irrigation, complete and no weed control (1995 and 1996), and N fertilization rates of 0, 60, and 120 kg ha<jats:sup>−1</jats:sup> Severe water stress caused significant but similar storage organ yield losses in all crops, whereas mild water stress mainly affected JA yields. Averaged across years and N levels, storage organ yield losses through weed competition under irrigation amounted to 70, 47, and 8% in SB, RC, and JA, respectively. Averaged across years, in the absence of water and weed stress, SB, RC, and JA at their respective optimal N levels gave root and tuber dry matter yields of 14.8, 15.0, and 11.5 Mg ha<jats:sup>−1</jats:sup>, and sugar yields of 11.5, 11.2, and 8.1 Mg ha<jats:sup>−1</jats:sup>, respectively. Maximal SB and JA yields generally were achieved at the highest N rate, while RC peak yields were attained at 60 kg N ha<jats:sup>−1</jats:sup> With the same amount of N taken up, RC in 1995 and SB in 1996 and 1997 produced the highest sugar yields.</jats:p>