Influence of Rhizobia Inoculation and Rock-Phosphate on Biomass and Nitrogen Content of Leucaena leucocephala (Lam.) De Wit Seedlings

The study was carried out in the nursery of the Experimental Station of Forestry and Wood Technology Department, Faculty of Agriculture, Alexandria University during the period from 1st May, 2017 to 31st March, 2018. It aimed at evaluating the influence of two races of Rhizobium (TAL82 and TAL582) on the overall biomass and the total N content in the leaves of Leucaena leucocephala seedlings. In addition, the study aimed at finding out, if any, the impact of rock- phosphate )RF) amendment on the nodulation and growth efficiency of L. leucocephala seedlings. Seedlings were inoculated with pure cultures of both strains, then fertilized with rock-phosphate on 7th October, 2017 using 4 levels; 0.0, 0.5, 1.0 and 2.0g / kg soil. Both strains (TAL82 and TAL582) developed typical nodules. However, solubility of RF potential was affected by the strain tested as expressed in terms of growth parameters. The strain TAL582 showed, better and faster growth promoting effect than TAL82 in L. Leucocephala seedlings. The fertilization with P induced promoting nodule formation earlier than unamended control. Results showed that fertilization with 1g RF/ kg soil is more effective than the higher tested level (2g RF/ Kg soil). Therefore, it is recommended to inoculate seedlings of L. Leucocephala with Rhizobium particularly TAL582 strain and to add P as a fertilizer at the rate of 1gRF/Kg soil to achieve the best plant growth in significant short time.