Ársrit Ræktunarfélags Norðurlands - 01.01.1966, Síða 43

45
Fyrra ár tilraunarinnar var uppskeran mest á lið sem fékk
122 kg/ha P, en síðara árið á lið sem fékk 92 kg/ha P auk
búfjáráburðar.
Þakkarorð.
Höfundum ritgerðarinnar er bæði ljúft og skylt að þakka
öllum þeim, sem lagt hafa grundvöllinn að ritgerðinni með
starfi sínu við tilraunirnar. Mestan hlut hafa þar átt þau
Hanna Frímannsdóttir, F.ygló Gísladóttir, Ragna Hróbjarts-
dóttir, Jón Snæbjörnsson, Magnús Ellertsson, Ottar Geirs-
son og Hólmgeir Björnsson. Sementsverksmiðja ríkisins á
þakkir skyldar fyrir fjárhagslegan stuðning. Einnig þökkum
við Bændaskólanum á Hvanneyri og skólastjóra hans, Guð-
mundi Jónssyni fyrir veitta starfsaðstöðu.
Summary.
The experimental site was a peat soil at Hvanneyri, located 64° 34'
northern latitude and 21° 40' western longitude.
The experiments were concerned with the application of phosphorus
fertilizer at establishment of a permanent grass field:
A. Methods phosphorus application.
B. Phosphorus fertilizer and cow manure.
In one of the experiments liming and grasing were combined with
methods of phosphorus application.
Triple superphosphate (19.7% P) was used as phosphorus fertilizer.
Without P-fertilizer application no growth of grasses occurs on the
peat soil at Hvanneyri after drainage. tillage and sowing.
Heavy application of P-fertilizer (153—350 kg/ha P) without a fol
lowing yearly application resulted in a decrease in P-percentage of the
grasses, throughout the years.
Higher yields were achieved by yearly application of 31 kg/ha P for
five years, than by a application of 153 kg/ha P at establishment of
the grass field without following yearly application.
The experiments indicate that by early sowing rotatilling of the P-
fertilizer (153—350 kg/ha P) to 20 cm depth may cause higher yields
than surface broadcasting of the same amount. Especially may the rota-
tilling of the P-fertilizer cause a yield increase if the heavy application
is followed by yearly P-application.
Grasing, liming and method of P-application affected the botanical