CONCLUSION
According to the results of the combined analysis of all traits measured in the terms of the separate effects of green
manures and nitrogen were highly significant. Interaction of factors tested in the first three traits at 1% and in the terms
of potato tuber yield at 5 % level were significance. Comparison of the in teraction of green manure and nitrogen showed
that the interaction of clover green manure with 100% of recommended nitrogen had the most effect on the number of
stems per plant in comparison with control and it increased stem number per plant by 21.8 %. In the terms of height per
potato plant, the interaction of clover and vetch green manures with 100 % of recommended nitrogen had the most effect
on plant height and increased plant height mean by 17.6 and 17.4%, respectively; in comparison with the control. In the
terms of the interaction of experimental factors on stolon number, clover green manure with 100 % of recommended
nitrogen was the best treatment and increased number of stolon per potato plant by 38 % in comparison with the control
and finally in the terms of tuber yield per unit area, the interaction of clover green manure with 75% of recommended
nitrogen was the best treatment and it had significant difference at 1 % with the control and it increased tuber yield by
33%. In addition, it decreased the amount of nitrogen consumption by 25%. According to results of this research,
generally, the effect of experiment green manures include clover, vetch, canola and barley on number of stem and
height of each potato plant were significant and among them, legume green manures of clover and vetch is the best
treatments for increasing of stems growth. Also, clover and vetch treatments increased stolon number per plant and
potato tuber yield, significantly. Thus, it could be concluded that legumes green manures were the best treatments. On
the other hand, the above mentioned characters are severely affected by N fertilizer. The effect of 100 and 75 percent of
recommended nitrogen on tuber yield was the same statistically. The best compound of treatments on tuber yield was
clover green manure with 75 % of recommended N since this treatment compound increased tuber yield by 33 %, where
as reduced N demand by 25%.