Ársrit Ræktunarfélags Norðurlands - 01.01.1974, Blaðsíða 92

ing heat in the period june-augnst (r = 0,76**). Low precipitation in
early summer (july) sometimes has slowed down the yield considerably
such that heat and precipitation would together follow the yield even
better.
C. Fertilisation experiments suggest that there is no reason to
use more than 240 kg N and 115 kg P per hectare, but it is more
difficult to make suggestions as far as potassium fertilizer is concerned.
D. An experiment, in which shoots were cut off the seedling potatoes,
shows that if the shoots become few, especially less than three on each
potato, the yield decreases considerably.
E. It was also shown, that there was no advantage in having the
growth space in each row less than 25 cm, the rows being 60 cm apart
from each other. If the growth space become less, the ratio of market-
able potatos to those that were smaller, decreased quite considerably.
F. Using Afalon for chickweed eradication, 1 kg/ha appeared to be
sufficient in order to obtain maximum yield. Greater concentration
of the drug decreased the yield. Phalatability test showed that the drug
spraying diminshed the quality of the potatos, especially when a concen-
tration of 3—5 kg/ha was reached.
HEIMILDARRIT
Árni Jónsson. 1952. Kartöfluafbrigði og árferði 1949—1951. Ársrit Rækl-
unarfélags Norðurlands 1950—1951.
Bjarni Helgason. 1970. Áburðartilraunir við ræktun kartaflna. ísl. landbún.
Dept. of Agriculturi for Scotland. 1956. Seed Potatos. Edinburgh.
Hellbo, E. og Esbo M. 1942. Vára potatissorter. Stockholm.
Jahob Líndal. 1913. Kartöflutilraunir. Tíu ára yfirlit. Ársrit Ræktunarfé-
lags Norðurlands 1913.
Klapp, E. 1928. Studium iiber Deutsche Kartoffelsorten. Berlin.
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1928—1950. Rit Landbúnaðardeildar. B-flokkur. Nr. 4.
Lunden, A. P. 1956. Synonymer i poteavlen. Meld. fra NLH.
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Ræktunarfélags Norðurlands í 30 ár. Ársrit Ræktunarfélags Norðurlands 1933.
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raunum Ræktunarfélags Norðurlands i 45 ár. Ársrit Ræktunarfélags Norður-
lands 1948-1949.
Potetsorter i Norge. 1954. Eget forlag. Oslo.
Salaman, M. D. 1926. Potato varieties. Cambridge.
Schick, R. et. al. 1962. Die Kartoffel. Berlin.
Sturla Friðriksson. 1954. Samanburður á kartöfluafbrigðum 1948—1953. Rit
Landbúnaðardeildar. A-flokkur. Nr. 9.
Sortsliste for poteter. 1970. L. O. T. Oslo.
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