Two experiment were carried out during the two growing seasons of 2010 /2011 and 2011 /2012 to study the effect of plant density of faba bean intercropped on wheat and nitrogen fertilization on yield and its components for both crops. A split plots design with three replications was used. The main plots were devoted to nitrogen fertilizer levels (60, 75 and 90 kg N/fad. Whereas, the sub plots were allocated for pattern systems P 1 ,P 2 ,P 3 (100 wheat 12.5%, 25% and 37.5% faba bean

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... The results indicated that increased population of faba bean from 12.5 % to 37.5 of solid led to reduction for all study characters number of spikes/m 2 , grain/ spike, weight of grains spike and 1000 grain, grain and straw yield/ fad of wheat in the combined data. The reduction in grain and straw yield of wheat were estimated 5.84 and 6.47 for P 1 , 10.09 and 8.82% for P 2 13.33 and 13.53% for P 3 respectively. Intercropping 100% of wheat with faba bean (P 1 ) recorded the highest values of most yield components of faba bean, while the lowest values were observed by third density (P 3 ). Seed and straw yield were increased by increased plant density of faba bean (P 1 toP 3 ) but reduced as compared with solid yield. This in seed and straw yieldfaba bean were 75.57 and 76.24 for (P 1 ) 61.48 and 66.70 for (P 2 ) 47.60 and 55.55 for (P 3 ) respectively.Grain and seed yield of wheat with faba bean were significantly affect by nitrogen fertilizer levels. The highest values of both crops (95.24 and 48.75) were observed when added 90 kg N/fad. While the lowest values (85.63 and 29.33) with 60 kg N/fad of solid crops. The highest of LER (1.53) MAI (4574.73) and MER (1.42) were observed (N 3 ×P 3 ) while the lowest was observed (N 1 ×P 1 ). The values ofaggressivity (Ag) for faba bean was positive while wheat was negative it means that faba bean was dominated while wheat was dominated. 31 El-Monufi (1984) stated that intercropping wheat with faba bean decreased straw and grain yields of wheat/faddan, as well as plant height, branches and pod number/plant, straw and seed yield/faddan of faba bean. On theother hand plant height and 100-grain weight of wheat, as well as 100-seed weight, harvest index and productivity score of field bean were lower than sole planting. Many investigators found that the land use efficiency was increased and yield advantage was produced by intercropping fababeanasalegume crop with non legume crops such as wheat ( Saleh et al 1986 and Abd-El-Gawad 1988) fodder beet (El-Kassaby et al, 1985 and Abdel-Aal et al 1989) and barley Abo-Shetaia 1990. reported that the yields of fababean and barley per faddanwere varied with1:1, 1: 2, 2:2 and 3:3 intercropping patterns. Pattern 3:3 produced the highest yield advantage for each crop which amounted to 60% more than the sole cropping. Abdel-Shafie et al (1986) and Radwan (1993) showed that spike length, number of spikes/m 2 , number grains/spike, grains weight/spike, weight of1000 grain of wheat were increased by intercropping with faba bean, while grain and straw yield/fad. werereduced compared with culture. El-Naggar et al (1991) showed that plant height, tiller numbers and 1000 grain weight of wheat were increased when intercropped with berseem.Willey and Osiru (1972)stated that yield of each component of both cropswill depend on both interspecific and intraspecific competition. Therefore, it is necessary to test a wide range of densities of each component in a wide range of combinations.(Allen and Obura 1983) interspecific facilitation occurs when one plant species enhances thegrowth of another plant species and has been observed mainly in legume/cereal systems such as soybean/corn and cowpea/corn. Saleh et al (1986) found that intercropping legume with wheat in 2:2 intercropping system significantly increased plant height number of spikes/m 2 and grain yield/fad. of wheat than monoculture and the other two intercropping system (3:3 and 4:4). Monoculture in faba bean produced highest number of pods and seeds/plant as compared with the intercropping system. On the other hand, growing wheat and fababean in 2:2 intercropping system produced yield advantage and increased land usage by about 90 followed by 3:3 and 4:4 systems (about 80%). Wheat was the dominant intercrop component under the different systems. Mahrous et al (1998) found that intercropping lentil with wheat decreased grain or seed and straw yield, seed index for crops, number of grains/spike for wheat and number of branches for lentil. Eid et al (1988) found that intercropping wheat with faba bean 1:1 pattern gave the maximum values of LER and relative crowding coefficient (Rcc). El-Mihi et al (1991) found that competitive relationships of wheat-faba bean revealed that in mixture (2:2), land use efficiency was rather less than other intercropping systems mainly due to a higher aggressivity pressure.Khaliq et al (2001) found that in termsof monetary grain, the highest net income was obtained from intercropping one row of lentil with two rows of wheat.Liben et al (2001) reveledalso highest land equivalent ratio (LER) and yield advantage with highest anet return were observed when1 maize: 1 faba bean pattern was applied. Nitrogen is the most important plant nutrient needed to obtain high yield. El-Naggar and El-Habbak (1991) reported that plant height, number of branches and pods/plant number of pods/ plant, 100 seeds weight, as well as EFFECT OF PLANT DENSITY OF FABA BEAN INTERCROPPED... Fayoum J.