Íslenskar landbúnaðarrannsóknir - 01.09.1975, Page 21

BREYTINGAR Á JARÐVBGI 19
Ammonium nitrate has sofar only caused
detectabie leaching at Sámsstaðir, where
there is heaviest precipitation.
At the four soil depths investigated K+ is
slightly reduced by all three fertilizers, of
which ammonium nitrate seems to have the
HEIMILDARRIT — REFERENCES
Abruna, F., Pearson, R. W. og Elkins, C. B. 1958:
Quantitative Evaluation of Soil Reaction and
Base Status Changes Resulting from Field App-
lication of Residually Acid- Forming Nitrogen
Fertilizer. Soil Sci. Soc. Am. Proc., 22: 539—
542.
Coleman, N. J., Kamprath, E. J. og Weed, S. B.
1958: Liming. Advances in Agronomy, 10:
475, 522 (499. bls.) útg. Academic Press.
Bjarni Helgason 1959: A Study of Some Soils in
South-western Iceland. Ph.D.-ritgerð. Háskólinn
í Aberdeen.
Bjarni Helgason 1968: Basaltic Soils of South-
West Iceland. II. Journ. Soil Sci., 19: 127—
134.
Jackson, W. A. 19'67: Physiological Effects of
Soil Acidity and Liming, 43—124 (57. bls.)
útg. American Society of Agronomy.
strongest influence, especially in the 0—5
cm layer (Tables III & III A).
The use of ammonium sulphate has led to
some increase in the organic matter content
of the 0—5 cm layer (Table IV & V).
Björn Jóhannesson 1960: Um sýrustig íslenzks
jarðvegs og áhrif áburðar og áburðarkalks á
sýrustig og uppskeru. Freyr, 56: 197—204.
Arni Jónsson 1955: Skýrslur tilraunastöðvanna
1953—-1954. Rit Búnaðardeildar, A-flokkur.
nr. 11.
Nafnlaus 1973: Skýrsla jarðræktardeildar 3, 94.
bls. útg. Rannsóknastofnun landbúnaðarins.
Nafnlaus 1967: Súr og basísk áhrif köfnunar-
efnisáburðar. Handbók bænda, 17: 154—155.
Warren, R. G. og Johnston, A. E. 1964 (1963):
The Park Grass Experiment. Rothamstead Exp.
Sta. Rep. 240—262.
Þorsteinn Þorsteinsson og Magnús Oskarsson
1960: Áhrif Kjarna á sýrustig jarðvegs. Freyr,
56: 205—207.