ROLE OF RHIZOBIA (RHIZOBIUM MELILOTI ) OF ALFALFA IN THE BIOREMEDIATION OF CONTAMINATED SOIL WITH HYDROCARBONS

Abstract

The aim of this study is to isolate the Rhizobia bacteria from the alfalfa plant and determine their efficiency in the break down and reduction of hydrocarbons from contaminated soils. The experiment was carried out in two plastic pots in order to study two factors the first factor which is the role of vaccination with the bacteria Rhizobia with alfalfa (Medicago sativa L.) in the repair of soils contaminated with the second factor fuel oil, the experiment was designed within the system (RCBD)) 5 replicates as the addition of Rhizobia vaccine (vaccine addition) marked by (R1) and another treatment (without addition) marked by (R0) and the addition of fuel oil within 3 levels (0%, 1%, 2%) marked by H0, H1 and H2 respectively. 30 plant pot were used and 3 harvesting were done for alfalfa. Rhizobia were obtained by isolating it from the root nodes of the alfalfa from one of the agricultural fields in the Al-Sophia area and studied its properties. The experimental vaccine was used on the same plant. The results showed a significant difference in the number of root nodes and total bacterial density and the number of Rhizobia and the wet and dry weight of the vegetative and root groups at the treatment of addition of bacterial vaccine and treatment of addition of fuel oil at the concentration of 1%. The increase in the amount of hydrocarbons in the vegetative part of the plant of the first, second and the third harvest and in the roots of the treatment of addition vaccine and the treatment of addition fuel oil at the concentration of 2% and achieved more overlap when the combination H2R1 (concentration of 2% with the addition vaccine) on the rest of the combinations. The amount of hydrocarbons in the soil is clearly reduced. The removal of fuel oil from the soil for the added quantity in the treatment R1 (90.33% and 80.7%) to the concentrations 1% and 2% compared to the treatment without adding R0 (89.2% and 80.0%) respectively. We conclude that the use of alfalfa and rhizobia to remove soil pollutants was very effective.