The invention relates to a method for preventing
saline-
alkali soil salt return by utilizing a salt
isolation layer. The method includes the steps of ploughing a
saline-
alkali soil layer with the thickness of 50-70cm, and removing ploughed soil; laying an iron tailing layer with the thickness of 5-10 cm; laying a
straw layer with the thickness of 15-20 cm; laying a
charcoal layer with the thickness of 4-8 cm; and conducting
saline-
alkali soil backfill. According to the method for preventing saline-alkali soil salt return by utilizing the salt
isolation layer, the gathering speed of bottom salt on an
earth surface can be reduced, and the effect of inhibiting soil salt return is achieved; the pH and the
salt content of surface soil can be effectively reduced, the content of organic matters in the soil is increased, and a proper soil environment can be provided for
plant growth; the salt
isolation layer prepared from two
solid wastes and
biochar can achieve the effect of inhibiting soil salt return, turns waste into wealth, and improves the economic, social and environmental benefits; and the method has the characteristics of strong
operability, good effect, high benefit and capability of being popularized and used in a large scale.