الفهرس 
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Abstract
This study was carried out at the experimental field of the Horticulture Research Station at Al Qanater-Al Khairya, Agriculture Research Center (ARC), for two successive seasons (2011/2012 and 2012/2013).
The study aims to investigate the effect of mineral and biological fertilization on the growth and active ingredients of Majorana hortensis plant.
The experiment was designed as complete random strips to study the effect of Azotobacter and Azospirillum as various sources of fertilizer and alternative of environmental pollution from NPK mineral fertilizers.
The plants were harvested in 3 separated cuts /season (first week of May, first week of August and first week of November for both seasons) by cutting the vegetative parts of all the plants 5 cm above the soil surface .
The following measurements were recorded at each cut:
- heights at different cuts (cm).
- Number of branches /plant at different cuts.
- Herb fresh weight (g/plant ( at different cuts.
- Herb dry weight (g/plant) at different cuts.
- Oil percentage (%) at different cuts.
- Percentage of total nitrogen, total phosphorus, total potassium, Chl (A), Chl (B) and carotenoids in 3rd cut from Magorana hortensis in season 2012/2013.
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The plants received the following fertilization treatments
T1- Uninoculated (Control) + full dose of NPK.
T2- Azotobacter chroococcum.
T3- Azospirillum lipoferum.
T4- Azotobacter chroococcum + Azospirillum lipoferum
T5- Azotobacter chroococcum +25% NPK
T6- Azotobacter chroococcum +50% NPK
T7- Azospirillum lipoferum +25% NPK
T8- Azospirillum lipoferum +50% NPK
T9- Azotobacter chroococcum + Azospirillum lipoferum +25% NPK
T10- Azotobacter chroococcum + Azospirillum lipoferum +50% NPK
1- The results of Azotobacter chroococcum in combination with 50% of recommended NPK dose (T10) gave the tallest plant at first cut in both years. Moreover, second and third cuts showed decline in plant heights compared to first cut.
2- Azospirillum lipoferum or combination of both strains showed significant increase in plant height. The maximum significant increase of plant height was 63.7 cm at the first cut of T10 treatment. T10 and T3 showed the tallest plant in the first and second cut respectively of 2011. However, third cut height under both strains in combination application in T8, T9 and T10 gave the taller plants 40.7, 40.3 and 39.3 respectively. T4 and T10 gave tallest plant 49.3 and 52.0 cm at first cut of 2013.
3- The high number of branches abstained in three cuts 20.3, 29.3, 38.0 No. /plant from T10, T9 and T6 respectively, whereas the lowest number obtained were 11.0, 19.0, and 28.0 in 2011/2012.
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4- Fresh weights were positive increment in the second cut compared to the first cut and reduction was observed in the third one.
5- Alteration of mineral fertilization with biofertilizer showed significant advances in cultivation of Majorana hortensis. Fresh weight showed variability among treatments in both growing seasons and different cuts.
6- In both years and all cuts treatments showed significant difference than control. In which, reducing amount of N, P, K and use single or combined strains of Azospirillum lipoferum and Azotobacter chroococcum gave better result than control.
7- Reduction synthetic fertilizer to one quarter or half gives better results than non-fertilized control or odd use of biofertilizer. Azotobacter chroococcum with reduced amount of chemical fertilizer gives better results than Azospirillum lipoferum or in combination together.
8- Overall difference between using Azotobacter chroococcum combined with synthetic fertilizer gave 10-55% than control and showing better tendency by 10% than use of Azospirillum lipoferum.
9- T6 has increased fresh weigh significant in all cuts of first year of 2011. T6 and T7 showed the highest fresh weight in the first cut being 46.6 and 48.2 respectively. However, T6 (Azotobacter +½ NPK) and T10 (Azotobacter+Azspirillum+½ NPK) treatments showed significant increase in fresh weight being 50.2 and 89.9 g/ plant in the 2nd and 3rd cut respectively of season 2012/2013 in the second year.
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10- T7 demonstrated significant affect on fresh weight of third cut in the first year gives better perform. First and second cuts gave better fresh weight in 2013 compared for what obtained in the first year.
11- Cut age of dry weight of the first year was higher than second year was third cut and first cut showed the highest % DW in first and second year respectively.
12- At the first cut of both years non significant differs or slight difference among treatments was observed, while third cut in the first year gives better perform.
13- First year showed higher accumulation of dry weight.High Increase accumulation of dry matter was obtained in T3 (Azospirillum) & T6 (Azotobacter +½ NPK) compared to T4 (Azotobacter +Azspirillum) &T7 (Azospirillum+¼ NPK) for cut age of dry weight of first year at third cut was higher than second year.
14- Use of biofertilizer stimulates accumulation of oil contents than application of synthetic fertilizers. First & second cut showed the highest accusation of oil in first and second years. However, first cut of the first year showed the highest accumulation among different cuts.
15- T6 showed 0.87% accumulation, while control treatment gave 0.54%. Moreover, T6 showed stable tendency at different cuts in both years, which reveal good synergy between low dose of NPK and Azotobacter- Azospirillum on accumulation of oil.
16- N, P and K percentages in marjoram plant herb were considerably influenced by the inoculation with
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A.chroococcum and Azospirillum lipoferum or their mixture combined with NPK fertilizers.
17- Inoculating Magorana hortensis plants with Azospirillum + 25% NPK resulted in the highest N percentages. But the highest P and K percentages were obtained by fertilizing the plants with a mixture of the strains (Azotobacter and Azospirillum) without NPK fertilizers and Azotobacter +50% NPK respectively. This is due to the effect of all strains. T7 and T8 gave the highest and lowest Carotenoids percentage respectively.
18- T6 and T7 gave the maximum Chl (A) and Chl (B) being 1.1600 and 1.250 respectively