Bestimmung der N-Fixierung unterschiedlicher Wintererbsengenotypen im Vergleich zu einer Sommererbse in Rein- und Gemengesaat

Summary in the original language of the document

In organic farming the cultivation of leguminous crops is one of the most important
sources of nitrogen (N). However, regarding the amount of N fixed, there are hardly
any published data for winter peas. Therefore, the N fixation of five regular leafed
winter peas types and one semi-leafless spring pea cultivar in single and mixed
cropping (with winter rye spring cereals respectively) was measured in four successive
growing seasons (2003/04 – 2006/07) at the experimental farm of the University of
Kassel and in two consecutive vegetation periods (2005/06 - 2006/07) at the
experimental farm of the University of Applied Science in Osnabrueck. The amount of
N fixed was calculated according to the extended difference method at the beginning
of flowering and at grain harvest.
N fixation was usually higher for winter peas than for spring pea. At the beginning of
flowering the amount of N fixed in pure stands was with a mean value of 92 kg ha-1 for
winter peas and 29 kg ha-1 for the spring pea higher than in mixture with a mean value
of 42 and 15 kg ha-1 respectively. At grain harvest the amount of N fixed for the spring
pea in pure stands was higher than in mixtures with a mean of 65 and 33 kg ha-1
respectively. On the other hand the N fixation for winter peas was usually comparable
in pure and mixed stands with a mean of 100 and 86 kg ha-1 respectively. This was a
consequence of the higher pea grain yield in mixture than in pure stands and of a
reduced biomass (leaves) loss in mixtures. Therefore, regular leaf winter peas can
contribute to the N supply of the crop rotation better than spring peas.