N2‐Fixierung und Ertragsstruktur der Weißen Lupine (Lupinus albus L.) im Vergleich zu Vicia faba L. und Glycine max (L.) Merr. auf verschiedenen Standorten

Abstract

Abstract N2‐Fixation and Yield Structure of White Lupin (Lupinus albus L.) in Comparison to Vicia faba L. and Glycine max (L.) Merr. on Different Sites In field studies white lupin (Lupinus albus L., Eldo) was compared with faba bean (Vicia faba L., Herz Freya) in 1986 and soybean (Glycine max [L.] Merr., Gambit) in 1988 on five sites respectively. Total N2‐fixation, which was determined by the extended difference method, and yield components were correlated to weather and soil conditions:1. While faba bean responded to low pH with delayed nodulation, white lupin showed no decrease in N2‐fixation at pH less than 5.5 as far as soil was not calcareous.2. The white lupin developed its root system most quickly into further soil depths and produced a root dry weight six times as large as that of faba bean in the soil layer 60‐90 cm until the end of July (Bayreuth).3. Despite on the calcareous sites the white lupin showed the highest total‐N2‐fixation (max. 36 g N/m2) throughout, the N‐gain for the succeeding crop was up to 8 g N/m2 for white lupin and faba bean as well. In contrast the N‐balance of soybean was mostly negative.4. Seed yields of white lupin (48‐450 g/m2) ranged between those of faba bean (145‐549 g/m2) and of soybean (89‐290 g/m2); its raw protein yields were the highest found (max. 158 g/m2) though.