الفهرس 
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Abstract
This investigation was carried out during two successive seasons of 2004 and 2005 in the Nursery and Laboratory of Faculty of Agriculture, Minia University, to improve the growth and development of Khaya senegalensis (Desr) A. Juss seedlings by application of mineral NPK at N0P0K0 , N1P1K1, N2P2K2, N3P3K3 and N4P4K4 and ten biofertilization treatments, phosphorein (6, 12 and 18 g/ seedling), Nitrobein (6, 12 and 18 g/ seedling) and phosphorein + Nitrobein (6, 12 and 18 g/ seedling), as well as, control without biofertilizer. The amounts of N0, N1, N2, N3 and N4 were 0.0, 1.5, 3, 4.5, 6 g/ seedling of ammonium sulphate (20.6% N), while P0, P1, P2, P3 and P4 were 0.0, 0.75, 1.5, 2.25, 3 g/ seedling of Calcium superphosphate (15.5 % P2 O5) and those of K0, K1, K2, K3 and K4 were 0.0, 0.375, 0.75, 1.125 and 1.5 g/ seedling of potassium sulphate (48 % K2O), respectively.
Different vegetative growth traits were recorded and three photosynthetic pigments contents and N, P and K percentages were determined.
The obtained results could be summarized as follows:
1- Effect of NPK fertilization treatments:
1-1 Vegetative growth aspects:
• In most cases, mineral NPK fertilization treatments had significantly improved all vegetative growth characters of Khaya senegalensis (Desr) A. Juss seedlings compared with N0P0K0 treatments.
• Mineral NPK fertilization significantly augmented seedling height, stem diameter, number of leaves/ seedling, as well as, fresh and dry weight of leaves, seedling without leaves and roots/ seedling.
• Increasing the level of NPK fertilization resulted in a gradual increment of all above mentioned parameters.
• The most effective NPK fertilization treatment which gave the highest values regarding all vegetative growth traits was N4P4K4.
1-2- Chemical composition:
The examined NPK fertilization treatments led to a significant stimulation of the three photosynthetic pigments (chlorophyll a, b and carotenoids) contents in the fresh leaves of Khaya senegalensis (Desr) seedlings in comparison with untreated seedling (N0P0K0). The highest contents of the three pigments were obtained due to the following treatments in descending order: N4P4K4, N3P3K3, N2P2K2 and N1P1K1. A gradual increases of N, P and K % were obtained by a gradual increase in the NPK fertilization rate from N1P1K1 to N4P4K4.
2- Effect of biofertilization treatments:
2-1- Vegetative growth characters:
• In most cases, inoculating the seedlings of Khaya senegalensis (Desr) with phosphorein and/or Nitrobein significantly increased vegetative growth parameters including seedling height, stem diameter, number of leaves/ seedling, as well as, fresh and dry weight of leaves/ seedling and seedling without leaves and roots / seedling compared with the control treatments (untreated seedlings).
• The increments of all aforementioned vegetative growth parameters were gradual and parallel to the increase in phosphorein and / or nitrobein levels.
• Nitrobein was superior the application of phosphorein, while phosphorein was favorite in improving roots fresh and dry weights than using nitrobein. In this respect combined application of both Nitrobein and phosphorein was much more effective than application of either one alone. Therefore, the mixed biofertilizer applied at high level exceeded all other biofertilizer treatments.
2-2- Chemical composition
The contents of the three photosynthetic pigments namely, chlorophyll a, b and carotenoids in the fresh leaves of Khaya senegalensis (Desr) A. Juss seedlings were gradually and significantly increased due to the gradual increase of phosphorein and Nitrobein rate from 6 to 18 g/ seedling compared with untreated control treatment. All biofertilizer treatments significantly increased N, P and K in the leaves, over those of untreated seedlings.
3- Effect the interaction between mineral NPK and biofertilization treatments:
3-1- Vegetative growth parameters:
In most cases, inoculating the seedlings of Khaya senegalensis (Desr) A. Juss grown in sandy soil with a mixed of phosphorein plus nitrobein combined with N4P4K4 treatment significantly augmented all studied vegetative growth characters.
3-2- Chemical composition:
Inoculation the seedlings grown in sandy soil with a mixture of phosphorein + nitrobein combined with high level of NPK treatment increased chlorophyll a, b and carotenoids and leaf percent of N, P and K.