الفهرس 
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Abstract
A field experiment was carried out in Shandaweel Agricultural Research Station, Sohag Governorate in two successive seasons of 2006/2007 and 2007/2008 to study the effect of sources, levels and number of application of nitrogen fertilization on yield and quality of sugarcane plants.
Every field trial included 27 treatments represent three sources of nitrogen, three levels of nitrogen and three number of N-application.
A split- split plot design with four replications was used in both seasons. Sources of nitrogen were allocated to the main-plots. Nitrogen levels were randomly distributed in the sub plots while number of N-application were distributed in the sub-sub plots. The experimental unit area was 21 m2 with 6 ridges of 3.5 meters in length and 1.0 m apart.
Sugarcane variety vis Phil. 8013 was planted on 15th March in the first season and 8th March in the second season and harvested after 12 months in both experiments.
The obtained results could be summarized as follows:
I. Effect of nitrogen sources, nitrogen fertilization levels, number of nitrogen application doses and their interactions on growth criteria.
1. Stalk height (cm.).
The results showed that stalk height was significantly affected by nitrogen source at 195 days after planting in both seasons, while at age 240 and 285 days after planting the effect was significantly in the 2nd season only.
Data revealed that nitrogen rate exhibited significant effect on stalk height at all growth stage in both seasons. Increasing nitrogen level from 180 up to 240 kg N/fed. was accompanied by an increase in stalk height.
The results showed that the differences among number of N-dose in affecting stalk height were significant throughout the growing season in the first and second season crops.
The interaction effect of nitrogen source x nitrogen levels on stalk height was significant effect in the second season only. The interaction effect of nitrogen source x number of N-application on stalk height was significant at 195 and 240 days age in the second season while, in the first season significant at 195 days only.
The interaction effect of nitrogen levels x number of N-application on stalk height had no significant effect on stalk height in both season except at 240 days age in the second season.
Stalk height was significantly affected by the interactions among the three studied factors at ages of 195 days in the first season and 240 days in the second season.
2. Stalk diameter (cm.).
With regard to stalk diameter of sugar cane, it is clearly show that was significantly affected by nitrogen sources at 240 days after planting in the first season and at age 195 and 240 days after planting in the second season. Fertilization sugar cane by ammonium sulphate tended to produce more and stalks thicker than urea or ammonium nitrate at all growth stage in both seasons.
The effect of nitrogen fertilization levels was significant in the second season only. There are graduated and significant increase in this trait as N- level was increased up to 210 kg N/fed.
Number of doses application N affecting on stalk diameter significantly throughout the growing season in the first and second season crops. Increasing number of N-dose from 2 to 3-equal dos was accompanied by a substantial increase in stalk diameter.
Regarding, the interaction effect of nitrogen source x nitrogen levels on stalk diameter was significant effect at only 285 day in both seasons. Data presented that the highest values obtained from using ammonium sulphate at 210 and 240 kg N/fed. in the first and second season, respectively.
The interaction effect of nitrogen source x number of application on stalk diameter was significant at 195 and 240 days age in the second season.
Insignificant influence on stalk diameter was found due to the effect of the interaction between nitrogen fertilization levels and number of N-application at all growth stage in the both seasons.
Stalk diameter was insignificantly affected by the interaction among the three studied factors at all growth stage in the first and second seasons.
3. Leaf area (cm2.).
Differences among nitrogen source had a significant effect on leaf area at all growth stage in both seasons, at all growth stage, the largest leaves resulted from fertilization with urea fertilizer, while using ammonium sulphate recorded the lowest values in all growth stage in both seasons.
Concerning the effect of nitrogen level, the results in revealed that leaf area was significantly affected by the applied N-level at the three growth stage in both seasons.
In respect to number of N-dose on this trait, the results cleared that the leaf area was significant affected by the applied number of N-dose at all growth stage in both seasons.
Regarding, the interaction effect of nitrogen source x nitrogen level on leaf area was significant effect at all growth stage in both seasons.
The interaction effect of nitrogen source x number N-dose on leaf area was significant effect at 285 days in the first season and 195 and 240 in the second season. The interaction effect of nitrogen levels x number N-dose on leaf area was significant at all growth stage in both seasons, except, at 195 days after planting in the first season.
Insignificant influence on leaf area was found due to the effect of the interaction among the three studied factors at all growth stage, except, at 240 days in the first season.
