الفهرس 
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Abstract
This experiment was conducted during the two consecutive seasons of 2005 and 2006 on forty-eight 15 years old Taimour and Zebda mango trees budded onto Balady mango rootstock. The trees were grown in a private mango orchard located at El- awam village, Minia district, Minia Governorate. The uniform in vigour trees of both cvs were planted at 7X7 meters apart. The soil texture of the tested orchard is loamy sand with a water table depth not less than two meters.
The present experiment included two factors (A and B). The first factor (A) included two mango cvs a1) Taimour and a2) Zebda. The second factor (B) comprised from the following eight treatments from inorganic, organic and bio sources of N as well as seaweed extract and yeast:
b1) Application of the recommended rate (R. R) of N i.e. 1000g N/tree completed via inorganic source only (100% inorganic) (4.85 Kg ammonium sulphate (20.6%N) /tree).
b2) Application of R. R. of N as 100% inorganic plus spraying seaweed extract at 0.1% plus yeast at 0.3%.
b3) Application of 75% of R. R. via inorganic source (3.64 Kg ammonium sulphate) plus 12.5% of R. R. via compost El-Neel (12.5%N) (5.81 Kg) plus 12.5% of R. R. via Biogen (125 g Biogen) /tree.
b4) The same previous treatments plus spraying seaweed extract at 0.1% plus yeast at 0.3%.
b5) Application of 50% of R. R. via inorganic source (2.43 Kg ammonium sulphate) plus 25% of R. R. via compost El-Neel (11.62 Kg) plus 25% of R. R. via Biogen (250 g Biogen) /tree.
b6) The same previous treatment plus spraying seaweed extract at 0.1% plus yeast at 0.3%.
b7) Application of 25% of R. R. via inorganic source (1.22 Kg ammonium sulphate) plus 37.5% of R. R. via compost El-Neel (17.43 Kg) plus 37.5% of R. R. via Biogen (375 g Biogen) /tree.
b8) The same previous treatment plus spraying seaweed extract at 0.1% plus yeast at 0.3%.
Therefore, the experiment included sixteen treatments (two mango cvs X eight treatments from inorganic, organic and biofertilization). Each treatment replicated three times, one tree per each. Ammonium sulphate (20.6%N) as a source of inorganic N was splitted into three equal batches and applied on the first week of March, April and May. Compost El-Neel (2.15% N, 65% O.M, 1.5% P and 1.3% K) as a source of organic N was added once at the first week of January. Biogen as a source of biofertilizer was added once at the first week of March. It was added in a circle 10 cm depth around each tree and covered with moist soil. Both seaweed extract (added in the form of powder Jevert containing some micro and macronutrients and certain antioxidants) and yeast (after activating with few sugars in warm water) were applied three times during each season , at the last week of March, middle of May and last week of June.
Completely randomized block design in a split plot arrangement was followed for carrying out statistical analysis. The mango cvs and the eight treatments from inorganic, organic and bio forms of N occupied the main and subplots, respectively.
For evaluating the response of both mango cvs. Taimour and Zebda to application of N either completely via inorganic source or via inorganic, organic, and bioforms with or without the foliar application of seaweed extract and yeast on yield and fruit quality, the following measurements were recorded:
1. Some growth characters namely length (cm), diameter of shoot (cm), leaf area (cm2) and number of leaves /shoot.
2. Yield expressed in weight (Kg) and number of fruits per tree.
3. Weight (g), length (cm), width and thickness (cm2) of fruit.
4. Fruit shape.
5. Percentages of pulp, peels and seeds.
6. Edible to non-edible portions.
7. Percentages of total soluble solids, total and reducing sugars.
8. Percentage of total acidity and vitamin C content (mg/100 ml pulp).
The nearly same obtained results could be summarized under the following main topics:
1. Some growth characters:
Growth characters namely diameter of shoot, leaf area and number of leaves /shoot were obviously varied among the two mango cvs. Taimour and Zebda. Shoot length was similar in both mango cvs. The maximum leaf area was recorded in mango cv. Taimour. Zebda mango cv had the highest shoot diameter and number of leaves/shoot.
Spraying seaweed at 0.1% and yeast at 0.3% aside from application of N via inorganic, organic and bioforms was preferable than using the three sources of N alone in improving the studied growth characters. Application of N via inorganic, at 50-75%, organic at 12.5-25% and bioform at 12.5-25% was accompanied with enhancing all growth characters compared to using N completed via inorganic source. The stimulation on growth characters was associated with decreasing percentages of inorganic source from 100 to 50% and increasing the percentages of Compost El-Neel and Biogen from 0.0 to 25%. A remarkable reduction on these growth characters was observed with reducing inorganic source percentage from 50 to 25% and increasing percentage of Compost El-Neel and Biogen from 25 to 37.5%. The maximum values were recorded when the trees received N as 50% via inorganic source, 25% Compost El-Neel and 25% via Biogen and foliar application of seaweed extract at 0.1% and yeast at 0.3%.
2. Yield per tree:
It was considerably varied among the two mango cvs. Taimour and Zebda. It was maximized in mango cv. Taimour in the first season of study and in mango cv. Zebda in the second season.
Application of N as 50-75% inorganic, 12.5-25% Compost El-Neel and 12.5-25% Biogen surpassed the application of N completely via inorganic source in improving the yield expressed in weight and number of fruits per tree. The promotion on yield was associated with decreasing percentages of inorganic from 100 to 50% and at the same time increasing the percentages of Compost El-Neel and Biogen from 0.0 to 25%. Spraying seaweed extract at 0.1% and yeast at 0.3% along with fertilization treatments was very effective in promoting the yield compared to using fertilization treatments alone.
