Íslenskar landbúnaðarrannsóknir - 01.09.1970, Blaðsíða 68

66 ÍSLENZKAR LANDBIJNAÐARRANNSÓKNIR
Pottatilraunir þær, sem hér hefur verið
rætt um, og erlend tilraunareynsla, sem
vitnað er í, virðast benda í þá átt, að al-
hliða næring, sem tryggir góðan vöxt, sé
jafnframt sú næring, sem tryggir sömu
plöntur bezt gegn kali. Hitt er svo annað
mál, sem þessar tilraunir gefa ekki tilefni
til að ræða, hvort sama næring henti tveim-
ur plöntutegundum og hver áhrif samspil
áburðar og grastegunda hafi í túnræktinni
gagnvart kali.
ÞAKKARORÐ
Öllum þeim, sem á einn eða annan hátt
stuðluðu að framkvæmd tilraunanna, eru
færðar þakkir, en sérstaklega þeim Ólafi
Birni Hallgrímssyni og Þorvaldi Friðriks-
syni, sem unnu að daglegri framkvæmd til-
raunanna, og Einari Erlendssyni, umsjón-
armanni tilrauna á Korpu, fyrir margvís-
lega fyrirgreiðslu.
S U M M A R Y
FEliTILIZEli APPLICA TION AND WINTER HARDINESS
OF PHLEUM PRATENSE
Friðrik Pálrnason,
Agricultural Research Institute, Reykjavik, Iceland
In the year 1968 pot experiments were started in which a compound fertilizer
of the grade 22-6-9 (N-P-K) i.g. 22-11-11 (N-P205-K20) was compared to ammo-
niumnitrate, triple superphosphate and potassium chloride. Treatment with po-
tassium sulphate were included because of the sulphur content of the compound
fertilizer, 2.7% S. The soil used was a peat soil from Korpúlfsstadir in the
neighbourhood of Reykjavík, SW-Iceland. And the experiment was carried out
on the same place.
The experiments were 6, but exp. no. 1 and 2 were performed as one experi-
ment.
(1—2) Increasing amounts of nitrogen at two levels of potassium 50 and 75
kg/ha K. The nitrogen was given in ammoniumnitrate and in the com-
pound fertilizer 22-6-9 (N-P-K).
(3) Increasing amounts of phosphorous in triple superphosphate and in
the compound fertilizer 22-6-9 (N-P-K).
(4) Increasing levels of potassium in potassium chloride, potassium sul-
phate and in the compound fertilizer 22-6-9.
(5) Increasing levels of N-P-K in the ratio 1 : 0.22 : 0.42. The fertilizer
compared were ammoniumnitrate -þ triple superphosphate -j- po-
tassium chloride and the compound fertilizer 22-6-9.
(6) Increasing amounts of nitrogen with basic treatment of potassium
sulphate and potassium chloride respectively. Nitrogen applied in
ammoniumnitrate and in 22-6-9 was compared.
The treatments and tlie results are clscribed in the graphs 1—7 and in the
tables 1—6.