4. Total soluble solids percentage (TSS%).
The results indicated that the differences among nitrogen source had a significant effect on total soluble solids percentage at 300 days of age in the first season and 210 and 255 in the second season. The highest total soluble solid was obtained by using Ammonium sulphate at all ages in both seasons.
The results clearly show that total soluble solids percentage was increased with increasing plant age and increased with increasing nitrogen fertilization levels in both seasons.
Differences among number of N-dose in affecting on TSS% was significantly in the second season only. Increasing number of N-dose from 2 up to 4-equal dose was accompanied by a substantial increase in TSS%. Regarding, the interaction effect of nitrogen source x nitrogen levels on TSS% was significant effect at 210 and 255 days in the second season only.
The interaction effect of nitrogen source x number of N-dose on TSS% was significant effect at 210 and 255 days in the second season.
The interaction effect of nitrogen levels x number of N-application on TSS% had no significant effect on TSS% in both season except, at 255 and 300 days after planting in both seasons.
Insignificant influence on TSS% was found due to the effect of the interaction among the three studied factors at all growth stage in the first and second seasons except 210 days in second season.
II. Effect of nitrogen sources, nitrogen fertilization levels, number of nitrogen application doses and their interactions on yield and yield components.
1. Stalk height (cm.).
The results obtained cleared that cane stalk height was significantly influenced by the studied nitrogen sources in second season only. It was found that stalk height was increased by using urea while, the lowest was obtained from using ammonium sulphate.
The available data distinctly show that the applied nitrogen levels attained a positive and significant effect on stalk height in both seasons.
Differences among number of N-dose in affecting stalk height was significantly in both seasons.
All types of the interaction were insignificant, except, nitrogen source x nitrogen levels in the second season only.
2. Stalk diameter (cm.).
With regard to stalk diameter of sugarcane at harvesting, data clear that the evaluated of nitrogen sources did not differ significantly on stalk diameter in the both seasons.
The available data reveal that N-fertilization levels had significant effect on stalk diameter in the second season only.
Concerning the influence of number of N-dose in affecting stalk diameter, the available data showed that there were a significant increase in stalk diameter with increasing number of doses up 3-equal dose in both seasons.
All types of interaction were insignificant, except, nitrogen source x nitrogen levels in the first season only.
3. Stalk fresh weight (kg.).
Data cleared that the examined three nitrogen sources differed significantly in stalk fresh weight in the 1st and 2nd seasons.
The results indicated that stalk fresh weight of sugarcane increased gradually and significantly as a result of increasing nitrogen fertilization level from 180 to 210 and to 240 kg N/fed. in both seasons.
Data showed that stalk fresh weight was significant affected by number of N-dose in both seasons.
All types of interaction were insignificant in the first season, while in the second season all types interaction was significantly.
The interaction among the three studied factors was significant effect on stalk fresh weight in 2nd seasons only.
4. Number of internodes per stalk.
Data showed that number of internodes/stalk was significant affected by nitrogen sources in both seasons. Using urea gave the highest value in both seasons.
Data given obviously show that increasing fertilization level of nitrogen caused a relative increase in the internodes/stalk in both seasons.
Data showed that internodes/stalk was significant affected by the number of N-dose in both seasons, using fertilization on 4-equal attained the highest internodes/stalk in both seasons.
All types of interaction were insignificant, except, nitrogen source x nitrogen levels in both seasons.
5. Number of millable cane per feddan at harvest.
The results pointed to a significant variance among nitrogen sources in number of millable canes/fed. in the second season only. Using urea recorded the highest number of millable canes/fed. produced in both seasons.
Data obviously show that increasing fertilization level of nitrogen caused a relative increase in the number of millable canes/fed. in the first and second seasons, number of millable cane stalks gradually increased as nitrogen rate increased up to 240 kg N/fed.
Data clear that increasing number of N-dose to 2 and 4-equal dose increased number of millable canes/fed. in both seasons.
All types of interaction were insignificant in the first season, while in the second season all types interaction was significantly.
6. Cane yield (ton/fed.).
Cane yield was significantly affected by nitrogen sources in both seasons. Applications of urea fertilizer gave the highest cane yield, while the lowest cane yield was obtained by using ammonium sulphate.
