Abstract: The effect of alfalfa introduced in farmland ecosystem on soil eco-environment is studied in this paper. Experimental results show that after three years planting of alfalfa, soil aeration increases by 2.37—5.34%, soil organic Ccontent by 0.349—0.600%, average crop yield by 25%, and filtration coefficient by a factor of 1.7—6.5. The ratio output and input of planting alfalfa is 0.36—0.39times higher than planting crop alone.

Key words: Alfalfa, Soil eco-environment, Ecological benefit, Economic benefit, potential geographical distribution., foxtail millet, ArcGIS, species distribution model