2. Plant height mean. The interactions of clover and vetch green manures with 100% of recommended nitrogen had the
greatest effect on plant height and they increased plant height by 17.6 and 17.4 %, respectively; in comparison with
control and among other treatments that they had significant difference with control, clover and vetch treatments
with 75% of nitrogen and canola with 100 % of recommended nitrogen were the top treatments and they increased
14
plant height mean by 13.8, 13.6 and11.9%, respectively; in comparison with control (Fig. 2). According to the
characteristics of legume plants about nitrogen production, the use of these plants as green manure increase growth
and height of potato plants.