الفهرس 
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Abstract
The present investigation included three orchard experiments conducted during 2007 and 2008 seasons on the third and fourth Grand Nain banana ratoons grown in clay loamy soil in plantain belonging to Horticultural Research Station at Elqanater Elkhairia, Kalubia Governorate.
Mats (plantain holes) were 3.5 x 3.5 m apart with three productive rations per each (3 suckers were annually selected and remained to grow for the consecutive cropping). The suckers devoted for this study were healthy, nearly uniform in growth vigour and received regularly the recommended horticultural practices.
The three evaluated experiments were handled as follows:
5.1. Experiment I: A comparative study on the effect of fast and slow release nitrogen fertilizers form and rate on growth and fruiting of banana plant.
According to the studies of Horticulture Institute on nitrogen fertilization requirements for banana plants, the recommended nitrogen fertilization rate is 3-4 kg ammonium sulfate (20.5% N) / stool / year i.e. 600-800 g actual N / stool / year applied at fortnight intervals starting from April up to October. Thereupon, this experiment evaluated two forms and rates of both fast (conventional) and slow release nitrogen fertilizers as follows:
1- Ammonium sulfate [(NH4)2SO4 – 20.5% N] as fast release nitrogen fertilizer at the rate of 200 and 300 g actual N / plant / year.
2- Ammonium nitrate (NH4NO3 – 33.5% N) as fast release nitrogen fertilizer at the rate of 200 g actual N / plant / year.
3- Phosphorus coated urea (PCU – 37% N) as slow release nitrogen fertilizer at the rate of 200 and 300 g actual N/plant/year.
4- Urea formaldehyde-urea form- (UF – 37% N) as slow release nitrogen fertilizer at the rate of 200 and 300 g actual N / plant / year.
The tested amounts of fast release nitrogen fertilizers per plant were fractionated into equal doses applied at monthly intervals from April up to October. Besides, the amounts of slow release nitrogen fertilizers were applied in April of both seasons.
Consequently, this study is a factorial experiment consists of two nitrogen fertilizer sources and each one included two forms with two rates. The complete randomized block design with three replicates was used for arranging the different investigated treatments. Each replicate was represented by four stools with three similar plants (ratoons) left per each for cropping in current season and following one.
The obtained results could be summarized as follows:
5.1.1. Vegetative growth
The higher N fertilization rate (300 g N/plant/year) surpassed the lower N fertilization rate (200 g N/plant/year) in enhancing pseudostem height and leaf area. Besides, the higher N fertilization rate failed to induce any positive effect on pseudostem circumference, No. of green leaves/plant and leaf dimensions (length and width) of banana plant cv. Grand Nain.
Furthermore, the application of N fertilization through slow release fertilizers showed superiority than the application through fast release fertilizers in improving all tested vegetative growth parameters i.e. pseudostem height and circumference, No. of green leaves/plant, leaf dimensions (length and width) and leaf area of banana plant cv. Grand Nain.
On the other hand, the combinations of UF and PCU particularly those with higher N fertilization rate (300 g N/plant / year) surpassed the corresponding ones of ammonium sulfate and ammonium nitrate in enhancing the studied vegetative growth parameters i.e. pseudostem height and circumference, No. of green leaves/plant, leaf dimensions (length and width) and leaf area of banana plant cv. Grand Nain.
5.1.2. Leaf mineral content
Increasing N fertilization rate from 200 to 300 g N/plant/year for banana plants increased leaf N and Mg content. On the other hand, the higher N fertilization rate failed to induce an additional effect on leaf P, K, Ca, Fe, Mn, Zn and Cu content.
The application of N fertilization through slow release fertilizers induced a remarkable positive effect on leaf N, P, K, Ca, Mg, Fe, Mn and Zn content than did fast release fertilizers. On the other side, N fertilizer source had no significant effect on leaf Cu content.
Briefly, the application of slow release N fertilizers in the form of UF and PCU produced in most cases, similar and higher positive effect on leaf N, P, K, Ca, Mg, Fe, Mn and Zn content than did fast release N fertilizers in the form of ammonium sulfate and ammonium nitrate. Besides, leaf Cu content didn’t show any response to N fertilizer form.
The combinations of UF and PCU at 200 and 300 g N/plant/year proved to be the superior interactions in enhancing the studied leaf mineral content of banana plants as compared with the corresponding ones of ammonium sulfate and ammonium nitrate hence, they produced in most cases similar and higher (specially with higher N fertilizer rate) values of leaf N, P, K, Ca, Mg, Fe, Mn and Zn content. Besides, the tested combinations failed to induce any significant effect on leaf Cu content.