Regarding the effect of nitrogen levels on cane yield ton/fed., it was significant in both seasons. Data presented that the highest values were obtained from application 240 kg N/fed. which gave 58.72 and 58.42 ton/fed. in the 1st and 2nd seasons, however, the lowest yield was obtained from application 180 kg N/fed. in both seasons.
Data clear that increasing number of N-dose to 3 and 4-equal dose increased cane yield/fed. in both seasons.
The interaction effect between nitrogen sources x nitrogen levels on cane yield ton/fed was significant in the second season only.
The results show that nitrogen sources x number of N-dose interactions had significant effect on cane yield ton/fed. in the second season only.
Cane yield ton/fed was insignificantly affected by interaction between nitrogen levels and number of N-dose in the 1st and 2nd seasons.
The interactions among the three studied factors had insignificant influence on cane yield/fed in the 1st and 2nd seasons.
7. Top yield (ton/fed.).
Top yield ton/fed. was significantly affected by nitrogen sources in the second season only. Applications of urea fertilizer gave the highest top yield, while the lowest top yield ton/fed. was obtained by using ammonium sulphate.
Regarding the effect of nitrogen levels on top yield ton/fed., it was significant in both seasons. Data presented that the highest values were obtained from application 240 kg N/fed. which gave 15.35 and 15.47 ton/fed. in the 1st and 2nd seasons, however, the lowest yield was obtained from application 180 kg N/fed. in both seasons.
Data clear that increasing number of N-dose from 2 up to 4-equal dose increased top yield ton/fed. in both seasons.
Top yield ton/fed. was insignificantly affected due to the interaction between nitrogen sources x nitrogen levels and interaction nitrogen sources x number of N-dose at harvest in both seasons.
Top yield ton/fed. was significantly influenced by the interaction between nitrogen levels x number of N-dose at harvest in both seasons.
The interactions among the three studied factors had insignificant influence on cane yield/fed. in the 1st and 2nd seasons.
8. Sugar yield (ton/fed.):
Concerning the effect of nitrogen sources on average sugar yield ton/fed was significant in the second season only. Sugar yield was increased with applying ammonium nitrate and ammonium sulphate, while using urea fertilizer gave the lowest value for this trait in the second season.
In addition, the effect of nitrogen levels on sugar yield was significant in the second season, data presented show that the highest values of sugar yield 7.02 ton/fed. in the second season were recorded from application 240 kg N/fed. However, the lowest values of this trait, were resulted 6.83 ton/fed. recorded from application 180 kg N/fed.
Concerning the influence of number of N-dose in affecting sugar yield ton/fed., the available data showed that there were a significant increase in sugar yield ton/fed. with increasing number of doses up 4-equal in both seasons.
The interaction effect between nitrogen sources and nitrogen levels on sugar yield yon/fed. was significant in both seasons.
Data showed that nitrogen sources x number of doses N and nitrogen fertilization levels x number of N-dose interactions had significant effect on sugar yield/fed in the first season only.
Differences in sugar yield/fed. due to the interaction among the three studied factors in the second season only, in this season, the maximum sugar yield/fed 7.44 ton/fed. was recorded using ammonium nitrate at rate 210 kg N/fed. and applied on 4-equal.
III- Effect of nitrogen sources, nitrogen fertilization levels, number of nitrogen application doses and their interactions on juice quality.
1. Brix percentage (%).
The results indicated that the evaluated the three nitrogen sources differed significantly in brix % in both seasons.
Differences among nitrogen rates in affecting in brix% was significant in both seasons.
Concerning the influence of number of N-dose in affecting brix%, the available data showed that there were a significant increase in brix% with increasing number of doses.
Moreover, the interaction effect of nitrogen sources x nitrogen levels on brix percentage was significant in both seasons.
Brix percentage was insignificantly affected due to the interaction between nitrogen sources x number of N-dose at harvest in both seasons.
With regard to the interaction effect of nitrogen levels x number of N-dose on brix percentage was significant in the first season only.
The interaction among the three studied factors was significant effect on brix percentage in the 1st and 2nd seasons.
2. Sucrose percentage (%):
Data show the effect on nitrogen sources on sucrose percentage in cane juice was significantly affected by nitrogen sources in both seasons.
