We explored the inhibitory effects ofAmygdalus scoparia Spach and Atriplex canescens (Pursh.) Nutt. organs on the soil seed bank dynamics in semi-arid areas. Ex-situ experiments were done using aqueous extracts [0 (control), 25, 50, 75 and 100 g.L-1] of shoot, leaf and seed coat on germination indices of test grasses (Stipa barbata, Bromus tectrrom, Hordeum leporinum) and forbs (Stachys inflata and Alyssum desertorum). In-situ experiment was also done based on soil seed bank germination indices at different distances from the plant stands. Both species extracts significantly influenced the seed germination, speed of germination and vigour index. The seed coat aqueous extracts at 100 g.L-1 concentration was most inhibitory. Also, auto-inhibitory effects were lower than their inhibitory effects on neighboring plants species. In aqueous extracts of A. canescens, 4- allelochemicals identified were: Benzenecarbothioic acid, benzene, azidomethyl and 1-Hexanol, while, extracts of A. scoparia contained only two allelochemicals: Heptane and coumarin. The field survey showed that seeds in plants rhizosphere had the lowest seed germination and vigour and these increased significantly with increasing distance from plants stand (R-2 =0.99). The seed coat aqueous extracts of both donor species decreased the germination indices of forbs.