Two filed experiments were carried out at Nubaria Agric .Res
Station during 1998 and 1999 seasons to study the effect of plant spacing of
sunflower i . e .20 anc 30 cm between h:lls and three nitrogen fertilizer levels i
. e .45,60 and 75kg N/fed on yield and competitive relations of sunflower and
soybean . A split plot design with three replications was used. The main
results could be summarized as follows. The two plants spacing of sunflower
occupied the main plots in both solid stand and intercropping planting. The
nitrogen fertilizer levels were arranged in sub plots in both solid and
intercropping treatments. The results indicated that plant spacing of sunflower had a
significant effect on seed yield of soybean plants, seed Yield of sunflower,
land equivalent ratio and aggressivity in the two seasons. Increasing plant
spacing of sunflower significantly decreased seed yield of sunflower. The
spacing of 20 cm gave highest seed yield of sunflower comp~re to hill spacing
of 30 cm. Nitrogen fertilizer levels were significant effect on seed yield of
soybean in the two seasons and aggressivity only in the second season
.Increasing nitrogen fertilizer levels significantly increased seed yields of
soybean Maximum seed yield I feddan of soybean was ob ained by adding
60 kg N/fed. All interactions did not show any significant effect on all studied
characters. It could be concluded that increasing plant spacing of sunflower to
30 cm between hills increased LER value and more than one, sunflower was
dominant crops. whereas soybean was dominated