Ársrit Ræktunarfélags Norðurlands - 01.01.1966, Blaðsíða 44

4(5
composition of the grassfield in the first years after establishment.
Grasing caused a very pronounced decrease in the proportions of
meadow foxtail (Alopecurus pratenis), timothy (Phleum pratense) and
red t'escue (Festuca rubra), but increased the proportion of Poa and
Agrostis.
Liming (4 tons/ha, lime) increased the proportions of meadow fox-
tail, timothy and Poa, but decreased the proportions of Agrostis.
Rotatilfing of the phosphorus fertilizer (153 kg/ha P) to 20 cm depth
as compared to surface broadcasting caused an increase in the propor-
tions of Agrostis and decrease of Poa.
Grasing resulted in a very considerable thinning out of plants in
the sward.
fncreasing amounts of triple-superphosphate at establishment of a
permanent gras field were tried as supplement to cow feces f40 tons/ha
corresponding to ca. 140 kg/ha P. The manure and the phosphate were
rotatilled to 20 cm depth.
fn the year of establishment the maximal yield was reached by 122
kg/ha P, 13.3 hkg/ha hay more than the yield of the cow manure alone.
fn the second year the corresponding figures were 92 kg/ha P and 2.8
hkg/ha hay.
Heimildir.
Magnús Oskarsson og Þorsteinn Þorsteinsson (1964): Áhrií
kalks, kalkssaltpéturs og Kjarna á efnamagn og sprettu
grasa. (F.ffect of Lime, Calcium Nitrate and Ammonium
Nitrate on Mineral Content and Growth of Grass): Árs-
rit Ræktunarfélags Norðurlands, Akureyri, 1964.
Ottar Geirsson (1963): Áhrif áburðar og sláttutíma á upp-
skeru og efnamagn nokkurra grastegunda. Ársrit Ræktun-
arfélags Norðurlands (1963).
Steenbjerg, F. (1965): Lærebog i planternes ernæring. DLS-
Forlag, Köhenhavn 1965.
Franck O. (1950): Aktuelt ifrága om fosfatgödsling. Váxt-
nárings-Nytt, 4: 1—8.