Ársrit Ræktunarfélags Norðurlands - 01.01.1967, Side 97

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3. G. ap Griffith og R. J. K. Walters (1966): The sodium and potass-
ium content of some grass genera, species and varieties. The Journal
of Agricultural Science, Vol. 67, bls. 81—89.
4. Þorsteinn Þorsteinsson og Magnús Óskarsson (1963): Áhrif, kalíum,
magníum og kalsíum í áburði á uppskeru og steinefnamagn grasa.
Árbók landbúnaðarins, nr. 4.
5. Þorsteinn Þorsteinsson, Magnús Óskarsson og Viðar Kornerup-
Hansen (1964): Steinefni í fóðri búfjár. Búnaðarritið LXXVII.
árg.
6. O. Johansson (1964): Balanserad váxtnáringstillgáng. Váxt-Nárings-
Nytt, 20. árg. bls. 3:1—3:11.
7. Herbage Abstracts (1966), 36. árg. nr. 2155.
8. Ingvi Þorsteinsson og Björn Sigurbjörnsson (1961): Áburðarathug-
anir á Biskupstungnaafrétti. Árbók landbúnaðarins, XII. árg. bls.
28-46.
9. Sturla Friðriksson (1963): Gróðurfarsbreytingar á framræstri mýri
á Hjarðarfelli í Miklaholtshreppi. Freyr, I.IX. árg. bls. 212—216.
Summary.
Experiments were made concering the iníluence of nitrogen, potas-
sium and phosphorus fertilizers on wet fields grown with carex and
grasses. In Iceland such fields have been used for haymaking for cen-
turys, but fertilizer has not been applied. The experiments were locat-
ed at the agricultural school of Hvanneyri in West-Iceland and the
agricultural experimental station at Skriuklaustur in East-Iceland. At
Hvanneyri observations were made on the germintion of seed of the
carex Lyngbyei.
At both stations nitrogen and phosphorous had a positive effect on
the hay yield but potassium had neglegible effects. The hay yield was
far greater at Hvanneyri than Skriuklaustur.
At both places the carexes decreased in number and the grasses
increased by the use of fertilizers. At Hvanneyri calamagrostis neg-
lécta was the prevailing plant, but carex Lyngbyei and agorstis stoloni-
fera were there to some extent.
Carex Lynbyei has a high potential for increased sodium content
which calamgrostis neglécta, agrostis stolonifera and poa pratenses
have not. Sodium contents is increased by applied nitrogen and phos-
phorous.
The phosphorous content of the plants was very low both at Hvann-
eyri and Skriðuklaustur were no phosphorus fertilizer was applied.
The phosphorous content of carex Lyngbyei was also very low where
phosphorous fertilizer was applied.