Yield is greatly tended to decline with reducing the percentages of inorganic form of N from 50 to 25% and at the same time increasing the percentages of Compost El-Neel and Biogen from 25 to 37.5%.
Treating Taimour mango trees with N as 50% inorganic, 25% Compost El-Neel and 25% Biogen plus seaweed extract at 0.1% and yeast at 0.3% resulted in the maximum yield in the first season. In the second season, the same previous treatment gave the maximum yield of Zebda mango trees.
3. Fruit weight and dimensions:
Zebda mango cv. had the heaviest fruits and long dimensions. Fruits of zebda mango cv. characterized with oval in shape. The roundish fruits were produced from mango cv. Taimour
There was a great promotion on fruit weight and dimensions with fertilization of N as 50 to 75% inorganic source and using 12.5 to 25% Compost El-Neel and Biogen compared to using N completely via inorganic source or using inorganic source at percentages lower than 50% as well as using Compost El-Neel and Biogen each at percentages higher than 25%. The lowest values were detected when the trees were fertilized with N as 25% inorganic + 37.5% compost El-Neel and 37.5 % Biogen. Spraying seaweed extract and yeast with organic, inorganic and biofertilizer treatment had an announced effect on fruit weight and dimensions compared to N fertilization only. Fertilizing both mango cvs with N as 50% inorganic + 25% Compost El-Neel and 25% Biogen plus seaweed extract and yeast gave the best results.
4. Percentages of pulp, peels and seeds and edible to non-edible portions:
Percentage of pulp and edible to non-edible portions were maximized in fruits of mango cv. Taimour. In the same mango cv., percentages of peels and seeds were reduced.
There was a remarkable promotion on percentage of pulp as well as edible to non-edible portions of both mango cvs with fertilization of N as 50 to 75% inorganic source + 12.5 to 25% Compost El-Neel and Biogen compared to using inorganic N alone. Also, percentages of peels and seeds were tended to reduce with the previous treatment. Reducing the percentages of inorganic from 50 to 25% and increasing both Compost El-Neel and Biogen from 25 to 37.5% caused a great decline on pulp percentage and edible to non-edible portions and increased both peels and seeds percentages. The maximum pulp percentage and edible to non-edible portions and the lowest percentages of seeds and peels were recorded when N fertilization was conducted by using 50% inorganic + 25% compost El-Neel + 25% Biogen plus spraying seaweed extract and yeast.
Spraying trees of mango cv. Taimour with seaweed extract and yeast and fertilizing the trees with N as 50% inorganic + 25% compost El-Neel and 25% Biogen gave the highest pulp percentage and edible to non-edible portions and the lowest percentages of seeds and peels.
1. Chemical characters of the fruits:
Fruits of mango cv Taimour had higher percentages of total soluble solids, total and reducing sugars, as well as vitamin C content and lower percentage of total acidity compared to those in the fruits of mango cv. Zebda.
It is clear from the obtained data that application of N as 50 to 75% inorganic source, 12.5 to 25% compost El-Neel and Biogen significantly was accompanied with improving chemical fruit quality in terms of increasing total soluble solids, total and reducing sugars, and vitamin C content and reducing total acidity compared to using N as 25% inorganic source, 37.5% compost El-Neel and Biogen as well as using N completely via inorganic source. The promotion on chemical fruit quality was associated with decreasing the percentage of inorganic portion from 75 to 50% and at the same time increasing the percentage of both Compost El-Neel and Biogen from 12.5 to 25%. However, there was a great and significant reduction on total soluble solids, total and reducing sugars, and vitamin C content and an obvious increment on the total acidity with decreasing percentages of inorganic source from 50 to 25% and at the same time increasing percentages of both Compost El-Neel and Biogen from 25 to 37.5%. Application of N completed via inorganic source was favorable for enhancing chemical fruit quality than using it as 25% inorganic + 37.5% Compost El-Neel + 37.5% Biogen. Spraying seaweed extract and yeast with N fertilization was superior the application of N alone in this respect.
The studied interactions had a striking effect on chemical quality characters. The best results with regard to chemical quality characteristics were obtained when Taimour mango trees were fertilized with N as 50% inorganic + 25% compost El-Neel + 25% Biogen and sprayed with seaweed extract and yeast. The worst results were recorded on mango cv. Zebda that fertilized with N as 25% inorganic, 37.5% compost El-Neel and 37.5% Biogen.
Conclusion:
On the basis of the results obtained in this study one can confirm the following points:
1. The important of adjusting N management for improving fruiting of mango cvs Taimour and Zebda.
2. The beneficial of using the recommended rate of N for all mango cvs (i.e, 1000 g/tree in the three sources namely inorganic (ammonium nitrate), organic (F. Y. M.) and bioform (Biogen) for gaining` an economical yield.
3. It could be concluded that percentages of inorganic as well as percentages of organic and bioforms did not exceed 50, 25 and 25% out of the recommended rate of N, respectively.
4. The importance of spraying seaweed extract and yeast aside from N fertilization for enhancing fruiting of mango cvs.
5. It is suggested that fertilizing mango cv. Taimour or Zebda with N at the recommended rate (1000 g/tree) as 50% inorganic N (2.43 Kg ammonium nitrate /tree), 25% organic source (11.62 Kg Compost El-Neel /tree) and 25% bioform (250 gm Biogen /tree) and spraying seaweed extract at 0.1% and yeast at 0.3% three times for obtaining an economical yield and improving fruit quality.