ABSTRACT

This work was carried out in a field experiment at the Research and Production Station of the National Research Center (NRC) at Nubaria during two successive seasons 2006/2007 and 2007/2008. The aim was to investigate the effect of different rates of NPK fertilization on growth and the main constituents of Paulownia kawakamii T. Ito seedlings grown in sandy soil. The treatments of NPK fertilizer were: NPK at (1:1:1), (1:2:1 ), ( 1:1:2), (2:1:1) ,(2:2:1) ,(2:1:2) ,(3:1:1) , (3:2:2) as well as the control ( without fertilization).The results indicate that the application of NPK fertilizer at the different rates gave a better effect on all vegetative characteristic{plant height (cm), stem diameter (cm), fresh weight of leaves, stems and roots (gm/plant), dry weight of leaves, stems and roots (gm/plant), leaf area, number of roots and root diameter } and chemical constituents ( chlorophyll a,b and carotenoids, mineral contents of N, P and K in the leaves and total sugar contents in the leaves) compared with the control. Also, the results indicated that the application of NPK fertilizer at (3:1:1) was the most effective treatment gave significant increases in all vegetative characteristics and chemical constituents in both seasons.