Íslenskar landbúnaðarrannsóknir - 01.03.1979, Page 51

ÍSL. LANDBÚN.
j. agr. res. icel. 1979 11, 1-2: 49-54
The inoculation of Lupinus Nootkatensis Donn. with
Rhizobium Lupini in Iceland
tjrUÐNi Harðarson and D. Gareth Jones
Department of Agricultural Botany, University College
of Wales, Aberystwyth, SY23 3DD.
ABSTRACT
The inoculation of Lupinus nootkatensis with strains of Rhizobium lupini was investigated in a laboratory
experiment at Aberystwyth and in field trials at Keldnaholt, Gunnarsholt and Skógarsandur in Iceland.
In the laboratory, strain 3211 from Rothamsted was significantly more eífective in nitrogen fixation than
the other inoculants. In the field trials, strain 3211 produced significantly more numbers ofnodules than the
other Rhizobium strains. This successful nodulation by 3211 was reflected in the higher yield oflupin plants
inoculated by this strain, in fact, nearly 3 times greater yield oflupin plants inoculated by this strain, in fact,
nearly 3 times greater yield compared with the uninoculated control. It seems therefore that the lack of
suitable Rhizobium bacteria in the soil is the main limiting factor for the successful cultivation of lupin in
Iceland.
The potential value of lupin as a pioneer crop in reclamation in Iceland is discussed.
INTRODUCTION
The loss of vegetation and soil is a serious
threat to Iceland’s natural environment.
1100 years ago at the beginning of sett-
lement, probably V2 to 3/s of the country
was covered with vegetation (Einarsson,
1962, 1963) compared with less than V4 of
the country now. Wind erosion is the main
cause of this loss, but volcanic activities
and overgrazing also add to this deterior-
ation. Despite considerable reclamation
in the last few decades, annual loss ofveg-
etation and soil still exceeds the area
which is regrown naturally or by man.
Various research projects are now be-
ing conducted to fmd out the carrying
capacity of the rangelands. (Thor-
steinsson. 1972). These projects have
mainly included classiíication and
mapping of the vegetation, as well as stu-
dies of the botanical composition, pro-
ductivity and nutritive value of the veget-
ation.
Preliminary study has shown that it is
possible to increase the carrying capacity
of the range lands 10-15 fold by fertilizing
and draining the soils (Thorsteinsson,
1972), but the increase in the cost of nit-
rogen fertilizers, between 1972 and 1974
has become the limiting factor for it’s use
on the range lands. An alternative to nit-
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