Studies Regarding the Colonization Capacity of Soils with Permanent Nitrogen Fixating Bacteria, Located on Different Altitudinal Levels

The determination of the colonization capacity with permanent nitrogen fixating bacteria has been achieved indirectly through the method of using soil extracts, taken from the rhizosphere of leguminous species existing in the 4 types of permanent grasslands, located on different altitudinal levels (90m, 330m, 900m, 1800m). Treatments with soil extracts taken have been made at three species of legumes (Lotus corniculatus, Trifolium repens, Trifolium pratense), seeded on a sown perlite layer and grown in the growth chamber. Between the total amount of nodosities formed and the altitude of grasslands there is a negative correlation. At treatments with extracts taken from grasslands situated between 90-330m, there has been observed the highest number of nodosities formed on roots of tested leguminous species.