Concerning the effect of nitrogen fertilization levels on sucrose percentage, the results obtained indicated that sucrose percentage positively and gradually responded to the increase in the applied N-dose up to 210 kg N/fed.
Sucrose percentage was significant affected by influence of number of N-dose in both seasons.
In respect to the interaction effects, data show a significant effect on sucrose percentage referred to the interaction between nitrogen sources and nitrogen level at harvest in the first season only.
Differences in sucrose percentage due to the interaction among nitrogen sources x number of N-application were significant in the first season only.
As shown nitrogen fertilization levels x number of N-dose interaction had significant effect on sucrose percentage in the first season only.
The 2nd order interaction among the three studied factors did not affect sucrose percentage at harvest in both seasons.
3- Purity percentage (%).
Results show the significant differences among the averages of purity percentage in the first season as affected by nitrogen sources.
Data obviously showed that increasing nitrogen fertilization levels caused a relative decreased in purity%, this effect was significant in the first season only.
Purity percentage was significant affected by influence of number of N-dose in 2nd season only. The interaction effect of nitrogen sources x nitrogen levels on purity percentage was significant in both seasons. With regard to the interaction effect of nitrogen sources x number of N-dose and nitrogen levels x number of N-dose on purity percentage was significantly effected in the first season only.
The 2nd order interaction among the three studied factors affected juice purity percentage% at harvest in the 2nd season only.
4. Sugar recovery percentage (SR%).
Effect of nitrogen sources on sugar recovery percentage was significant in both seasons.
The recorded data distinctly show that a nitrogen fertilization levels was significant effect on sugar recovery percentage in the first season.
Sugar recovery percentage was significant affected by influence of number of N-dose in the 1st season only.
With regard to the interaction effect of nitrogen sources x nitrogen levels on sugar recovery percentage was significant in both seasons.
Moreover, the interaction effect of nitrogen sources x number of N-dose on sugar recovery percentage was significant in the first season only.
The interaction between nitrogen levels and number of N-dose had a significant influence on sugar recovery% in the 1st season only. Sugar recovery percentage was insignificantly affected by the 2nd order interaction among the three studied factors in the 1st and 2nd seasons.
5. Fiber percentage in cane stalk (%):
The results revealed that the tested nitrogen sources differed significantly in stalk fiber percentage in both seasons.
The results showed that fiber percentage in stalk was significantly affected by nitrogen fertilization levels in both season.
Fiber percentage in cane stalks was significantly affected by the number of N-dose in both seasons.
As for the interaction effects, the results revealed that stalk fiber percentage in cane stalk was significantly affected the interaction between nitrogen sources x nitrogen fertilization levels at harvest in the second season only.
Fiber percentage in cane stalk was significantly influenced by the interaction between nitrogen sources x number of N-dose at harvest in the first season. The interaction between nitrogen levels x number of doses N was significant effect on fiber% in stalk in the 2nd season. The interaction among the three studied factors did not affect fiber% in cane stalk in both seasons.
6. Nitrogen percentage in stalks and leaves (%):
Data pointed to a significant variation among the tested sources of nitrogen in nitrogen percentage in stalk and leaves in both seasons.
The results revealed that increasing nitrogen fertilization level from 180 to 240 kg N/fed. was accompanied with a gradual and significant increase in nitrogen percentage in stalks and leaves at harvest, in both seasons.
Data in showed that nitrogen percentage in stalks and leaves was increased gradually and significantly as the applied number of N-dose were raised from 2 to 4-equal dose, in both seasons.
Concerning the interaction effects, data indicated that the interaction between nitrogen sours x nitrogen fertilization levels affected significantly nitrogen percentage in stalks and leaves at harvest in both seasons.
Nitrogen percentage in leaves and stalks was insignificantly by the interaction between nitrogen sources and number of N-application at harvest in both seasons. Nitrogen percentage in stalk was significant affected by the interaction between nitrogen levels and number of doses application at harvest in the both seasons. On the contrary, N % in leaves of sugarcane was not affected by this interaction, in both seasons. The interaction among the three studied factors had a significant effect on nitrogen percentage in leaves of sugarcane the in both seasons, while, N % in cane stalks was significantly influenced by this interaction in the 2nd season only.
Conclusion
Based on the results obtained of this study, used urea fertilizer with 240 kg N/fed. in 4-equal doses gave the highest yield under condition of Sohag Governorate.