الفهرس 
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Abstract
Two field experiments were conducted at Zarzoora Agric. Experimental Station at EL-Behaira governorate in 1998 / 1999 and 1999 /2000 seasons to evaluate four intercropping patterns of three faba bean varieties with onion.
Intercropping patterns included :
1-Growing faba bean on the top of the ridge and onion on both sides of the same ridge, (0-F-0). This pattern denotes a 1: 2, faba bean: onion row intercropping system with 70000 faba bean + 200000 onion plants / fad .
2-Growing onion on the top of the ridge and faba bean on both sides of the same ridge (F-0-F), making a 2: 1 faba bean : onion row intercropping system with 140000 faba bean + 100000 onion plants / fad.
3-Growing onion on the top and one side of the ridge, while faba bean on the other side, (0-0-F), making a 1: 2 faba bean : onion row intercropping system with 70000 faba bean + 200000 onion plants/fad.
4-Growing faba bean on the top and one side of the ridge, while onion on the other side (0-F-F), making a 2: 1 faba bean : onion row intercropping system with 140000 faba bean + 100000 onion plants / fad.
In addition, onion in pure stand (200000 plants / fad) and faba bean sole cropping (140000 plants / fad ) were grown as a check treatments. The three faba bean varieties were: Giza 461,5-Number of branches / plant of the faba bean varieties did not differ significantly, while diameter of main stem showed significant differences in the second season where Giza 716 was of lower diameter than the other 2 varieties.
6-Average weight of faba bean plant at harvest significantly varied in both seasons. Giza 461 recorded the greatest weight in the first season (58.4g). In the second season, Giza 461 and Giza 716 recorded about the same weight (57.0g) and significantly surpassed Giza 843 (50.6 g).
7-Number of seeds / pod was the highest in Giza 716 variety in both seasons, being 3.73 and 3.60 in the first and second season, respectively. On the other hand, weight of pods / plant showed no significant differences in both seasons.
8-Weight of seeds / plant was the highest with Giza 716, being 32.4 and 32.3 g in the first and second season, respectively, with significant differences in the first season.
9-Seed yield / fad of Giza843 variety significantly surpassed Giza 716 and Giza 461 by 2.73 and 13.77% in the first season, corresponding to 1.36 and 9.43% in the second one, respectively.
10-Seed index of faba bean significantly varied in both seasons, Giza 461 was significantly inferior with an average of 76.35 and 74.1 g in the first and second season, respectively. Giza 843 recorded the highest 100-seed weight, being 86.80 and 84.40 g in the two successive seasons. Giza 716 recorded higher values than Giza 461, with an averageseed index of 86.2() and 84.3 g in 1998/99 and 1999/2000, respectively.
11-The three tested varieties showed significant differences in protein yield/ fad in the second season where Giza 843 significantly surpassed both Giza 716 and Giza 461 by 2.88 and 8.24% in the second season, respectively. On the other hand, N%, K% and protein % in faba bean seeds showed no significant differences among the 3 varieties.
12-P% in Giza 461 variety significantly surpassed that in the two other varieties, while P% in seeds of Giza 716 variety was inferior and P% in Giza 843 was inbetween.
II- Intercropping pattern effects:
1-Diameter, fresh weight and dry weight of onion bulbs at harvest were significantly reduced due to intercropping compared with sole cropping. Intercropping at lower onion densities (F-O-F and 0-F-F) led to serious reductions in bulb characters. Intercropping pattern (0-F-F) reduced diameter ,fresh weight and dry weight of bulbs by 73.21, 88.47 and 76.22%, respectively in 1998/99, being 75.41, 89.53 and 78.77% in 1999/2000, season compared with sole cropping.
2-Bulb yield was greatly reduced due to intercropping and the greatest reduction was recorded in (F-0-F) and (0-F-F) patterns. Bulb yield / fad was reduced in (F-0-F) pattern by 97.0 and 97.7%, compared with sole cropping in the first and second season, respectively.3-Neither protein % nor N% in bulb were significantly affected by intercropping. Protein yield of all intercropping patterns was drastically reduced, particularly with (F-0-F) and (0-F-F) patterns. Protein yield / fad was reduced by 96.7 and 97.4%, compared with sole cropping in 1998/99 and 1999/2000 season, respectively.
4-P% was also affected by intercropping and the highest P content reached 0.25 and 0.26% in (0-F-F) pattern in the first and second season, respectively, compared with 0.18 and 0.19% for the pure stand treatment. Also, K% significantly reduced by intercropping, reaching its minimum content of 2.29 respectively for (0-0-F)pattern, compared with 2.69 and 2.75% solid onion.
