Note: Fe, Festuca elata ; Ed, Elymus dahuricus ; Ms,Medicago sativa ; Fe+Ed, Festuca elata plus Elymus dahuricus ; Fe+Ms, Festuca elata plus Medicago sativa ; Ms+Ed,Medicago sativa plus Elymus dahuricus ;Fe+Ms+Ed, Festuca elata plus Medicago sativa plus Elymus dahuricus ; TN, soil total nitrogen; TP, soil total phosphorus; SOC, soil organic carbon; BD, bulk density; e , total porosity.