Íslenskar landbúnaðarrannsóknir - 01.03.1979, Page 53

THE INOCULATION OF LUPINUS 51
Table 2.
Symbiotic characteristics of the Rhizobium strains.
Strain Dry weight/plant (mg) Nodule No/plant Nodule score/plant
3211 72 9.4 26.6
3210 43.3 D* 0,05 = 20.9 8.1 D 0.05 = 4.5 21.6 D 0.05 = 11.3
90 34.3 10.9 24.2
no inoculation 37 2 D 0.01 = 25.8 0.1 D 0.01 = 5.5 0.4 D 0.01 = 13.8
D* = significant difference calculated from „Q“ in the Studentized range.
1. Inoculant from Iceland (populat-
ion size unknown)
2. Inoculant from Rothamsted (St-
rain 3211, peat culture, ca. 108
bacteria/g)
3. Inoculant from Ultuna, Sweden
(Three strains of R. lupini, popul-
ation size unknown)
C) Inoculant applied 5 weeks after
sowing.
1—3. Inoculation treatments as in B.
In the field trials only the most eífective
strain from Rothamsted (3211) was used.
Strain 90 had previously been found to be
ineffective in nitrogen fixation and it was
therefore excluded from the field trials and
another inoculant from Iceland of un-
known effectiveness used instead. The in-
oculant from Ultuna was also included
without förmer study of its effectiveness.
All seeds were scarified, which increas-
ed the germination up to 90%. The plot
size was 2 X 2 m and each treatment was
replicated 3 times in a randomized block
design. The experiments were sown on the
7-9th ofjune and harvested on the 14—15
of September, 1977, when the dry weight
of 10 plants from each plot was measured
and the numbers of nodules counted.
RESULTS
Symbiotic characteristics of three strains of R.
lupini
The symbiotic characteristics of the Rhizobi-
um strains 3211, 3210 and 90 were com-
pared on lupin and the results are sum-
marized in Table 2. There were highly
significant differences in yield between the
Rhizobium strains (P<0.001) with 3211
being far more effective in nitrogen fixat-
ion than the other strains and 90 being
totally ineffective although it nodulated
the plants efficiently. The Rhizobium stra-
ins also resulted in significantly different
nodule numbers being produced and the
nodule scores were also significantly dif-
ferent between treatments (P<0.001).
Results from lupin inoculation field trials in
Iceland
The trials were conducted on five different
sites in Iceland. Wind erosion destroyed
two trials in the highlands at Búrfell and
Sigalda, so only three trials were harvest-
ed.
The numbers of nodules on the lupin
plants in the experimental plots are sum-
marized in Table 3. There were highly
significant differences between inoculat-
ion treatments (P<0.001) with 3211 being
the most successful in producing nodules.