5-Plant height, number of branches / plant and diameter of main stem of faba bean were significantly affected by intercropping patterns. The tallest plants were those of solid planting and the shortest plants were produced by (0-F-0) pattern. The greatest number of branches were produced by (0-F-0) pattern and the lowest number was of the pure stand plants.
6-Plant weight, number of pods / plant, number of seeds / pod, weight of pods / plant, weight of seeds / plant, seed yield fad and 100-seed weight were significantly affected by intercropping patterns. The highest plant weight was observed with (0-F-0) system in both seasons and the lowest weight was recorded by (F-O-F) treatment. The highest number of pods / plant was obtained by (0-0-F) pattern inboth seasons and the lowest pods number was of (F-0-F) pattern in the first season and the pure stand in the second one.
7-Seed yield / fad was higher in some intercropping treatments than the pure stand yield. In (0-F-F) as well as (F-0-F) patterns seed yield / fad surpassed that of solid planting by 6.31 and 5.68%, in the first season, respectively, corresponding to 6.21 and 3.02% in the second season.
8-Chemical contents in faba bean seeds were significantly affected by intercropping patterns. Protein % was affected in the first season and (0-0-F) treatment recorded the highest value (29.88%). Protein yield recorded maximum value (587.98 and 569.36 kg in the first and second season, respectively) with (F-0-F) pattern.
9-N% in seed was the highest with (0-0-F) system in both seasons. P% was significantly affected in the first season, the highest content (0.66%) was recorded by (0-F-0) pattern.
10-K% was significantly affected by intercropping in both seasons. The highest K% was 0.85% in faba bean seeds in both seasons which was recorded by (0-0-F) pattern.
III- Interaction Effects:
1- Bulb fresh weight of intercropped onion was significantly affected by the interaction between faba bean varieties and intercropping patterns in the second season. The lowest value (7.1 g) was recorded by (0-F-F) system + Giza 461 variety. The highest fresh weight was of sole cropping. Also, bulb dryweight was affected by the interaction in both seasons and the lowest weight was 1.30 g in the first season which was recorded by (0-F-F) with Giza 461 and (F-0-F) with Giza 843. In the second season, (0-F-F) pattern recorded the lowest dry weight (1.33 g) with Giza 716 variety.
2-Bulb yield / fad was not significantly affected by patterns x varieties interaction in both seasons. Also, chemical contents in onion bulbs were not affected by the interaction.
3-Plant height of faba bean was affected by the interaction in both seasons. The tallest plants were produced by Giza 461 sole cropping (162.0 cm) in the first season, and Giza 843 variety + (0-F-F) pattern in the second season (157.0 cm). Number of branches / plant and diameter of main stem were not significantly affected by the interaction.
4-Number of pods / plant, number of seeds / pod, pods weight / plant, seeds weight / plant, and seed yield / fad were significantly affected by the interaction in the first season. The highest yield was 14.37 ardab / fad, produced by Giza 716 combined with (0-F-F) pattern. In the second season, plant height, pods weight / plant, seeds weight / plant and seed yield/ fad were influenced by the interaction. The highest yield was 14.30 ardab / fad, produced by Giza 716 (0-F-F) pattern.
5-Protein %, protein yield, N%, P% and K% in faba bean seeds were not significantly affected by the interaction in both seasons.IV- Competitive relationships and yield advantages:
1-LER value was only 0.99 as an overall average of all patterns and the three varieties and in both seasons, which indicates no advantage for intercropping. Lf averaged 0.94 in 1998 / 99 and .0.93 in 1999/2000 as against Lo of 0.05 and 0.06 in the two successive seasons, respectively. In other words faba bean contribution reached 94 to 95% and onion made only 5 to 6% in LER value.
2-Relative crowding coefficient could not be calculated in 6 patterns in the first season and 5 patterns (out of 12 )in the second one as a result of the higher values of faba bean intercropped yield than the pure stand yield. K values of onion were very low and did not exceed 0.05 to 0.07, therefore the K values indicated yield disadvantage for intercropping faba bean and onion.
3-Aggressivity showed that faba bean was the dominant component with an overall average of + 2.22 in 1998/99 and + 1.88 in 1999/2000, and onion was the dominated component.
4-In conclusion, the results showed that faba bean is the ”Overstory” component and onion is the ”Understory”. The sever faba bean competitive abilities depressed onion growth and consequently intercropping patterns failed to achieve yield advantage.