ALLELOPATHIC ACTIVITY OF RHIZOSPHERE SOIL OF ALFALFA (Medicago sativa L.)

In the laboratory condition at the Institute of Forage Crops - Pleven was studied allelopathic potential of soil from the rhizosphere of alfalfa zone on germination and initial development of the test plants - Cucumis sativus L. It was found that concentrations of the rhizosphere soil zone on alfalfa have a stimulatory or inhibitory effect on the independent seedling growth of test plants. The rate of growth and accumulation of fresh biomass (mu), as well as the dynamic development index (DDI), response index (RI) and seedling vigor index (SVI) of seedlings depend mainly on applied concentration and do not depend on the type of the growth media. The observed differences in the values of the GI regarding the growth media - "distilled water" or "agar" can be explained by their different ability to dissolved and absorbed the available allelochemicals from rhizosphere soil samples of alfalfa as the comparisons between them are made under controlled conditions.