Given the important role of weeds in the biodiversity and biofertilisation of agricultural soils, the main objective of our study is to estimate their impact on the availability of mineral elements in the soil and on the physiological parameters and crop yield of cereals in a semi-arid environment. Thus, two most common weeds are Galiuma parine and Fumaria officinalis in the study area with 30 and 20 plants/m 2 respectively were selected and combined with durum wheat (Triticum turgidum L. var.

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... urum), with the same densities to form three combinations on twelveplotsof 1 m 2 . These are Wheat-G. aparine (TtGa), Wheat-F. officinalis (TtFo) and Wheat-G. aparine-F. officinalis (TtGaFo) compared simultaneously with a pure durum wheat (Tt) treatment. Physical-chemical analyseswere carried out before sowing and during heading stage for the soil and after harvest for the soil and the plant (Tt). The results showed that the presence of both weeds was only beneficial effects on both physiological and wheat yield parameters and on soil fertility with a significant increase of N, P2O5, K, Na and CaCO3. Hence, we will have to think of other associations to possibly reduce the input of phytochemicals and move to develop agroecology.