Abstract: 【Objective】To investigate the effects of the farming water returned to the corn field on the soil environment in Northern Area.【Methods】Take a large-scale dairy farm in Hohhot as an example,the effects of farming water on soil physical and chemical properties, heavy metal contents and nutrient element contents were studied by comparative analysis.【Results】After the farm water was returned to the field 6 a, soil pH value was significantly changed, and the pH value of surface, middle and deep soil were all higher than that of CK. However, soil bulk density, soil grain density and soil porosity and the content of heavy metal elements in the soil did not change significantly. The content of Cu, Zn, As, Ni, Cr, Cd, Hg, Pb and other elements did not exceed the screening value of soil pollution risk in agricultural land, and the soil environmental quality was still in a clean and safe state. Cu, Ni and Cd contents increased slightly in the topsoil. After the application of farming water, the content of nitrate, total potassium and available potassium in the soil increased to some extent, especially in the surface. The content of nitrate in the surface soil was 10 times higher than CK, but the content of ammonia nitrogen was lower.【Conclusion】After the farm water was returned to the field 6 a, nevertheless, the soil physical and chemical properties, heavy metal content and nutrient element content all changed, the soil environmental quality was still in a clean and safe state.

Key words: Northern Area, Farming water, Soil environment effects