SYMBIONT EFFECT OF RHIZOBIUM-BACTERIA AND VESICULAR-ARBUSCULAR MYCORRHIZAL FUNGI ON PISUM-SATIVUM IN RECULTIVATED MINE SPOILS

The frequency (F%) of spontaneous endomycorrhizal fungal infection (AM F) and the root nodulation of Pisum sativum L, was studied after 8 and 15 years of recultivation in 4 soils (andesitic tuff yellow sand, yel low clay, and grey clay) disturbed by mining activities. The effects o f Rhizobium inoculation and the interaction of both microsymbionts wit h plant production were also examined along with humus content and the humus stability coefficient, in the following variations: control, NP K fertilizer, NPK + lignite, NPK + straw and sewage sludge. Dump spoil s originating from deep geological layers were poor in organic materia ls. After 12 years of recultivation, the humus content increased signi ficantly. No such increase was noted in grey clay and the natural, bro wn forest soil used as an undisturbed (control) sample. The degradatio n of soils by mining brings about a decrease in the rhizobial and myco rrhizal population, so the number of spontaneous Rhizobium nodules is relatively low and does not influence the yield of peas. Inoculation w ith a selected, effective strain of Rhizobium leguminosarum bv. viceae , however, enhanced dry matter production in these microbiologically d egraded soils. Although the frequency of AMF infection was also higher after rhizobial inoculation, no positive correlation was found betwee n dry matter production of pens and the F% of AMF. Spoils treated with lignite, straw, and sewage sludge had an especially high level of spo ntaneous mycorrhizal populations, indicating that organic materials ha d a favorable effect on the recultivation processes and fertility of m ine spoils.