5.1.3. Blooming and fruiting
Increasing N fertilization rate from 200 to 300 g N/plant/year for banana plants failed to induce any remarkable effect on the studied blooming and fruiting parameters of banana plants during the two seasons of study. These studied blooming and fruiting parameters were: age of suckers at bunch shooting (days), time from bunch shooting to harvesting (days), bunch weight (kg), No. of hands/bunch and No. of fingers/bunch.
Shortly, the application of N fertilization through slow release fertilizers showed higher efficiency in enhancing the studied blooming and fruiting parameters of banana plants than did fast release fertilizers in both seasons of study. The studied blooming and fruiting parameters were: age of suckers at bunch shooting (days), time from bunch shooting to harvesting (days), bunch weight (kg), No. of hands / bunch and No. of fingers / bunch.
Briefly, the application of N slow release N fertilizers in the form of UF and PCU produced statistically similar (in most cases) and more enhancing effect (with the superiority for UF form) on blooming and fruiting parameters than did fast release N fertilizers forms (ammonium sulfate and ammonium nitrate) in both seasons of study. These studied blooming and fruiting parameters were: age of sucker at bunch shooting (days), time from bunch shooting to harvesting (days), bunch weight (kg), No. of hands/bunch and No. of fingers / bunch.
The combinations of UF and PCU (with the superiority for UF) at 200 and 300 g N/plant/year (with the superiority of higher N fertilization rate) produced in most cases similar and more remarkable effect on shortening the time required for the sucker to reach bunch shooting and time elapsed between bunch shooting to harvesting and in the same time, they increased bunch weight, No. of hands / bunch and No. of fingers / bunch in comparison with the analogous ones of ammonium sulfate and ammonium nitrate.
5.1.4.I. Fruit physical properties
Raising N fertilization rate from 200 to 300 g N/plant/year failed to exert a pronounced positive effect on the studied fruit physical traits i.e. finger weight (g), length (cm), diameter (cm), pulp weight (g) and pulp (%) in both seasons of study.
The application of N fertilization through slow release fertilizers surpassed fast release fertilizers in enhancing fruit physical properties namely finger weight (g), length (cm), diameter (cm), pulp weight (g) and pulp (%).
Briefly, the application of slow release fertilizers in the form of UF and PCU produced similar and higher positive effect on finger weight (g), length (cm), diameter (cm), pulp weight (g) and pulp (%) than did fast release fertilizers in the form of ammonium sulfate and ammonium nitrate in both seasons of study.
The combinations of UF and PCU at 200 and 300 g N/plant/year (with superiority for UF at 300 g N/plant/year) proved to be the superior combinations in improving finger weight (g), length (cm), diameter (cm), pulp weight (g) and pulp (%) than the combinations of ammonium sulfate and ammonium nitrate in both seasons of study.
5.1.4.II. Fruit chemical properties
Increasing N fertilization rate from 200 to 300 g N/plant/year didn’t affect the studied fruit chemical properties i.e. T.S.S. (%), acidity (%), starch (%) and total sugars (%) in both seasons of study.
The application of N fertilizers through slow release fertilizers enhanced finger starch and total sugars content and failed to affect finger T.S.S. and acidity content in comparison with fast release N fertilizers in both seasons of study.
Briefly, the application of slow release fertilizers in the form of UF and PCU exerted similar and higher positive effect on finger starch and total sugars content, but failed to produce any significant effect on finger T.S.S and acidity content in comparison with fast release N fertilizers in the form of ammonium sulfate and ammonium nitrate in both seasons of study.
The combinations of N fertilization rate and form failed to exert any remarkable effect on finger T.S.S., acidity and total sugars content in both seasons of study. Besides, UF and PCU combinations at 200 and 300 g N/plant/year proved to be the superior interaction in enhancing starch (%) of banana fingers in comparison with ammonium sulfate and ammonium nitrate combinations.
Conclusively, it is preferable to satisfy N fertilization requirements for banana plants through slow release N fertilizer in the form of UF or PCU at the rate of 200 g N/plant/year to enhance plant growth, nutritional status, yield and fruit quality.
5.2. Experiment II: A comparative study on the effect of soil application and foliar spray of nitrogen fertilizers on banana plant.
