Fjölrit RALA - 15.12.2000, Page 22

20
Table 18. Total yield (grass + weed) in Iceland 1998, DM hkg/ha.
lst cut 2nd cut (4.8.) Total
(15.6.) Fertilized yield
Lavang 37.9 34.4 72.3
Fylking 33.7 43.5 77.2
Seida 43.8 32.5 76.3
Vega 37.6 27.5 65.1
Engmo 42.1 27.1 69.2
Leikvin 35.0 35.1 70.1
Leik 45.0 32.7 77.7
Unnur 42.9 44.6 87.5
Norcoast 39.2 36.7 75.9
SD 4.9 2.9
lst cut 2nd cut (6.8.) Total
(30.6.) Not fertilized yield
Lavang 57.4 9.1 66.5
Fylking 57.0 13.2 70.2
Seida 62.8 10.8 73.6
Vega 67.2 3.2 70.4
Engmo 66.6 4.8 71.4
Leikvin 59.0 7.7 66.7
Leik 65.8 5.9 71.7
Unnur 68.2 11.2 79.4
Norcoast 61.0 8.9 69.9
SD 7.1 2.2
Interactions - Locations and varieties. Table 19 shows the dry matter yield of each variety at
each location and on three different harvest dates (the first, the third and the fifth), an average
of all experiment years. The last harvest each year in these experiments was harvested with a
harvesting machine on relative large plots, while other yield observations were made by
clipping small strips. Because of this, only observations from the last harvest dates were
analyzed for interaction. Because of large differences between species the P. pratensis
varieties Lavang and Fylking were then compared separately, and Vega and Engmo
separately. An interesting question is whether these species and varieties have the same
ranking at all locations or whether there is an interaction between locations and varieties. If
no interaction between locations and varieties is found, it indicates that results from one
location can to some extent apply to the others.
The yield differences between Vega and Engmo were not statistically significant and
the interaction between locations and varieties was not significant either. On the other hand,
the year effect and the interaction between years and locations were significant. This rneans
that Vega and Engmo were very equal at all locations, but which of them was better, varied
with the year. This also indicates that to a certain extent results can be used interchangeably
The difference between Lavang and Fylking was not statistically significant at the last