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To combat desertification and lessen its effects on the impacted population, the Algerian government chose fodder plantation strategy by introducing Atriplex canescens, an invasive plant with high fodder value brought from the USA. A. canescens into Algerian pastures can potentially alter the floristic procession of the areas into which it is introduced. The objective of this work is to analyze the effect of planting A. canescens on the biodiversity and soil properties of a steppe pasture. In a planted rangeland, a floristic study is carried out using the linear method. Physico-chemical analyzes of the soil of this rangeland are carried out on a thickness of 0-40 cm. The results showed presence of 58 species, 46 genera and 22 families, with the predominance of Aster-aceae and Poaceae. The specific contribution of the two locale species Macrochloa tenacissima and Artemisia campestris decreases as soon as A. canescens is present in the rangeland. The soils water content is ranged from 0.356 to 1.291. Total nitrogen content in the planted rangeland, was within the normative range of 0.021 to 0.02 g/kg. A lowest value of pH 7.38 is observed in the plantation and the highest value 8.26 is measured in the non-planted rangeland. Electrical conductivity ranged from 0.155 mmhos/cm to 0.428 mmhos/cm. Sodium content varies from a minimum of 1.407g/kg to a maximum of 3.423 g/kg observed in the planted rangeland. Assimilable phosphorus levels are very low, almost traces. The observed potassium values are between 0.465 g/kg and 1.207 g/kg. Overall, A. canescens contributes to soil fertility but in the long term, it can compete with the presence of local plant species, particularly perennial ones. [ABSTRACT FROM AUTHOR]

The Algerian steppes face ecological imbalances due to overgrazing, cereal cultivation, and resource pressure. In response, the government implemented the "Great Works for the Development of Steppe Pastures" program in 1994, planting the nonnative Atriplex canescens, a shrub resistant to cold, drought, and salinity. However, introducing exotic plants can harm native biodiversity through allelopathy interaction. This work aims to test the allelopathic potentiel of A. canescens on the most representative North African steppe plant Macrochloa Tenacissima. Phytochemical tests are performed on the aerial parts of these two plants. Aqueous extracts are prepared from the aerial parts of A. canescens with three concentrations respectively T0 (0%), T1 (2.5%) and T2 (5%), and are applied in situ for 45 days on M. tenacissima plants. The response of M. tenacissima to the extract of A. canescens is monitored by measuring chlorophyll and proline in the fresh leaves of the target plant M. tenacissima. The results showed the presence of allopathic molecules in the aerial parts of both plants, notably Alkaloide, flavoniode, tannins, triterpnoide, Quinon and phenolic acid. The response of M. tenacissima to the application of A. canescens extract caused during the trial remarkable change in the total chlorophyll content of M. tenacissima, with reductions of 1 to 4 (mg/g FM) observed at the end of 45 days of application. The highest decrease is observed for treatment T3. After 45 days of treatment with A. canescens extract aqueous, M. tenacissima showed the highest proline accumulation 2.6 (mmol/g MF) for the treatment T3. Our findings show that A. canescens can induce physiological disruptions in M. tenacissima. [ABSTRACT FROM AUTHOR]