According to the previous studies on banana fertilization, Youssef (1968) recommended the fertilization of banana plants with 600 g absolute nitrogen / stool (three plants / stool) / year through soil application. In other term, the recommended nitrogen fertilization for banana plants is 200 g actual N / plant / year. This amount was recommended to be fractionated into equal doses applied at equal intervals (fortnight interval) through the year started from March up to October (Tadros, 1973). The recommended amount of nitrogen fertilization (200 g N/plant/year) used in the present study was applied as soil application only (100%) in the form of ammonium sulfate (20.5% N) or in partner with foliar spray of urea (46% N) at the compensation of 75, 50 and 25% of the recommended nitrogen fertilization.
Therefore, the evaluated treatments in the present experiment were as follows:
(a) 100% of the recommended nitrogen fertilization (200 g actual N / plant / year) was employed through soil application in the form of ammonium sulfate (20.5% N) i.e. 976 g ammonium sulfate / plant/year as a control.
(b) 75% of the recommended nitrogen fertilization was employed through soil application in the form of ammonium sulfate (732 g ammonium sulfate / plant / year), whereas the rest 25% of the recommended nitrogen fertilization was satisfied through foliar spray with urea (46% N) at 1% (109 g urea / plant / year) applied in foliar spray form.
(c) 50% of the recommended nitrogen fertilization was practiced through soil application in the form of ammonium sulfate (488 g ammonium sulfate / plant / year) and the other half (50%) of the recommended nitrogen fertilization was satisfied through urea foliar spray at 1% (218 g urea / plant / year).
(d) 25% of the recommended nitrogen fertilization was conducted through soil application in the form of ammonium sulfate (244 g ammonium sulfate / plant / year), whereas the rest 75% of the recommended nitrogen fertilization was justified through urea foliar spray at 1% (327 g urea / plant / year).
Furthermore, the amount of ammonium sulfate of each treatment was fractionated into equal doses and applied at fortnight intervals from March up to October. Besides, the amount of urea of each treatment was fractionated to be applied as foliar spray at 1% at equal intervals starting from March up to October. Super film at 0.1% as wetting agent was added to all urea solutions. A water-meter was used to control the quantity of sprayed urea solution for each plant.
The complete randomized block design was chosen for this experiment. Four blocks of banana plants cv. Grand Nain and each block consisted of six plots. Thus, the individual treatment was replicated six times.
The obtained results could be summarized as follows:
5.2.1. Vegetative growth
The application of recommended N fertilization at 75% of the required N through soil application (in the form of ammonium sulfate) and the rest 25% of the needed N through foliar application (in the form of urea sprays at 1%) proved to be the superior method of application in enhancing the studied vegetative growth parameters of banana plant cv. Grand Nain. These vegetative growth traits were: pseudostem height (cm) and circumference (cm), No. of green leaves / plant, leaf length (cm) and leaf area (m2). Besides, the application of recommended N fertilization in two equal doses through soil application (50%) and foliar spray (50%) ranked the second in enhancing the previously mentioned vegetative growth parameters, followed descendingly by the application of one quarter of the recommended N fertilization through soil application and the other three quarter of the required N fertilization through foliar application in both seasons of study. On the contrary, the application of all recommended N fertilization through soil application only showed to be the least efficient method of enhancing the aforementioned vegetative growth parameters. Moreover, leaf width didn’t show any significant response to the different compensation alternative ratios of soil application and foliar application in satisfying the recommended N fertilization for banana plants.
5.2.2. Leaf mineral content
The application of 75% of recommended N fertilization for banana plant through soil application and the rest (25% N) through foliar spray showed to be the superior treatment in enhancing leaf N and Mg content in both seasons and statistically similar enhancing effect on leaf Ca, Fe (in the second season, only) and Zn content to that produced by those received 50% of recommended N fertilizers through soil application and the other half of recommended N fertilization through foliar sprays. Moreover, dividing the required N fertilization for banana plants into two equal doses applied through soil and foliar application came in the second order in enhancing leaf content of N and Mg (in the first season, only). Beside, the application of one quarter of required N fertilization for banana plant through soil application and three quarter through foliar spray induced positive effect on leaf N content in both seasons and leaf content of Mg and Zn in the first season, only. On the contrary, the application of all required N fertilization through soil application only recorded the lowest values of the studied leaf mineral content in both seasons. Furthermore, the different alternative ratios of soil application and foliar application in satisfying the needed N fertilization for banana plants failed to induce a remarkable effect on leaf P, K, M and Cu content in both seasons of study.
