Íslenskar landbúnaðarrannsóknir - 01.09.1980, Side 12

10 ÍSLENZKAR LANDBÚNAÐARRANNSÓKNIR
SUMMARY
The rangeland research program in Iceland.
Ingvi Þorsteinsson.
Agricultural Research Institute
Keldnaholt, Reykjavík.
The importance of natural rangelands for
the world food production is stressed. In
Iceland nearly half of the roughage con-
sumed annually by the livestock is pro-
vided by such land. In earlier times winter
grazing caused most harm to the vegeta-
tion bút owing to steadily increasing area
and areal production of cultivated pastu-
res, winter feed is no longer a limiting
factor in the livestock production. In
many parts of the country, especially the
highlands, overgrazing of the summer
rangelands is common. Hazardous and
improper use of the vegetation through
the centuries is considered to be one of the
main reasons for its catastrophic deteri-
oration and for the extent of soil erosion in
the country.
In 1955 a research program was initia-
HEIMILDIR - REFERENCES:
Björn Sigurbjörnsson, 1979. Landbúnaðariramleiðsla
og náttúruvernd. Erindi flutt á XI. þingi NJF í
Osló. Sérprentun.
Björn Jóhannesson og Ingvi Þorsteinsson, 1957. Gróð-
ted by the Agricultural Research Institute
in Iceland with the purpose of determi-
ning the carrying capacity of the range-
lands and securing proper stocking rate.
The program covers the following main
fields of study: 1) classification of the
vegetation, 2) vegetation mapping, 3)
measurements of the botanical compo-
sition and annual production of plant
communities, 4) studies of growth condi-
tions, 5) studies of the plant preference of
sheep, 6) determination of the nutritive
value of the diet, 7) studies on the effects of
different grazing pressure on vegetation
and on the performance of the livestock, 8)
studies on the nutrient requirements of the
livestock, 9) areal measurements from the
vegetation maps and calculations of the
carrying capacity based on data from the
listed studies.
In the following chapters each of these
studies is discussed and examples are
given showing the results ofcalculations of
carrying capacity of a highland range and
of a lowland farm.
urkort og lýsing Gnúpverjaafréttar. Rit Land-
búnaðardeildar.
Webber, P. F. 1974. Primary productivity in arctic
and alpine environment. 445-473. Methuen and
Co. Ltd.