Íslenskar landbúnaðarrannsóknir - 01.09.1977, Qupperneq 41

ÍSL. LANDBÚN.
J. AGR. RES. ICEL. 1977 9, 2.' 39-46
The Inoculation of White Glover (Trifolium Repens h)
with Rhizobium Trifolii in Iceland
Guðni Harðarson
and
D. Gareth Jones
Department of Ag/icultural Botany,
Univershty College of Wales, Aberystwyth
Dyfed, Wales, U.K.
ABSTRACT
Strains of Rhizobium trifolii were screened for their effectiveness at low temperature in symbiosis
with white clover (Trifolium repens L.). Strains from Iceland and Sweden were found to be better
adapted for nitrogen fixation at low temperature compared with strains from the United Kingdom.
The present investigation also reports on a white dower-Rhizobium inoculation field trial in Iceland
using bacterial strains selected from those used in the screening trials. Indigenous bacteria were found
to be in a low number in the experimental plots and the results show the importance of inoculation
with Rhizobium bacteria. Lime pelleting and lime spreading was not found to affect yield or nodu-
lation significantly. Neither of the white clover varieties, Aberystwyth S184 and Pajbjerg smalbla-
det, used in this trial survived the first winter in Iceland. The results are discussed from the point of
view of improving the white clover-Rhizobium symbiosis at low temperature.
INTRODUCTION
The value of leguminous crops both for
their own yield of protein and for their
contribution to the nitrogen economy has
Iong been recognized. In Iceland, legumes
are very few and, of those present, white
clover is the most abundant and offers the
greatest agricultural potential. According to
Steindórsson (1962) white clover has a
rather odd distribution, being present in most
parts of the country except the north west
peninsula. However, even in districts where
it is present there are gaps in its distribution
where there are no apparent obstacles to its
spread although there is an extremely poor
seedset in the growing plants.
Although Jónsson (1939) was able to show
that many agriculturally important legumes
are able to grow and produce satisfactory
yields in Iceland no real emphasis has been
placed on white clover as an important