Rit Landbúnaðardeildar : B-flokkur - 01.05.1957, Side 101

99
Exþeriment No. 19 deals with a comparison between two separate varieties of
grass-seed mixtures, sown with and without oat-seed as shelter (Table XXIII). The
shelter-seed seems to reduce the yield a little in the year immediately following the
seeding, but the effects are not permanent. There is no real difference between the
grass-seed mixtures.
Experiment No. 20 deals with the seeding of wliite clover in cultivated grassland
(Table XXIV). The seeding was tolerably successful, and there was a distinct increase
in the yield of hay because of the clover, although it was less than it might have been,
if harvesting of tlie first crop had taken place earlier.
Experiment No. 21 deals with increasing seeding quantities of white clover (Table
XXV). The clover has not produced any overall increase in yield in this experiment.
Its effect seems to have been on the increase in the last two years, but as a rule the
harvesting is carried out too late.
Experiment No. 22 deals witli two parallel experiments with different seeding
quantities of grass-seed mixture, and a grass-seed mixture containing 40 per cent. of
white clover. The quantities involved were 20, 30 and 40 kg respectively per hectare
(Tables XXVI and XXVII). From the experiments no advantage can be deduced of
the use oí more than 20 kg of grass-seed or grass-seed+clover per hectare.
The error for most of the above experiments has been worked out and has on the
whole proved to be insignificant. In the working-out of the error, the Fisher method
has been followed. Quantities of fertilizers are usually measured in kg, whereas farm-
yard manure is often given in tons per hectare. Yield is almost invariably given in
hkg per hectare.
List of words of frequent occurrence in tables, etc.
Áburður = manure, fertilizer;
Áburðartími = fertilizing period;
Ár = year;
Búfjáráburður (hrossatað, kúamykja, haugur) = farmyard manure;
Frávik alls = sum of squares;
Frítala = degrees of freedom;
gras = grass;
Háar % = percentage of second crop;
Hey = hay;
Hey % = percentage of hay;
Hlutföll = proportions;
s
V n
m/m = zfc Vmj + m’
Meðalfrávik = mean square;
Meðaltal = average;
Samtals = total;
1. sláttur (slegið í 1. sinn) = first crop;
2. sláttur (slegið í 2. sinn) = second crop;
Tilbúinn áburður = fertilizer;
Þurrt = dry hay.
I
>