EFFECTS OF RYEGRASS ON BIODEGRADATION OF HYDROCARBONS IN SOIL

The effects of growing ryegrass (Lolium perenne L.) on the biodegradat ion of hydrocarbons was studied in laboratory scale soil columns. Degr adation of hydrocarbons as well as bacterial numbers, soil respiration rates and soil dehydrogenase activities were determined. In the rhizo sphere soil system, aliphatic hydrocarbons disappeared faster than in unvegetated columns. Abiotic loss by evaporation was of minor signific ance. Elimination of pollutants was accompanied by an increase in micr obial numbers and activities. The microbial plate counts and soil resp iration rates were substantially higher in the rhizosphere than in the bulk soil. The results indicate that biodegradation of hydrocarbons i n the rhizosphere is stimulated by plant roots. Copyright (C) 1996 Els evier Science Ltd