5.2.3. Blooming and fruiting
Briefly, the application of 75% of recommended N fertilization through soil application and the rest (25% of the needed N) through foliar application produced the highest pronounced effect on shortening the time required for the sucker to reach bunch shooting and the period needed for these shooted bunches to attain harvesting and highest positive effect on No. of fingers / bunch in both seasons of study. Moreover, the application of one quarter of recommended N fertilization through soil application and the other three quarter through foliar spray surpassed the application of one half of recommended N fertilization through soil application and the other half through foliar spray in shortening the time from bunch shooting to reach harvesting. Besides, the different compensation ratios of soil and foliar application of the recommended N fertilization induced similar positive effect on bunch weight and No. of hands / bunch in both seasons of study. On the contrary, banana plants received all their recommended N fertilization through soil application, only required the longest time for the suckers to reach bunch shooting and the shooted bunches to attain harvesting and recorded the lowest values of bunch weight, No. of hands / bunch and No. of fingers / bunch.
5.2.4.I. Fruit physical properties
The application of three quarter of recommended N fertilization for banana plant through soil application and the other one quarter through foliar sprays proved to be the most efficient application method in recording the highest values of finger, weight length, diameter and pulp weight in both seasons of study. Besides, dividing the recommended N fertilization into two equal halves applied through soil and foliar surpassed the aforementioned N fertilization application method in enhancing pulp percentage and came next to the previously mentioned N application in increasing finger length and pulp weight. Moreover, the application of the recommended N fertilization through soil and foliar application in equal proportion induced similar positive effect on finger weight and finger diameter to that produced by dividing the recommended N fertilization into one quarter applied through the soil and the other three quarter applied through foliar spray in both seasons of study. On the contrary, the application of all recommended N fertilization for banana plants through the soil scored the lowest values of finger weight, length, diameter and pulp weight.
5.1.4.II. Fruit chemical properties
Satisfying 75% of N fertilization requirements for banana plants through soil application and the rest (25%) through foliar spray or dividing the recommended N fertilization into two halves applied equally through soil and foliar application produced similar and higher positive effect on finger T.S.S., starch and total sugars content. Besides, the previously mentioned two application methods of recommended N fertilization at alternative ratios produced similar reductive effect on finger acidity content in the first season, only. Moreover, satisfying one quarter of recommended N fertilization through soil application and three quarter through foliar spray induced the lowest positive effect on finger starch and total sugars content and reduced finger total acidity content in the first season, only as well as failed to affect finger T.S.S. content in comparison with satisfying the recommended N fertilization through soil application, only.
Consequently, N fertilization of banana plant cv. Grand Nain at alternative ratios of 75% of recommended N fertilization through soil application and 25% of needed N fertilization through foliar application (1% urea spray) showed to be a good system in improving plant growth, nutritional status, yield and fruit quality.
5.3. Experiment III: Effect of Fe, Mn and Zn foliar spray and active dry yeast on growth, fruiting and fruit quality of banana plants.
The effect of foliar sprays with iron, manganese and zinc in chelated form and soil application of active dry yeast on Grand Nain banana plant was handled as follows:
(1) Plants sprayed with tap water ”control”.
(2) Plants sprayed with 0.1 and 0.2% Fe in the chelated form.
(3) Plants sprayed with 0.1 and 0.2% Mn in the chelated form.
(4) Plants sprayed with 0.2 and 0.4% Zn in the chelated form.
(5) Plants received 2 and 4% active dry yeast through soil application.
(6) Plants sprayed with 0.1% Fe and supplemented with 0.1% Mn and 0.2% Zn as well as 2% active dry yeast through soil application.
(7) Plants sprayed with 0.2% Fe provided with 0.2% Mn and 0.4% Zn, besides, 4% active dry yeast through soil application.
The tested micronutrients i.e. Fe, Mn and Zn were applied in chelated form. Plants were sprayed three times a year i.e. April, July and October. Super film as wetting agent at 0.1% was added to all nutrient solutions and tap water ”control”. The nutrient solution sprays were sufficient to wet the plant thoroughly.
Furthermore, active dry yeast solutions (2 and 4%) were activated by dissolving the definite amount of active dry yeast in warm water (30°C) and adding Egyptian Treacle at the same rate and kept for 6 hours before application. Soil drench application of active dry yeast was conducted three times a year i.e. April, July and October.
The complete randomized block design was chosen for this experiment. Eleven blocks of banana plants cv. Grand Nain and each block consisted of six plots. Thus, the individual treatment was replicated six times.
The obtained results could be summarized as follows:
5.3.1. Vegetative growth:
Briefly, Fe sprays enhanced pseudostem circumference, leaf length (in the second season, only), leaf width and leaf area and failed to add an additional positive effect on pseudostem height and number of green leaves/ plant. Moreover, Mn sprays improved pseudostem circumference, leaf length and width (in the second season, only) and leaf area (in the first season, only). Furthermore, Zn sprays induced high positive effect on the studied vegetative growth parameters i.e. pseudostem height and circumference, number of green leaves / plant, leaf dimensions (length and width) and leaf area.
