Íslenskar landbúnaðarrannsóknir - 01.03.1971, Síða 48

46 ÍSLENZKAR LANDBUNAÐARRANNSÓKNIR
SUMMARY
STUDIES ON THE GROWTH OF ICELANDIC FESTUCA RUBRA SSP.
RICHARDSONI AT DIFFERENT LEVELS OF pH IN THE SOIL.
Þorsteinn Tómasson
Agricultural Research Institute
Studies were undertaken in Aberdeen, Scotland, on a selection of 237 clones of
fescue (Festuca rubra ssp. richardsoni) originating from eleven different habitats
in Iceland.
The clones were replicated six times and grown in pots at two levels of fertility
and tbree levels of pH.
Differences in pH was achieved through the application oí sulphur (low pH)
and lime (high pH) and by leaving the soil untreated. Hydrated gypsum was add-
ed to all the pots to try to isolate the effects of pH from possible nutritional effects
of the sulphur and lime.
Tlie grass responded to the low pH treatment giving 7,2% increase in yield
over the other pH levels.
There was a significant, positive interaction between low pH and response
to nitrogen (table 1—2).
Differences in yield related to provenances (table 3) were found but ratio-
nalization of these residt is difficult due to lack of information pertaining to
differences between these provenances.
Damages due to acidity was observed in the low pH treatment after the harvest.
This damage was found to be significantly correlated to the habitat of origin
of the plants (table 4), there being less damages in plants from the richer types of
soils.
It is felt that these results particularely open the question of the role jdayecl
by edaphic factors, especially calcium, in the formation of ecotypes in the
country.
Research to reveal edaphic preferences of grasses, both of exogenous and indi-
genous origin is called for especially with reference to the permanent nature of
pastures in the country.