On the other hand, drench application of active dry yeast produced high pronounced effect on the previously studied vegetative growth parameters. In addition, the combinations of Fe (0.1 & 0.2%), Mn (0.1 & 0.2%), Zn (0.2 & 0.4%) and active dry yeast (2 & 4%) proved to be the superior treatments (particularly, the high concentration) in enhancing pseudostem height and circumference, number of green leaves / plant, leaf dimensions (length and width) and leaf area of banana plant cv. Grand Nain.
5.3.2. Leaf mineral content
Generally, foliar sprays with Fe (0.1 & 0.2%) increased leaf Mg and Fe content and failed to affect the rest studied leaf N, P, K, Ca, Mn and Zn content. Besides, Mn foliar sprays at 0.1 & 0.2% enhanced leaf Mg and Mn content and had no positive effect on leaf N, P, K, Ca, Fe and Zn content. Moreover, foliar sprays with Zn at 0.2 and 0.4% improved leaf N, P, K, Ca (in the second season, only), Mg and Zn content in both seasons.
On the other hand, drench application of active dry yeast at 2 and 4% produced a remarkable positive effect on the studied leaf N, P, K, Ca, Mg, Fe, Mn and Zn content. In addition, the combinations of Fe (0.1 & 0.2%), Mn (0.1 and 0.2%), Zn (0.2 & 0.4%) and active dry yeast at 2 and 4% showed to be the most efficient treatments in enhancing the previously mentioned leaf mineral content.
5.3.3. Blooming and fruiting
Shortly, foliar spray with Fe at 0.1 & 0.2% shortened the period from bunch shooting to harvesting, increased bunch weight and number of fingers / bunch, whereas age of suckers at bunch shooting and number of hands / bunch were not affected by Fe foliar sprays. Besides, Mn foliar sprays at 0.1 & 0.2% shortened the period elapsed between bunch shooting and harvesting, increased bunch weight (in the second season, only) and number of fingers / bunch. Also, Mn foliar sprays failed to affect age of suckers at bunch shooting and number of hands / bunch. Furthermore, Zn sprays (0.2 & 0.4%) hastened suckers to reach bunch shooting, shortened the period elapsed from bunch shooting to reach harvesting, increased bunch weight and number of fingers / bunch.
On the other side, drench application of active dry yeast shortened the age of suckers at bunch shooting, time from bunch shooting to harvesting, increased bunch weight, number of hands / bunch (4% treatment, only) and number of fingers / bunch. In addition, the combinations of Fe (0.1 & 0.2%), Mn (0.1 & 0.2%), Zn (0.2 & 0.4%) and active dry yeast (2 & 4%) exerted the most enhancing prospective effect on the previously mentioned blooming and fruiting parameters of banana plants cv. Grand Nain.
5.3.4. Fruit quality
5.3.4.I. Fruit physical properties
In summary, foliar spray with Fe and Mn at 0.1 & 0.2% failed to induce an additional positive effect on the studied fruit physical traits i.e. finger weight, length, diameter, pulp weight and pulp percentage. Besides, Zn sprays (0.2 & 0.4%) increased finger weight (at 0.4% Zn in the first season, only), finger length, pulp weight and pulp percentage, whereas finger diameter didn’t respond to Zn sprays.
On the other hand, drench application of active dry yeast at 2 & 4% produced positive effect on finger weight (in the first season, only), finger length, pulp weight and pulp percentage. In addition, the combination of Fe (0.1 & 0.2%), Mn (0.1 & 0.2%), Zn (0.2 & 0.4%) and active dry yeast (2 & 4%) produced the most enhancing effect on finger weight, length, pulp weight and percentage.
5.3.4.II. Fruit chemical properties
Briefly, foliar sprays with Fe (0.1 & 0.2%), Mn (0.1 & 0.2%), Zn (0.2 & 0.4%) and drench application of active dry yeast (2 & 4%) as well as their combinations enhanced finger starch content and failed to affect finger T.S.S., acidity and total sugars content.
According to the results of this experiment, it is preferable to spray banana plants cv. Grand Nain with a combination of Fe (0.2%), Mn (0.2%) and Zn (0.4%), supplemented with drench application of active dry yeast (4%) to achieve prospective effects on plant growth, yield and fruit quality. Moreover, it increases the tolerance of banana plants to control soil borne diseases, as well as leaf and fruit spot diseases.